Attic – CheckThisHouse Home maintenance, remodeling, repair, and improvement tips for your property Tue, 13 Apr 2021 22:28:34 +0000 en-US hourly 1 5 Reasons to Properly Insulate Your Attic Mon, 26 Oct 2020 11:13:46 +0000 If it’s your first time to insulate your own home, or if you’re refurbishing the insulation on a newly purchased property, where should you start? The US Department of Energy, as well as most seasoned building contractors, will recommend that you start with the attic area. The rationale is that heat naturally rises, and the ... Read more]]>

If it’s your first time to insulate your own home, or if you’re refurbishing the insulation on a newly purchased property, where should you start?

The US Department of Energy, as well as most seasoned building contractors, will recommend that you start with the attic area.

The rationale is that heat naturally rises, and the attic or the uppermost layer will retain much of the heat generated in the house.

Insulating an attic can be a tedious job, and it’s one that many homeowners like to put off for as long as they can. But if the improvements are done well, and if you choose the right insulation solutions, the hard work will go a long way.

You’ll be thankful you paid extra attention to your attic space when weather extremes hit and when you start noticing the difference in your energy bill. 

Here are five reasons to set aside time, money, and effort into properly insulating your attic. Don’t wait until before an extremely hot summer or a bitterly cold winter to start this home improvement project!

1. There’s a Variety of Insulation Solutions Out There

No home attic is exactly the same as another’s. If you find out about a neighbor spending a lot on their attic insulation project, don’t assume that the same will apply for you.

You can shop at a local construction supply store to find effective but affordably priced insulation materials for your attic. Some available varieties are fiberglass batt insulation, spray foam insulation, or blown-in cellulose insulation. 

Just remember: if you live within the US Department of Energy’s Climate Zones 6 or 7, you will need R49 insulation. That material’s R-value, or resistance to heat transfer, is high enough to insulate your attic area properly.  

2. It Will Make Your Home More Comfortable During Weather Extremes

Poor insulation in the attic can result in two unpleasant extremes for your home.

In the summer, the heat can stay trapped in your attic and make your indoor temperature warmer than it should be.

Conversely, in the winter, the heat may migrate too quickly up to your attic. Without a permeable lid to trap that heat, the temperature inside your home will be too chilly. 

In either extreme, your indoor temperature will not be very stable. You’ll resort to overworking your heating or cooling appliances, or you and your family members will put up with the discomfort.

You don’t need to, however, if you decide to put the extra care into insulating your attic. It’s an investment that will keep you both warm enough and cool enough all year round. 

3. It Will Save You a Lot in Terms of Energy Costs

If your home is under-insulated, you’ll be consuming more energy to achieve your ideal temperature.

Again, because of that, you may be exhausting your indoor heater or your air conditioner just to maintain that balance. And at the end of the month, it will reflect heavily on your utility bill. 

On the flipside, insulating your attic can save you a great deal of money on energy costs. As per the Department of Energy, you can shear off between 10% and 50% of your heating bill if your attic is properly insulated.

A well-insulated attic will keep your energy costs more manageable for several years. 

4. It Can Protect the Upper Part of Your Home from Damage

Insulating your attic can also improve the structural integrity of your home. In an under-insulated attic, excess heat can sometimes accumulate right under the roof.

That can result in various forms of damage, like softened plywood or cracked shingles.

An attic that’s not properly insulated may also allow water vapor to seep in. This can slowly destroy the ceiling and walls of your home, as well as make your indoor environment feel unpleasantly clammy. 

Thus, reinforcing your attic with insulation can also safeguard the upper parts of your home against further damage. You’ll have a few less attic and roof repair jobs to worry about.  

5. It Results in a Cleaner and Healthier Indoor Environment for Your Family

Lastly, a well-insulated attic may make a big difference in terms of how healthy it will keep your indoor environment.

The insulation will be good at keeping mold, mildew, dust, and other threats to your health at bay. You and your loved ones will be less at risk of getting asthma attacks, allergy attacks, or other bouts of sickness caused by poor indoor air quality. 

You can rest easy about your family’s general health when you have proper insulation in your home. Your attic should be the priority, especially if your home’s most important living spaces—like the bedrooms—are upstairs. 

Conclusion: Insulate Your Attic for a More Livable Home

Suffice to say, refurbishing your attic insulation system will have a noticeable effect on your indoor temperature, your energy consumption, and your family’s overall health.

If you’re having a difficult time with the particulars, like choosing which insulation material is best for your home, don’t hesitate to ask a professional!  


How to Inspect Your Home to Avoid Wildlife Pest Infestations Mon, 19 Oct 2020 11:53:05 +0000 If you are a homeowner, chances are you have thought about or had experiences with pest problems. If you are lucky, you have never had a pest infestation. Pest infestations, especially mice and other rodents, are terrible because it seems like they will never all be taken care of. Luckily, there is no need to ... Read more]]>

If you are a homeowner, chances are you have thought about or had experiences with pest problems. If you are lucky, you have never had a pest infestation.

Pest infestations, especially mice and other rodents, are terrible because it seems like they will never all be taken care of.

Luckily, there is no need to go through this situation if you spend time and take precautions against it.

All you need to do is inspect your home so that you can take precautions to avoid wildlife pest infestations.

The Foundation

If you are really worried about a mouse infestation, in addition to other rodents, checking your foundation will be your biggest concern.

If you find any gap or hole that is bigger than a quarter of an inch, you need to fix it. The easiest way to fix small gaps or holes is to use a sealant or steel wool.

If it is a larger hole, consider using a small piece of sheet metal.

Always check where your furnace and other appliances go outside, as there are often holes around these.

A sealed foundation is highly important to keep rodents out, so be sure to spend time inspecting it.

The Roof

Another big concern with most homes is the roof. You should regularly inspect your roof and gutters because many roofs have holes and gaps along the shingles, the soffits, and vent screens.

These can usually be fixed with sealant or sheet metal, however it is important to nail down shingles and possibly replace them if you have to.

Also be sure to check your chimney to make sure no animals can get into it, as mice, squirrels, and birds often find their way in through chimneys.

Doors and Windows

Many wildlife pests can easily find entry into a home if the door and window frames are loose or cracking. Be sure to fix or replace broken window panes, door screens, and window screens.

Also be sure to inspect weather stripping and make sure it is tightly sealed to the door or window so that there is no room for anything to squeeze through. If you see any damage due to gnawing, be sure to apply a metal kick plate or some other metal solution

Look over every part of the door frames and window frames for any small holes or gaps and seal them if you find any. 

Walls and Attic

While it may seem like a no-brainer, many people forget to even just examine the exterior walls of their home.

If you see any holes or gaps in the siding or the actual wall, it is important to get them sealed with sheet metal or sealant, as these are direct routes for mice, rats, birds and other pests to get into your home with minimal effort.

In a related sense, attics often feature holes and gaps along their external walls. Mice, rats, raccoons, and other critters especially love attics because they provide excellent warmth and nesting areas.

This can cause big problems, so it is important to keep them out. Seal any gaps and holes with sheet metal or sealant.

There’s always the option of finding a professional for help for the most effective inspection and repairs. 


If you happen to have a garage that is connected to your house, you will need to check your garage for gaps and holes very well.

Especially pay attention to where your garage connects to your house. Even small holes and gaps need to be filled, as mice can squeeze through the smallest of holes.

If you have attic access out in your garage it is important to check the ceiling of your garage as well, as it can be an often overlooked entry point for rodents.

Yard and Property

Once you have inspected your home, it is time to expand your inspection outwards.

Many homeowners often overlook the importance of keeping their yard well-kept, as it helps prevent critters from being attracted to your property in the first place.

Look for any woodpiles, debris piles, tall weeds and grass, short shrubs, and any fruit that has fallen from trees.

Clean up any and all of these things you find, as it dramatically reduces the appeal of your yard.

Also be sure to trim back any tree branches that come close to your roof, as this provides a way for raccoons, squirrels, mice, and rats to find their way onto your roof and eventually into your attic. 

5 Things Every Home Owner Should Know About Their Attic Mon, 08 Oct 2018 18:38:08 +0000 Every homeowner knows all too well the stages of wondering what to do with their attic: cautiously exploring, ambitiously attempting to make use of it, and ultimately giving up and deciding to pretend that it isn’t even there. Maybe it’s spooky, maybe it’s a mess, or maybe it’s just a massive pain in the butt ... Read more]]>

Every homeowner knows all too well the stages of wondering what to do with their attic: cautiously exploring, ambitiously attempting to make use of it, and ultimately giving up and deciding to pretend that it isn’t even there. Maybe it’s spooky, maybe it’s a mess, or maybe it’s just a massive pain in the butt to get up into.

Whichever excuse your using, it’s time to face the facts – we can’t ignore our attics forever.

To prove why, we’ve put together a list of the top 5 things every homeowner should know about their attic – you’ll thank us later.

  1. Attics Are A Great Place For Your Furnace

Most houses have their furnaces in the basement or in a designated “utility closet” on the main floor, but most homeowner’s don’t realize that there is another space in their house that can be a great option – the attic.

Of course the attic can be a hassle to get in and out of the one or two time’s a year you actually need to service the furnace, but there are many advantages to combat this slight inconvenience.

  • Having the furnace in the attic affords you additional usable space in your basement or on your main floor – space you can utilize for more living space, more storage space, etc.
  • Having your furnace in the attic means the ducts running from the attic to the upper and main levels of the house will be shorter – shorter distances for the heat to travel equates to less heat loss, meaning an attic furnace is actually more efficient.
  • An attic is a great option if you are expanding the size of your home and require a second furnace – rather than having to rearrange your current utility space to accommodate room for a new furnace you can simply place the new one in the attic.

Just note, there are a number of regulations that must be met when placing your furnace in the attic – safety first!

  1. Attics Are Also A Great Place For Mould and Pests

Mould and pests are two things you don’t want to find in your attic, but that can be quite common.

Even the smallest of leaks in your roof after a heavy rain or long, snowy, winter can result in trapped moisture in your attic. This moisture causes mould, which can damage the structure of your roof and attic as well as causing allergens that can be hazardous to your health. The best way to combat this is to keep your roof, especially the shingles, in good condition.

In addition to mould, you can also often find rats, bats, raccoons, and a variety of other little critters making themselves at home in your attic. For small critters, you can usually trap and release them yourselves, for the bigger one’s you may want to enlist the help of a professional. But remember – use humane methods of removal only!

  1. Attic Insulation Is Crucial For Keeping Your Home Comfortable and Healthy

And it ensures your attic is performing as efficiently as possible – which also saves you money!

It’s easy to check if your attic is properly insulated – if you see bare spots along the walls or ceiling, or the insulation that is there looks thin, worn out, or damaged (especially water damage), you may want to have a professional come in and touch the insulation up.

There are a few options for insulation, such as loose fill insulation or blanket insulation, and the newer option, spray foam polyurethane. Of course, each option has their pros and cons, which will depend on factors such as your budget and what you intend to use the attic for.

  1. Your Attic Is Incredibly Important To The Structure Of Your Home

Things that may appear to be small issues can easily be due to larger problems that are out of sight. If you notice any leaks or cracks, it is best to have them checked out as soon as possible.

While these may be isolated to the attic and be easily repaired, they may also indicate more substantial problems such as cracks in the foundation of your home or even a variety of other structural issues.

The longer issues like these go unnoticed, the more expensive they will be to repair and the more hazardous they become to the integrity of your home – don’t hesitate to call a professional, even if the problem you have found seems minor, because it may not be.

  1. You Should Check Your Attic Every 3-6 Months

As you can see, there are many different problems that can arise within your attic. In order to catch these problems before they grow out of hand, professionals recommend you inspect your attic every 3 to 6 months.

By inspecting your attic regularly, you should be able to keep your problems to a minimum and only have to worry about regular maintenance. This will save you time and money, keep you safe, and keep you sane – a few minutes of your time every few months seem worth that!

Is there anything else you think homeowners should know about their attics? Share below!




Extreme Amount of Moisture in my Attic | Attic Ventilation Sun, 21 Feb 2010 23:04:46 +0000 Condensation dripping from an H clip in poorly ventilated atticI have an extreme amount of moisture in my attic, I recently had my roof re-shingled and had the roofer add 2 more vents for better ventilation. There is a build up of frost in certain areas of my roof, it has been an extremely cold winter, would lack of insulation cause this and how deep should the insulation be?]]> Condensation dripping from an H clip in poorly ventilated attic

Attic moisture is a very common problem in cold climates.

Attic moisture - Condensation dripping from an H clip in poorly ventilated atticAttic moisture - Frost developing on roofing nails and decking in poorly ventilated attic - black mold will follow shortlyLet’s answer the attic moisture question below (from one of the website visitors): I have an extreme amount of attic moisture, I recently had my roof re-shingled and had the roofer add 2 more vents for better ventilation.

There is a build up of frost in certain areas of my roof, it has been an extremely cold winter, would lack of insulation cause this and how deep should the insulation be?

Attic moisture - Missing attic floor insulation allows heat transfer between the conditioned space of your home and the atticLack of insulation on the attic floor (house ceiling) is definitely one of the most important reasons for attic moisture resulting from migration of warm air into the attic, and moisture condensation on the roof framing / decking.

Although, properly designed attic ventilation would most likely remove this warm air before it starts elevating attic moisture levels and condensing. However, we’re still loosing expensive energy.

Attic moisture - Vents along the lower portion of the roof, one of the solutions if there is no soffit - help to maintain air circulation and remove attic moistureInstallation of additional roof vents helps to control attic moisture under one condition – they have to be distributed properly in order to maintain air circulation between the lower and upper section of the attic, or sideways (between gables). Those two additional roof vents (I’m assuming on top of the roof) won’t help much if there’s nothing or not enough vents (air intakes) along the bottom edges of your roof.

Depending on the roof design, installation of  “lower” vents could become a challenge – the best example would be a roof with no overhang /soffits to accommodate vents. In such case, attic moisture control can be performed utilizing the following 3 passive vent options:

  1. Drip edge vents installed along the bottom edge of the roof / right above the gutter
  2. A few regular vents on the roof surface, within 1/3 of the distance between the bottom and top section of the roof plane (not an ideal situation but sometimes the only one)
  3. Hip vents – the same as a ridge vent (almost)

Attic moisture - Humidistat and temperature sensor equipped attic power vent helps to remove attic moisture - condensationUnfortunately, any significant amount of snow and / or ice accumulating at the lower portion of the roof, inside the gutter (for a drip edge vent) will most likely compromise the air flow and prevent attic moisture removal. It sounds like there’s no solution… well, if you combine a humidistat controlled attic power vent, with any of the above described passive vents, you’ll have much better chance of removing attic moisture and preventing frost and condensation from building up in your attic.

The insulation issue / how deep the attic insulation should be to minimize attic moisture problem?

It all depends on your geographical location and type of the insulation installed. The most commonly used for the attic floor are blown-in types of insulation: cellulose and fiberglass.

Attic moisture - Frost and black mold covered roof decking surface, heavy condensation stains on roof framing - caused by too much insulation stuffed into the soffit and blocking soffit ventsFor attic insulation amounts and sample calculations please visit – attic ceiling insulation

You can also find more information about your attic issues (including more about attic moisture) on my website under “Attic

Please, let me know if you have any other questions, and please – take care of attic moisture and condensation issues before it gets moldy.

How Much Attic Insulation You Need: Insulation Zone Map Thu, 14 Jan 2010 23:04:40 +0000 Lack of the floor attic insulation (house top floor ceiling), or inadequate amount of the insulation are definitely some of the most important reasons responsible for migration of conditioned (hot or warm) air into the attic. During the cold season, missing attic floor insulation or low levels of attic insulation might be devastating, result in ... Read more]]>

Lack of the floor attic insulation (house top floor ceiling), or inadequate amount of the insulation are definitely some of the most important reasons responsible for migration of conditioned (hot or warm) air into the attic.

During the cold season, missing attic floor insulation or low levels of attic insulation might be devastating, result in excessive condensation, attic mold growth, ice dams, and deterioration of the roof decking surface.

With sufficient attic ventilation, conditioned air that has penetrated ceiling surface into the attic would be discharged from the attic into the house exterior, sometimes without even causing any problems.
However, your heating and / or air conditioning system will operate much longer and more often in order to keep up with the thermostat settings – that’s more cost to you.

How much attic insulation do you need in your area?

The amount and R-value of your attic floor insulation depends on your geographical location / zone.

The R value or R-value is a measure of thermal resistance (ability to resit heat traveling through it) used in the building and construction industry. The higher R-value – the better insulation performance. (Full Wikipedia definition).

Some states, do not have building codes regulating energy efficiency at all, and each existing municipal code might be different. Therefore, you may want to check with your local building department how much attic insulation is required in your particular area before you start a project.

Use the US map and the chart below to determine recommended attic insulation R-values in your area and how much attic insulation you need (source – Energy Star website ).

How much attic insulation you need - United States insulation amounts map

Zone Recommended insulation values based on your current attic condition
There’s no attic floor insulation – install following: If you have 3″ – 4″ of  the attic floor insulation, install additional:
1 R30 to R49 R25 to R30
2 R30 to R60 R25 to R38
3 R30 to R60 R25 to R38
4 R38 to R60 R38
5-8 R49 to R60 R38 to R49

How much attic insulation on the floor you need (its thickness) will depend on the insulation type / each one has a different R-value, so you’ll need more or less of the particular insulation type to achieve the same thermal protection.

How much attic insulation you need – thickness calculation example:

The average R-values of two most popular attic floor insulation types are (you’ll find the exact R-values on the insulation packaging material):

  • Loose fill cellulose  3.2 to 3.8 per inch
  • Loose fill fiberglass  2.2 to 2.7 per inch

To find out how much attic insulation you need for a home located in #4 zone, without any existing attic floor insulation (according to the table recommended minimum R-value is R38), wee need to perform this simple calculation:

R38 divided by R3.2 (cellulose) = 11.875″  loose fill  insulation thickness
R38 divided by R2.2 (fiberglass) = 17.27″  loose fill  insulation thickness

I hope that the above map and tables will help you determine how much attic insulation you should have to prevent many serious problems from happening, and to keep your monthly energy bills as low as possible.

How to Get Rid of Mold in Your Attic – Kill Stubborn Mold! Tue, 04 Aug 2009 21:00:54 +0000 How To Remove MoldLet me give you an advice on how to get rid of attic mold, something to consider before signing a contract with a mold remediation company.]]> How To Remove Mold

Getting rid of mold in the attic used to be one of the most “popular” concerns addressed by my clients after the home inspection. I’ve already covered why is black mold growing under the roof, and how to prevent or stop attic black mold from growing in my previous posts.

Now is time for getting rid of mold in your attic

Getting rid of mold in the attic - roof framing not contaminated, roof and decking replacement might be less expensive than mold remediationBut before I explain the “typical” way of getting rid of mold, let me give you a little advice, something to consider before you sign a few (if you lucky) thousand dollars contract agreement with a mold remediation company.

Getting rid of mold in the attic TIP (to consider):

  • Let’s assume that you are in the middle of a real-estate transaction, and the home inspector just revealed to you, that your entire house attic is contaminated with black mold. If you have a brand new roof, you can only blame yourself or try to blame the roofing contractor for not checking the attic before replacing the roof (he’ll laugh at you unless you’ve actually asked the guy to check the attic before the roof replacement). If you have an older roof, the importance of this getting rid of mold advice is even greater.
  • Call at least 2-3 mold remediation companies for an estimate – specify to the representatives, that you not only want to have the mold removed, but also attic ventilation system corrected / installed if necessary / ask if the attic insulation requires replacement. With the numbers from the mold remediation contractors, call 2-3 roofing contractors and ask them for a quote on the roof replacement cost including decking boards / plywood (ask the roofer to check the attic area), and your attic ventilation improvement.

Be cautious if they only suggest humidistat controlled power vent installation – without properly functioning soffit vents, any type of vents along the lower portion of the roof, or gable vents, this might not be an adequate solution.

  • If the attic insulation replacement is not required (it most cases it will not be possible to tell without laboratory testing), make sure it’s sealed with plastic foil before the roof and its decking replacement. Fold the foil sealing its contents after the contaminated decking has been removed, and dispose of as a regular waste (EPA recommendation)
  • If you only have a small area of attic contaminated with black mold, the roof replacement option would be more expensive. But instead of getting rid of mold from an entire attic by performing black mold remediation procedures, it might be cheaper (or even much cheaper) to remove all contaminated decking, install completely new roof and correct ventilation issues. I’ve seen $3,000.00 – $10,000.00 invoices for the attic black mold remediation process in approximately 1000 – 1200 square feet of attic area.

Benefits of getting rid of mold in your attic by replacing the roof

  • A few befits of the roof / decking replacement over the other types of getting rid of mold procedures:
  1. Roof and decking replacement might be cheaper than getting rid of mold be cleaning an entire black mold contaminated attic
  2. The house attic black mold that was killing your real-estate transaction is gone
  3. Attic ventilation improvement is much easier during the roof replacement and often handled with no additional or insignificant cost
  4. After getting rid of mold using this method the buyer gets a brand new roof

Even if the roof replacement price is slightly higher than getting rid of mold with a traditional mold remediation process, it is still worth to take it under the consideration because you’re gaining a valuable house update (new roof), that will be disclosed on a real-estate listing.

In some cases, the roof decking and framing are contaminated, and decking replacement only would not entirely solve the problem. In such case, you’d have to clean mold contaminated joists and / or trusses.

Killing attic black mold and getting rid of mold the typical way

This isn’t a black mold killing or mold cleaning case study, it is just an explanation based on my observations and EPA (Environmental Protection Agency) recommendations.

Even if you’re dealing with a small mold contaminated attic area – 10′ x 10′ is the maximum area recommended by the  EPA to be treated by non-professionals, forget about getting rid of mold / killing mold by spraying it with bleach or other disinfectants. It ‘s been confirmed by laboratory testing that they don’t kill all of the spores and in most cases, you’ll be just making a mess.

The best way for getting rid of mold in the attic (black mold and any other mold) is to remove it from the surface it’s growing on, or remove the contaminated surface!

The following “getting rid of mold” / cleanup methods are recommended by EPA and all of them can be applied in the attic, assuming that it is a small area (up to 10 sq. feet).

  1. Get rid of mold-contaminated surfaces by using a wet vacuum – the type you can fill its tank partially with water to contain mold residue from the contaminated surface
  2. Wipe the surface with a damp sponge or rag – use clean water or wood cleaner
  3. Use a high-efficiency HEPA vacuum cleaner on thoroughly dried surfaces, and dispose of the picked-up contents in well-sealed plastic bags
  4. Remove all contaminated material, seal it in plastic and dispose of as regular waste. They recommend using HEPA vacuum after this, but in the attic you’d most likely have to remove the floor insulation (if contaminated). You can also cover the insulation with plastic foil, and fold the foil sealing its contents after the cleaning process.

You may or may not have any allergic reactions to the attic black mold. However, while getting rid of mold always use protective equipment, especially while working in the attic area where you are exposed to the insulation fibers and dust.

Also, as minimum protection, while getting rid of mold EPA recommends Gloves, N-95 respirator and eye protection (preferably fully enclosed goggles). As additional protection you can add a half-face respirator or full-face respirator with HEPA filter, disposable full-body clothing, headgear, and foot coverings.

Getting rid of mold in the attic if large section or an entire attic is contaminated

I personally wouldn’t even attempt to do it myself, so my suggestion is:

  • For getting rid of mold in a heavily contaminated attic use a professional mold remediation company – check their background and check it “manually” by calling their clients! Ask for clients who had their attic mold remediated approximately 1-2 years ago – it usually takes a winter for the mold to start growing again if the job wasn’t fully completed.

Getting rid of mold in the attic - remove it, do not encapsulate!Insist on removing the attic black mold completely instead of encapsulating it (Media Blasting methods give the best results). Encapsulation is simply a process of covering the mold-contaminated surface with paint (paint-like product) that contains (or at least some of them do) mold killing chemicals.

The video below explains getting rid of mold in the attic with the soda blast mold remediation process, and you can immediately see the results of this procedure.

After properly getting rid of mold in your attic and having all of the issues responsible for black mold growth corrected, which is even more important than mold removing, it will not re-grow / no need for encapsulating.

  • Hire a different contractor for mold testing and mold remediation to eliminate conflict of interest
  • Make sure that you perform an independent clearance test after the mold remediation process completion. The clearance test is to determine if there are any mold spores remaining in the previously contaminated area.

Getting rid of mold in the attic - partially encapsulated attic mold - your money wasted on poorly performed work. Always remove mold and correct moisture problem.Getting rid of mold in the attic - rotten section of mold contaminated roof deckingExtremely important! – personally examine the attic (or have somebody you can trust do it for you) after getting rid of mold / performing mold cleaning procedures. I’m not exaggerating – I’ve seen several attics after “professionally performed remediation”, they either didn’t know the correct way of getting rid of mold in the attic or they didn’t care (close to $10000 price tag!).

After getting rid of mold the wood surfaces should be perfectly clean (like brand new), unless there was some rotting that resulted from leaking roof or extremely humid conditions in the attic – those sections of wood should be either replaced or reinforced from underneath. You don’t want anyone to fall through the roof while servicing it or just inspecting.

This concludes getting rid of mold in the attic & killing mold in the contaminated attic but I highly recommend going a little deeper into the “attic” subject by reading my other posts in the “attic” category.

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Proper Attic Ventilation With Vent Chutes & Roof Soffit Vents Mon, 27 Jul 2009 02:24:50 +0000 Attic VentilationHouse attic ventilation & vent chutes Vent chutes that are also called baffles or rafter vents play an important role in your attic ventilation system. House attic vent chutes and their three important roles in attic ventilation: vent chutes provide unobstructed air passage between the soffit vents and the attic vent chutes allow installation of attic floor insulation close to the soffit, without worrying about clogging the soffit attic ventilation ports with insulation vent chutes allow for sufficient accumulation of insulation right above where your house ceiling meets the exterior wall, thus limiting air exchange between the living space and the attic  However, your attic ventilation / air [...]]]> Attic Ventilation

Vent chutes that are also called baffles or rafter vents play an important role in your attic ventilation system.

House attic vent chutes and their three important roles in attic ventilation:

  1. Vent chutes provide unobstructed air passage between the soffit vents and the attic
  2. Vent chutes allow installation of attic floor insulation close to the soffit, without worrying about clogging the soffit attic ventilation ports with insulation
  3. Vent chutes allow for sufficient accumulation of insulation right above where your house ceiling meets the exterior wall, thus limiting air exchange between the living space and the attic

Soffit and soffit vents - and important part of attic ventilation which is required for the vent chutes to function

However, your attic ventilation / air circulation can perfectly survive without the vent chutes, in some cases they might be even useless (houses with no soffits or no soffit vents don’t have any use for vent chutes) – it all depends on the design of  attic ventilation and insulation of the attic floor.

Soffit – the exposed underside of the roof section overhanging house wall

So, how do you find out if your attic ventilation is properly functioning and if you need any attic vent chutes?

Unfortunately, you have to have attic ventilation examined (not that this is the only reason to visit your attic periodically). If your climate has a cold season; pick one of the coldest days for this purpose, best if the temperature drops below freezing.

This way, you’ll be able to spot many more attic ventilation problems than while doing it on a warm day. For attic ventilation issues other than vent chutes, please visit the rest of the  house attic problems category posts.

House attic vent chutes come in two popular flavors:

  • cardboard
  • foam (looks like a compressed Styrofoam), and variety of colors.

Most typical attic vent chute sizes are 16″ and 24″ to match open space between the roof framing members.

Vent chutes are shaped in such way that can be stapled to the roof decking along its edges, which is an easy task if installed on a new construction, without the ceiling drywall below.

Attic vent chutes can be also installed by sliding them between the insulation and the roof decking, which might be hard in some cases because of the roofing nails sticking out of the decking, low clearance, and insulation of course.

  • Attic vent chutes are very useful for attic ventilation improvement in attics filled with a blown-in type insulation.

Attic ventilation problems - missing attic vent chutes, insulation blown by air drafts away from the soffit, exposed ceiling below

Improperly installed attic vent chutes compromise attic ventilation and are responsible for mold growth

Blown-in or any loose / poured type of the attic floor insulation isn’t as easy to control as blankets and other compacted / formed into a shape insulation types.

Without vent chutes, the insulation can fall into the soffit compromising attic ventilation, or it is often blown by air drafts from the area near the soffit deeper into the attic. This exposes attic floor and allows warm air from the living area below to migrate into the attic and condensate on the roof decking surface (cold season).

To maintain attic ventilation and prevent such situation from happening short pieces of batt insulation can be placed in the area closest to the soffit, and then filling up the rest of the floor cavity with blown-in type insulation, or by installing vent chutes.

With already installed blanket, batt, rolled type of attic insulation stuffed to far into the soffit you’d need to pull it back into the attic so you have enough room between the roof decking and the insulation for sliding the vent chute into that space.

  • Don’t push the vent chute all the way down into the soffit, this is not necessary, it just has to go slightly deeper than the insulation directly beneath it. After placing the vent chute against the roof decking (staple it if you can), push the pulled insulation firmly back into the space, but without crushing the vent chute.

Attic ventilation – vent chutes in cathedral ceilings

Attic ventilation - cathedral ceiling insulation without required 2 inch spacing to decking and no vent chutes installed (cold climate) often results in mold growth

This attic ventilation subject I’ve already covered in the cathedral ceiling ventilation article. If there are no vent chutes installed and the insulation has been packed tightly into the rafter space, you’ll most likely end up with mold, and not much can be done without serious remodeling.

Bathroom vents discharging into the soffit - air returning into the attic through the vent chute and causing mold growth

In some cases installed vent chutes might create attic ventilation problems – a very common issue is when the bathroom vent discharges into the soffit (International Building Code does not allow it, but some jurisdictions do … for some unexplained reason).

With the attic vent chute installed close to the bathroom vent discharge register, the warm and humid air will always find its way back into the attic and often result in condensation + mold growth.

How many attic vent chutes / rafter baffles do you need to optimize attic ventilation?

If you go to your attic to evaluate attic ventilation and against all odds everything looks perfect:

  • there’s no moisture stains on roof decking and framing
  • no corrosion or roofing nails sticking through the decking
  • no dripping condensation stains on the attic floor insulation
  • no mold residue

you most likely don’t need any vent chutes.

Missing vent chutes compromising attic ventilation and causing mold growth

If you did notice any of the problems listed above, you’d have to start investigating attic ventilation, and attic vent chutes installation might be a way to solve your problems.

You can start from installing them only in the areas where you observed some obvious ventilation issues.

Attic ventilation - properly installed and perfectly performing attic vent chutes 1

Properly installed attic vent chutes improve attic ventilation

You can also fill every single rafter / truss space with a vent chute just to be on a safe side, but before you do that, make sure that your house has a soffit with existing and open vents.

Attic vent chutes installed but soffit vents clogged or non-existing, which resulted in mold contamination

No matter how many vent chutes you’ll install in an attempt to improve attic ventilation, they won’t work if the soffit vents are clogged or if they don’t exist at all – seeing a soffit vent register on the house exterior does not necessarily mean that it is open.

It might be sealed with several coats of paint, clogged with dust / lint, clogged with insulation from attic, or there might be no cut-out above the exterior register – check this first.

Whatever you decide to do, always remember about your safety first!

Do not attempt to do anything you are not felling 100% comfortable with, be extremely cautious on the ladder, always wear protective gear when working in your attic, avoid performing attic ventilation and vent chutes work in hot weather.

Ice Dams and Icicles, Preventing Roof Edge Ice Damming Wed, 31 Dec 2008 02:59:22 +0000 How to prevent roof ice dams formation

Roof ice dams formation along the edges of your home roof and icicles hanging from the gutters and / or soffits should never be ignored. Their beauty on the exterior has roots penetrating your house attic and wall structures, often causing significant damage.

There are three main things responsible for roof ice dams:

  1. Inadequate / improper house attic insulation
  2. Inadequate house attic ventilation
  3. Heat sources in attic area

Roof ice dams and icicles caused by missing wall and floor insulation in attic areaAny areas between the attic and living space that are missing or have a low amount of insulation permit unwanted heat to transfer from the house into the unheated attic.

Warmer air elevates the roof deck temperature directly above the “leak” and causes snow to melt onto the roof surface. Water running down the roof towards the area along the gutters / over the soffits starts re-freezing (soffits and gutters are colder than the rest of the roof surface because they hang over the house edge), creating roof ice dams.

Roof ice dams and icicles caused by missing soffit vents and low attic insulation levelResults of roof ice dams caused by a poor soffit ventilationWater from melting snow and ice forms icicles; some of the water below and above the ice dam will find its way back under the shingle surfaces. If your roof has no ice & water shield installed (older roofs rarely have that), the roof deck becomes soaked with water and eventually mold starts growing on its surface. In some roof / house structure designs, water from the roof ice dams might start dripping into the wall cavity located directly underneath it.

Continuous soffit vent significantly improves attic ventilation and helps preventing roof ice damsRoof - attic power and passive vents help preventing roof ice damsIf you have any heat sources in the house attic like improperly installed bathroom vents, heating ducts, gaps around the attic floor penetrations, etc., you are dramatically increasing your chances for roof ice dams formation.

Properly designed attic ventilation, including plenty of soffit / drip edge vents and roof top vents, may be able to remove the excess of heat and prevent roof ice dams from appearing on your roof. However, by leaving leaks as they are, you are wasting expensive energy.

Snow melting on roof surface due to missing attic insulationObserve your roof after the snowfall. If you notice snow disappearing from the roof surface in certain areas – check the attic. The main problem should be directly below that spot where the snow has already melted. It may take only a little effort to find it, but be extremely careful when evaluating the attic – don’t do it if you are not 100% comfortable with it!

It doesn’t take much snow on the roof to create serious conditions in the attic and roof ice dams on the exterior. If you chose to ignore it, though, it might require a lot of effort and money to fix it.

Roof and gutter heating cables – they help to eliminate roof ice dams, and might be your only solution for some types of roofs. However, if your house has an accessible attic, and poor attic ventilation is responsible for roof ice dams – correct the problem. It might not be cheaper, but it will also help to keep your house cooler during the summer.

Check your attic periodically, if you notice roof ice dams forming along the edges of your roof, that’s where you have to go to fix this problem.

Attic Black Mold and How to Prevent or Stop it from Growing Mon, 15 Dec 2008 23:03:27 +0000 If you had a chance to read “Attic Black Mold and Why is it Growing in Your Attic” (you can quickly watch the short video below), it’s now time to continue attic evaluation.

Attic black mold does not necessarily cause your house environment contamination, but under some conditions it might.

However, attic black mold usually becomes an issue when discovered during the home inspection. In addition, depending on the contamination extent, correcting the problem could make a significant hole in your budget.

In case the black mold has already contaminated your attic, I will show you how to stop it from further spreading. If there is no mold, just follow the same guideline to ensure that everything is the way it should be.

Remember – if you are not sure how to do it – find somebody else comfortable with accessing the attic. It is not worth the risk of getting seriously injured! The best time to inspect the attic and determine if it is functioning properly is during the coldest winter days.

Attic black mold - properly insulated attic access panel

How to prevent attic black mold #1

You should have attic access panel / pull down stairs insulated to minimize air transfer between the living area and the attic. Roof-decking section located above the attic entrance might be your first encounter with attic black mold.

Pre-cut piece of a blanket insulation glued to the hatch will do the job – if it has a paper facing (or any other vapor retarder type), apply paper to the hatch material surface. If using any other materials – make sure that they are not flammable and can be exposed.

For pull-down stairs, people sometimes make a square / hinged / insulated box that opens up into the attic after the stairs are open.

Attic black mold cause - missing kitchen vent section in attic areaAttic black mold cause - missing bathroom vent discharge pipeAttic mold cause - disconnected bathroom vent discharge pipeAll dryer / kitchen / bathroom vents must discharge to the house exterior and beyond the attic area – they are huge sources of warm, humid air, which feeds the attic black mold growth if trapped under the roof.

How to prevent attic black mold #2

If you are looking at the attic section located directly above the bathroom and / or kitchen with an exhaust fan discharging through the ceiling, you should be able to see some kind of a pipe/duct (galvanized steel, aluminum, or plastic – no plastic for the kitchen vent!) between the attic floor and the roof decking.

If there is no pipe, and you cannot see the fan enclosure itself, turn it on before you step into the attic, and try to locate it by following the sound, exhaust fan might be under the layer of insulation.

House attic black mold - bathroom exhaust fan discharging into the soffit causing mold growth on the roof deckingHouse attic black mold - bathroom exhaust fan discharging into the soffit causing mold growth on the roof deckingThere is a chance that vent discharge pipes are in the soffit or connected to the vent ports installed inside the soffit. Personally, I don’t recommend such installations and for one very simple reason – they are often responsible for the attic black mold growth.

During the cold season warm air will return to the attic through the soffit vents (some jurisdictions permit it and even recommend such installation). So, if there’s no pipe attached to the vent, or one discharging through the soffit appears to be causing black mold growth (stains / discoloration above the soffit area where the pipe enters), remove the vent pipe from the soffit.

Extend it through the roof using a dedicated port or at least install it close to the attic vent (just make sure that vent screen is clean).

Attic black mold - kitchen vent must have a dedicated port, attic roof vent should not be used for this purposeKitchen vents should have dedicated ports (don’t use attic ventilation ports), and smooth interior, single wall, galvanized steel pipes should be used for discharge, not plastic or aluminum flexible hoses.

How to prevent attic black mold #3

Disconnected dryer vent in attic area might result in attic black mold growthAttic black mold - lint contaminated dryer vent on roof surfaceA dryer vent discharging into the attic is a huge source of moisture and heat – requires its own dedicated port (just like the kitchen vent). Again, smooth interior wall metal pipe should be used (no plastic permitted and flexible aluminum not recommended).

Dryer vents require periodical cleaning

to remove accumulated lint from interior walls – when it becomes clogged, you’re just wasting precious energy and creating a fire hazard – if it penetrates the roof, it would probably be easier to separate the discharge pipe in the attic area (at roof vent connection) and clean pipe and roof vent screen from there.

Clogged dryer vent pipes overheat and if pipe connections have been sealed / secured with regular duct tape, they might eventually separate. This would allow for warm and moist air discharge into the attic, thus creating a perfect environment for attic black mold. Do not use screws on connections, they simply trap more lint inside, so plastic ties and heating ducts aluminum tape / aluminum foil tape + regular maintenance is the best choice.

How to prevent attic black mold #4

Missing skylight chase walls insulationAttic mold - missing attic floor insulation

Any missing insulation on skylight chases, walls / ceiling between the attic and living quarters should be installed – with blanket type insulation always put moisture barrier / vapor retarder (paper, plastic, aluminum, etc.) facing towards the heated area – never leave flammable paper exposed.

Improperly installed attic floor insulation - exposed flammable paper and double vapor retarderAttic mold - vapor retarder facing should be always applied toward heated areaIf you’re planning to install additional insulation on top of the existing one, make sure that there’s only one vapor retarder – example: if an existing insulation has a paper facing, you should not install another paper faced insulation layer on top of the old one.


Attic mold - open chase around the chimney at the attic floor penetration is a significant source of heat and should be properly sealed

There might be an open chase / empty wall space between the basement / crawlspace and attic area – seal it, from both sides if possible (around the chimney flue pipe – use metal fire-stop/radiation shield and proper clearances to framing and insulation). If it is a duct supplying combustion air to the furnace / utility room containing gas burning appliances – it must remain open and unobstructed.

How to prevent attic black mold #5
Attic black mold - cathedral ceiling insualtion without required 2 inch spacing to decking (cold climate)Attic mold - 2 inch separation between the insulation and roof decking for proper air circulationCathedral ceilings insulation – Cathedral ceilings insulation – it has to be installed with a proper clearance to decking surface (2″). Without that clearance that allows for air circulation, mold might start growing on the roof-decking surface.

How to prevent attic black mold #6

Plumbing vent pipe left open in attic area, and should continue through the roofPlumbing vents terminating in the attic area – extend them through the roof, repair or replace cracked plumbing vent pipes. Sewer gases vapor adds additional unwanted moisture to the attic which can condensate on decking, start dripping onto your ceiling, and become breeding ground for the attic black mold.

How to prevent attic black mold #7

Furnaces and water heaters installed in attic areas should be contained inside a separate and insulated room – code requirement in some jurisdictions. Any vent pipes discharging exhaust gases from the furnace, water heater, fireplace, and passing through the attic area must be double wall / B vent type or sometimes triple wall (manufacturer or local requirement in some jurisdictions).

How to prevent attic black mold #8

Missing, deteriorated insulation on attic installed air ductAttic mold - uninsulated forced air heating system ducts waste energy and release heat into the atticHeating ducts – insulate their surface to help your heating and air conditioning system perform more efficiently. Besides wasting expensive energy, heat released from the air ducts surface might condensate on the roof decking surface and cause mold growth.

How to prevent attic black mold #9

Attic mold caused by leaking roof surfaceLeaking roof – fix it as soon as possible because the mold feeds on moisture, and in this case will grow at any temperature.

And the number 10

I’m listing it as a last item, but it is actually the most important thing that causes attic black mold growth – lack of proper attic ventilation. Make sure that your attic has it and that it is properly balanced. It means that you should have a sufficient amount of attic ventilation ports split 50/50 between the upper and lower portion of the roof.

The above standard might work if everything else is perfect, but in reality, the attic vents will eventually become clogged with lint, insulation, bird nests, etc. When that happens, any combination of the first 9 items from my list increases chances for mold in your attic.

I hope that the above 10 paragraphs will help you to stop or prevent attic black mold from growing. I also highly recommend to check  my other attic black mold concerning posts for more valuable information on this subject.

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What is Attic Black Mold and Why it’s Growing in Your Attic Sun, 03 Aug 2008 17:30:03 +0000 attic black moldThere are actually several different reasons that might be responsible for the mold to appear under the house roof... and sometimes compromise your real estate transaction. That is why attic evaluation and attic mold treatment (if you’re out of luck) should be performed before even putting your house on the market, and on regular basis.]]> attic black mold

That is why attic evaluation (and attic black mold treatment if you’re out of luck) are such an important component of house maintenance and should be performed before even putting your house on the market, and on regular basis.

Why is attic black mold growing under your roof?

Watch Home Maintenance videos on – Black Mold in Attic

Attic black mold caused by inadequate ventilation

In search for attic black mold pictures I went through just a couple of hundreds files from my recent home inspections. And… I’m overwhelmed with a number of homes contaminated with attic mold. While inspecting I’ve never realized that, but this is just another proof that house attic is one of those completely off limits house areas for many homeowners.

Therefore, I decided to bring a little House Attic Black Mold awareness into your daily routines, and hope you’ll find it helpful. You can find more about mold in your house by following this link – household mold , and this post will deal strictly with pointing out conditions responsible for attic black mold growth.

Many factors can cause attic black mold to grow on your roof decking, and unfortunately the only way to find out is to go there. Below are the 10 main reasons responsible for the black mold growth in your attic:

Attic black mold and frost caused by missing soffit vents#1. cause of attic black mold growth in cold climates is an inadequate attic ventilation – check under the “House Attic Problems” category and Roof / Attic Ventilation Inspection post for more details about types of available venting and venting requirements

#2. The reason responsible for attic black mold contamination is improperly designed attic ventilation – a combination of vents that instead of exchanging the air between exterior and interior, they trap, create pockets of “dead air” which condensates on roof decking during the cold season. Attic ventilation design depends on the shape of your roof, its complexity. Some combination of attic / roof vents might work, some will not – if your attic is suffering from improperly designed ventilation, and you don’t know what to do, send me some pictures and I’ll help you with making this decision.

#3. Dryer / kitchen / bathroom vents discharging into the attic are often responsible for condensation, frost and attic black mold growth on the decking surface. Although condensation and frost buildup conditions would only apply to cold climates, all of the exhaust fan types from within your house should discharge to the exterior.

Attic black mold - missing insualtion on the attic floor allows for heat transfer#4. Inadequate / missing attic floor insulation and vapor retarder (moisture barrier) – allows for heat and moisture transfer from your house into the attic area. Bouncing back to the cold climate – it will often result in attic black mold growth.

Vapor retarder definition – it is a  material or system which adequately retards the transmission of water vapor.

#5. Poor / improper cathedral ceiling insulation and skylight chase walls insulation may also be responsible for attic black mold contamination.

#6. Furnaces and water heaters produce significant amount of heat and if installed in a poorly ventilated attic  (not contained within a dedicated  / enclosed area – attic closet), especially in a cold climate, could be responsible for condensation buildup and mold growth.

#7. Plumbing vents open into the attic discharge moisture saturated sewer gases into the attic.

#8. Uninsulated forced air heating system ducts – in cold climates, they waste precious energy and increase chances for attic black mold.

Attic mold - HVAC air ducts and plumbing pipes chase open into the attic. Uninsulated house interior walls allow for temp. exchange, moisutre buildup in cold atticAttic mold - gaps around the plumbing vent stack at the attic floor penetration allow warm air to enter the atticAttic mold - opening in the attic floor continues to the basement allowing house warm air to travel into the cold attic#9. Poorly insulated ceiling penetrations, attic access panels, kitchen soffits open into the attic, etc. It all adds up and the results are sometimes pretty dramatic. I’ve seen chimney and plumbing pipe chaises open at the lowest floor of the house, in a basement or sometimes flooded crawlspace, continuing through the house’s floor or two, and into the attic. Imagine the amount of warm, humid air transferred into the attic space and how much attic mold this can produce.

#10. Leaking roof – mold in the attic caused by the failing house roof protecting surface will be usually concentrated in leakage area and below it. However, poor attic ventilation could significantly accelerate mold growth.

Combining just first two items from the list of t he 10 main reasons responsible for the attic black mold growth could transform your attic into the steamy, mold-contaminated room during the cold season.
Any warm air trapped under the roof will cause condensation to form on framing, decking surfaces, and roofing nails creating mold nesting habitat.

Some homes have more than one attic and upper one, usually located above the bedrooms and bathrooms is always more susceptible of being contaminated with black mold. Warm air from lower parts of the house will naturally rise up, transfer through the ceiling and all its penetrations into the attic.

Attic mold solution has two parts and both should be executed at the same time:

  1. Attic mold removal
  2. Correction of factors responsible for attic mold – without it, attic mold will most likely re-appear within one season

Black attic mold and frost covered nailsBlack attic mold contaminated decking and framingOnce everything is properly fixed, you won’t have to worry about any attic mold growth. However, I still highly recommend to periodically monitor the attic.

Since you already know, why is the black mold growing in the attic it is time to do some investigation above the ceiling. Be extremely careful, if you don’t feel comfortable with accessing the attic, find somebody else to do it for you!

Pictures of mold in attic - roof decking covered with mold Pictures of mold in attic - contaminated decking surface visible directly above the attic access panelPick a cool day for this trip, powerful flashlight and dust mask. Attic access might be as easy as pulling down folding attic stairs, but sometimes it is a challenge as far as size of an opening and its location.

Shine your light beam above your head and onto the roof decking / framing surface, check carefully areas where attic floor meets the roof, because that’s where attic black mold usually starts appearing (samples of what you might see are on the pictures).

If you see no discoloration, clean wood surface with no mold residue on it, than everything should be OK .

Cathedral Ceiling Ventilation | House Attic Vents Tue, 11 Mar 2008 18:32:24 +0000 Depending on your house interior and roof framing design, cathedral ceiling ventilation can be treated as an independent, or attic ventilation related condition. As much as regular attic ventilation is an important part of your house maintenance routine and usually easy to perform, cathedral ceiling ventilation maintenance might be difficult or even impossible to do. Majority of problems with cathedral ceiling ventilation develop in structures where the ceiling framing, and roof framing are the same. What it means, that there’s no accessible attic between the ceiling and roof surface, only narrow, rafter / truss space which should be partially filled with insulation. [...]]]>

How to maintain cathedral ceiling ventilation?

Depending on your house interior and roof framing design, cathedral ceiling ventilation can be treated as an independent, or attic ventilation related condition. As much as regular attic ventilation is an important part of your house maintenance routine and usually easy to perform, cathedral ceiling ventilation maintenance might be difficult or even impossible to do.

Majority of problems with cathedral ceiling ventilation develop in structures where the ceiling framing, and roof framing are the same. What it means, that there’s no accessible attic between the ceiling and roof surface, only narrow, rafter / truss space which should be partially filled with insulation. Sometimes there’s partial attic, and you can see / look into the cathedral ceiling structure from accessible part.

Cathedral ceiling ventilation - attic visible above the ceiling“Safer” (from the cathedral ceiling ventilation point of view) types of cathedral ceilings are the ones, which have a separate from roof framing structure, which allows air to circulate more freely (image). But let’s talk about this first type. Depending on severity of the cathedral ceiling ventilation problem, you may, or may not see its consequences for a long time.

Some of the conditions, you’d be noticing are:

  1. roof surface deformation above the cathedral ceiling section of your house,
  2. moisture stains on cathedral ceiling surface,
  3. moisture dripping from recessed light fixtures or electrical boxes on the cathedral ceiling,
  4. moisture / water stains stains along the top section of the window located in the wall supporting lower end of cathedral ceiling,
  5. dark stains (ghost marks).

Cathedral ceiling ventilation problem 1Cathedral ceiling ventilation problem 2All of the above conditions are curable, but depending on the extent of damage, it might get expensive (lack of proper attic ventilation is a main cause of attic black mold growth and ice damming). Basic principle for cathedral ceiling ventilation is pretty much the same as for any attic with a “twist” to it.

To prevent possibility of moisture condensation, you need constant air movement between the bottom and top of the roof, through the space between rafters / above the insulation layer installed on top of the finished ceiling. “Twist” is for extreme conditions, which in regular attic are easier to spot, and much cheaper to correct.

1. Cathedral ceiling ventilation / insulation

If properly installed between the rafters, on top of the ceiling material (drywall, plaster, paneling sheets, etc.), there should be approximately 2″ of space left above it, which allows air to flow between the bottom and top of the roof. Ideal installation would also include vent chutes / baffles, secured to roof decking, which ensures proper insulation spacing and undisturbed air flow.

Check here your attic insulation amount recommendations.

Contractors who misunderstand principles of proper attic ventilation, never use vent chutes, use more or thicker insulation than required, packing it tightly into the rafter space, blocking completely air flow, and causing… costly “headaches”.

2. Cathedral ceiling ventilation / Roof bottom vents

Because each rafter space is like a small, individual attic, it needs fresh air feed, which in most cases comes from roof overhang – soffit. With a variety of roof soffit designs, it is hard to suggest any particular type of vent, but continues one would probably cover all possibilities and ensure that each rafter space will receive fresh air. If there’s no overhang / soffit, “vented drip edge” can be utilized.

3. Cathedral ceiling ventilation / Roof top vents

Depending on how your cathedral ceiling ends, different types of vents would be required;  if it goes all the way to the roof top / ridge / peak, where other side of cathedral ceiling starts, the only type of vent that should be installed is a ridge vent .

Some roofers prefer static roof louver vents, and if installed between every two rafters, it will do the job – but it doesn’t look nice, especially when you have a long ridge line. If your cathedral ceiling ventilation ports / space between the decking and the top surface of insulation resting on the ceiling drywall is visible from an accessible attic, and there are no obstructions, any type of properly installed attic vent will do, as long as it provides adequate output.

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Attic Ventilation Requirements: How Many Attic Vents Does Your Roof Need? Mon, 10 Mar 2008 02:53:58 +0000 As long as you have an attic (most likely if your house has a pitched roof and none or partial cathedral ceilings), it should be accessible, and periodically checked for any abnormalities. Many of the home owners don’t even realize, that there’s an attic, and how important it is to maintain attic ventilation and [...]]]>

In order to comply with attic ventilation requirements number of attic vents needs to be calculated and strategically installed. This is one of … or rather the most important issue associated with attic area, having huge impact on your house “health” and proper functionality (especially in cold climates).

As long as you have an attic (most likely if your house has a pitched roof and none or partial cathedral ceilings), it should be accessible, and periodically checked for any abnormalities. Inadequate attic ventilation often results in such “abnormal” issues.

Many of the homeowners don’t even realize, that there’s an attic, and how important it is to maintain attic ventilation and control amount of moisture migrating into this area.

Providing attic ventilation by using a combination of various types of attic/roof vents, plays a key role in preventing such problems as attic mold, condensation, and ice damming…

Attic ventilation requirements/ air circulation

So, how much of that air circulating through your attic you really need …

You can find online calculators, to give you the explanation in numbers and I’ll try to add a few words to it.

Basic attic ventilation principal is to keep that unused section of our house as cool as possible – critical condition during the cold season – dividing amount of the roof upper and lower vents 50/50.

Attic ventilation - insulation of unheated attic roof decking is not recommended, and flammable paper facing should be never left exposed

Some of us think absolutely opposite and seal all of the attic ventilation ports, sometimes insulate roof decking, assuming that such action will lower the utility bill. Unfortunately, by doing that, they are creating ideal attic mold growing environment (moist and warmer than exterior). You can partially determine how good is your attic ventilation by examining roof surface during the winter (from the ground of course!).

After some snow accumulates on pitched roof surface, monitor it over the next few days, and if roof remains snow covered, there’s a good chance, that your attic ventilation and attic floor insulation is adequate, and whatever heat is being transferred through the attic floor (house ceiling), and all other penetrations between the house and attic area has enough escape routes.

Attic ventilation and insulation - melting snow above poorly insualted attic section

Any roof surface section, where snow starts disappearing, usually corresponds to a heat source in the attic, or pin-points attic part where the warm air has been trapped, instead of being vented to the exterior. With ambient temperature above freezing, such investigation might not be accurate, and you’ll need to open the attic hatch…

The ideal roof / attic ventilation would consists of combination of vents located in upper section of the attic (ridge vents, turbine, box-shaped or dome static vents, electric motor powered vents), vents installed along the bottom parts of the roof overhang, called intake, or soffit vents, hip vents, and / or gable vents (all of the provided links are just samples, vents manufactured by one company). Roofs with no or very small overhang might be able to utilize “vented drip edge” .

Do not combine attic gable vents with roof soffit and ridge / upper roof vent systems – it will disturb attic ventilation process.

Attic ventilation - damaged roof turbine vent

Attic Ventilation Requirements – How Many Attic Vents Your Roof Needs

  • Industry standard for proper attic ventilation recommends (for no vapor retarder type of attic insulation – no paper, plastic or aluminum layer between the attic floor and insulation layer) 1 sq. foot of ventilation for every 150 sq. feet of attic space divided 50 / 50 between the inlets and outlets.
  • For vapor retarder equipped attic insulation (for example fiberglass blankets/bats with paper facing),  you should have 1 sq. foot for every 300 sq. feet of attic space – assuming that everything else is perfect…

Complexity of some roofs might prevent such installations, and compromise proper attic ventilation, but each of those “unique” designs would have to be examined and discussed separately. Lets assume, that we have as many venting ports as we should (based on simple formula above, and house exterior examination), and that everything was installed the way it should be, without cheating…

Attic ventilation - properly operating soffit vents extremely improve air circulation through the attic

We can only see this element of attic ventilation – roof soffit vent cover, and expect to have an opening behind it. Once installed, it is hard to determine, if the cover has been secured directly over the cut-out in soffit board. The easiest way would be to access attic area, and check for a light shining through the soffit vents, you should be able to see it from access point.

However, in some cases, you might have to walk further from the attic entrance – be extremely careful if you decide to do that, use good lighting and watch your steps, because most of the attics have no floorboards installed, and you have to step on framing members.

If roof soffit vents are visible on the exterior, but you can’t see any light shining through them, your attic ventilation could be suffering, and you can expect that:

roof soffit vents are clogged with dust or several coats of paint (they should be cleaned if possible or replaced)

Attic ventilation / air circulation - vent chutes / baffles help to transfer fresh air from the soffit into the attic

Attic ventilation - vent chutes / baffles prevent soffits from being clogged with insualtion

roof soffit vents are sealed with attic floor insulation, so called – vent chutes / baffles correct this problem, and they should be installed in rafter / truss spaces corresponding to soffit vents on exterior, or in all spaces (just like on the pictures with black chutes) – they are cheap and more can only do better

roof soffit vents might only exist on exterior – there’s no cut-outs underneath (have some new vents installed or correct current installation to improve attic ventilation).

Compromised attic ventilation - gable vent clogged with birds nest

Attic ventilation / attic air circulation - roof vent clogged with a bird nest

Attic ventilation - two roof vents clogged with bird nests

Most common problem with gable and roof top vents is that they get clogged by bird nests or dust / lint, which compromises ventilation. If that happens, just clean it periodically and if wire screen is damaged – replace it.

Some people install screens on the inside (from the attic), covering cut-out in roof decking board…, it is easier and it does prevent rodents penetration, but it is still great spot for a bird nest.

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Attic Power Vent, Heat and Moisture Ventilation Solution Sat, 09 Feb 2008 01:51:27 +0000 attic ventilationAttic power vent fan blades are extremely sharp! When doing any type of maintenance work around it, make sure that power supply to the motor has been turned off! Most of those attic vents are controlled by a heat or humidity sensing switch and can become active / cause injury while you’re performing maintenance. Humming, muffled noise coming from above the ceiling during the summer is most likely an attic power vent, working hard to pull out hot air from under the roof (attic power vent should be placed close to the roof ridge – top, or installed as a gable [...]]]> attic ventilation

Attic power vent fan blades are extremely sharp!

Attic power vent - gable

Most of the attic power vents are controlled by a heat or humidity sensing switch and can become active / cause injury while you’re performing maintenance.

Roof / attic power vent

Humming, muffled noise coming from above the ceiling during the summer is most likely an attic power vent, working hard to pull out hot air from under the roof (attic power vent should be placed close to the roof ridge – top, or installed as a gable vent).

The most common installations include adjustable thermostat and in some cases humidistat, which activates attic power vent motor accordingly with your preferences (once set, it operates automatically responding to temperature or / and humidity changes).

There are also some devices preset by the manufacturer (usually between 85F – 100F), and attic power vents with no sensor at all, controlled by on/off switch mounted in various location (usually close to the attic entrance).

Attic power vent installation requirements

To serve its purpose properly and save instead of wasting your money, certain requirements for attic power vent installation have to be met:

Single soffit ventTypical soffit ventGable vent sampleThere must be other, adequate number (or more likely square footage area) of ventilation ports installed in lower section of the roof, they are called: soffit vents, if your house roof has an overhang, which extends beyond the house exterior wall, or gable vents – located at the attic area, commonly on the exterior wall where the two planes of a sloping roof join, forming a triangle.

There’s a possibility, that type of your roof allows only for installation of vents on its surface – good examples are hip roofs on many of the Chicago style Georgian type homes, which have no overhang / soffits.

In such case, if the attic power vent has been installed in upper section of the roof, passive vents can be placed not less than 1/3 of the distance between the roof bottom edge and top (ridge), hip / ridge vent system can be installed, or vented drip edge mounted along the roof edges.

Combustion air supply from attic to furnace - utility room must remain open all the timeThe attic floor, and all penetrations between the attic and living area of your house should be properly insulated and sealed. Any gaps, holes, and lack or inadequate number of attic vents will cause attic power vent to create a vacuum, and remove AC cooled air from the house. In some properties, there’s a duct between the attic and utility room, which provides combustion air for gas burning appliances – this one must remain open on both sides (on the picture)!

Make sure that the attic power vent, or its opening is protected with wire mesh / screen – vents are usually equipped with wire mesh that wraps exterior of the fan blades housing, and prevents rodents from accessing attic area (screens installed from attic side allow birds to build nests inside the fan).

However, some of the larger animals are strong enough to penetrate this obstacle, in the process damaging fan blades. Therefore, it’s a good idea to examine your attic periodically. Be careful, most attics have no flooring installed and walking on framing is difficult, if possible, examine fan condition from attic access point.

Before installing a new attic power vent in your attic, make sure you properly calculate square footage area If installed fan is too small, it will have to operate much longer, to move the same amount of air through the attic. Adjusting thermostat too low might cause fan to run constantly during hot summer – try to set the temperature dial to a 100 -110 degrees Fahrenheit.
The fan should start automatically as soon as the attic temperature rises above the preset setting, and cuts off when the attic is cooled down to approximately 10% below the thermostat setting.

Try low voltage, solar battery operated attic power vent – saves money on installation, very quiet, but approximately 3 times as expensive, as a regular attic power vent.