Creating 1" Air Gap between foundation wall and fiberglass batts



We just bought a house in Calgary, AB, Canada and notice that the basement is below grade and is insulated with fiberglass batt. There are no drywalls at the moment; hence, I have access to the vapor barrier and the fiberglass batt. The house is 10 years old and the basement looks dry. I notice that there is no air gap between the foundation wall and the fiberglass batt. Basically, the fiberglass batt is touching the foundation wall and the framing studs are 2x4. I was thinking of putting a 1x6x6 treated wood fence board per cavity box to distance the fiberglass batt from the foundation wall. This is not the best solution but I believe it may be the cheapest and quickest. So one side of the 1x6x6 treated wood would be touching the foundation wall and while the other side will be touching the fiberglass batt. I am hoping that the thickness of the fence board will create the approximately 1" air gap, see attached picture. Please let me know your thoughts and comment. ...

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A building site for a row of riverside apartment blocks in Cambridge. The buildings are being constructed using a systems build with a steel frame and various prefabricated components. The blue plastic on the central building is the vapour barrier for the thermal wall insulation before the exterior cladding has been fixed.

Building insulation materials are the building materials which form the thermal envelope of a building or otherwise reduce heat transfer.

Insulation may be categorized by its composition (natural or synthetic materials), form (batts, blankets, loose-fill, spray foam, and panels), structural contribution (insulating concrete forms, structured panels, and straw bales), functional mode (conductive, radiative, convective), resistance to heat transfer, environmental impacts, and more. Sometimes a thermally reflective surface called a radiant barrier is added to a material to reduce the transfer of heat through radiation as well as conduction. The choice...

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Fill all voids

Fill the stud cavity

Push batts all the way to the back of each stud space and then pull out the front edges until they're flush with the face of the studs.

The key to a quality insulating job is tight-fitting batts that completely fill the stud cavity with no voids or gaps. You can do top-quality work with only a few basic tools. You'll need a utility knife with a good supply of sharp blades, a tape measure and a straightedge, and a 3- or 4-in. putty knife for stuffing insulation around doors and windows. Fiberglass can irritate your throat and skin, so wear protective gear. Buy a two-strap mask rated for fiberglass insulation (look for N-95 rating) and wear a hat, gloves, a long-sleeve shirt and goggles to keep fibers out of your eyes.

Fit batts tightly around electrical cables and boxes

Split batts around cables

Split batts to fit around electrical cables. Tear the batt in half, starting from the bottom. Slide one half...

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Heating and cooling your home sucks more money out of your bank account than any other type of energy consumption (unless you live in a high performance home, in which case the proportions are different but the total is smaller). The building envelope, which comprises insulation and an air barrier, controls the flow of heat between inside and out. A good building envelope is the first step to keeping heating and cooling costs low. (Well, OK, good design is the first step. You're right.)

Not all types of insulation are equal. Insulation is rated by R-value, but just putting R-13 insulation in your walls is not a guarantee that it's performing at R-13. That's why RESNET came up with a method for grading the installation quality of insulation, with grade I being the best and grade III being the worst.

Fiberglass batts often result in a grade III because the contractor fails to take the time and effort to install them properly. Batts can achieve better grades when...

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Editors Note: This article is from 2009 when Fred & Kim were getting ready to insulate their basement, and it’s a great review of the options they considered. If you’re thinking about insulating your basement, it’s important to make an informed decision about installing a vapor barrier, and there’s a lot of misinformation out there. After you finish reading this article about insulation options, be sure to check out the Related Content section to learn more about vapor barriers.

We’re just about ready to insulate an unfinished basement game room and this post reviews a number of options for achieving maximum efficiency in basement insulation installations. The article begins with an overview of the basement area and then provides a summary of insulation options.

Basement Wall Construction &...

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A selection of insulation materials can aid in building insulation. All of these are based on standard principles of thermal insulation. Materials used to reduce heat transfer by conduction, radiation or convection are employed in varying combinations to achieve the desired outcome (usually thermal comfort with low energy consumption).

Choice of insulative material

The choice and degree of insulation is based on a number of factors:

Prevailing climate. Ease of installation e.g. some materials cannot be retrofitted due to issues of accessibility or toxicity Durability - resistance to compression, moisture, degradation Cost - which is generally related to durability and effectiveness The mode of heat transfer - bulk insulators are most useful in cold conditions where significant convective / conductive losses occur, they are less useful in hot conditions where solar radiation is the source of heat gain. (see Building insulation)[dubious – discuss]...
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Insulation is used in a variety of locations in houses: inside walls and roof systems, under floors, and around foundations. Water heaters and ductwork are also commonly insulated. Insulation is required in warm climates to keep the heat outside and in cold climates to keep the heat inside. There are a variety of different types and forms of insulation available. Some are suited for use in specific parts of a house. Nearly every type of insulation has been implicated in some health problem yet, with care in installation and material selection, a healthy house can contain insulation. (This article is from the archives of the original Healthy House Institute, and the information was believed accurate at the time of writing. From "The Healthy House: How to Buy One, How to Build One, How to Cure a Sick One" © 2000 by The Healthy House Institute).


All materials resist the flow of heat to some degree. Dense, solid materials such as steel and concrete resist the...

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When asked to describe characteristics of an energy-efficient building, most might list the following: well-insulated walls, a ventilated roof with a thick layer of insulation over the ceiling, quality windows with low-E glass, and a high-efficiency heating and cooling system. Surprisingly, many buildings with these features experience higher than anticipated utility bills, elevated levels of moisture or indoor air pollutants, and premature deterioration caused by moisture accumulation in walls and roofs. Why is this happening and what can be done to avoid these problems?


RULE #1: Seal all joints in the building shell. It doesn’t make sense to invest in well-insulated walls and ceilings yet do little to block air flow around and through the insulated cavities. Wood-to-wood and drywall-to-wood joints in the exterior shell of a building are not airtight and should be sealed with gaskets, foams, caulks, or air barrier films. The...

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Quick Column Summary:

Tar paper or 6 mil plastic vapor barrier Leave an air gap to avoid mold Video link

Charles Gregoire is perplexed up in Ottawa, the capital of Canada.

"Confusion on whether to use tar paper or 6 mil plastic. In repairing a 64" section of an existing basement interior wood framed dry walled wall I discovered tar paper was glued onto the concrete wall, followed by a 1/2" gap, 2x3 wood framing followed by clear plastic vapor barrier and drywall.

Here's Charles' wall.

After ripping everything out I needed to restore the section of wall. Note that there was concern over damage/mould from a plumbing leak that occurred 3 years prior. After ripping the section out I concluded there really wasn't any issue.

The fiberglass insulation was a slightly damp to the touch. I ran into some confusion when try to decide how to restore the wall section. After watching many videos and talking to people at Home Depot and Lowe's I never gain an in...

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Basement Space Offers the Best Value

The best part about choosing to renovate an unfinished basement is your savings and the return on investment (ROI). Finishing the basement is the least expensive method of adding usable square footage to your existing home, because the structure is already in place. According to the Remodeling 2010–11 Cost vs. Value Report, national averages suggest that at resale you might expect to recoup 70% of the total job cost of a professional basement remodel. Although this percentage of cost recouped is not as high as it has been in years past (90% in 2005), it does present a higher current return on investment (ROI) than the more expensive family room addition (62.5% in cost recouped).

Moisture and Air Sealing

First things first: most homes are constructed over one of two types of foundation, masonry or poured concrete. The number one problem affecting a finished basement is moisture; thus the most critical step in finishing a...

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A gut rehab on an old home usually means opening up the walls from the interior so that new wiring, new plumbing, and new insulation can be installed. Uninsulated walls are common in older homes, so it’s no surprise to see empty stud bays. But in some older homes—those without any sheathing—you’ll be looking right at the siding. How do you insulate stud bays from the inside if the building has no wall sheathing or water-resistive barrier (WRB)? There are two basic approaches, and they start with creating an air gap between the back of the siding and the cavity insulation you plan to install.

Using air-permeable insulation with rigid foam
If you plan to fill the stud bays with airpermeable insulation (fiberglass batts, blown-in fiberglass, mineral wool, or cellulose), the material you use to create the air gap needs...

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Cut batts to the appropriate height.

You should have purchased insulation of the appropriate width, but you'll have to cut it to size for every space you want to fill, in terms of height. Lay the insulation out, then carefully use your utility knife to cut through the face (if you've purchased faced insulation). It's kind of hard to cut through the insulation itself, which has the consistency of tenacious cotton candy, but you can pull it apart once you get it started.

When you get your insulation home, keep it wrapped up until you're ready to use it. Cutting fiberglass insulation sends lots of little fiberglass particulate up into the air, which can cause allergic reactions and breathing problems. It's also extremely itchy, and can cause rashes in some people with sensitive skin. Never touch fiberglass batting with your bare hands and always wear breathing equipment when handling it. If you come into contact with fiberglass insulation, don’t scrub your hands or face with...
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Hello everyone,

Let me start off by saying I have no clue what i’m doing. I decided to finish a rec room in our basement. This is an old house with concrete block walls that were previously painted with latex paint.

I went to lowes and asked a random person about what type of insulation I would need. He suggested faced batt and then asked if I had put up a vaper barrier between the wall and the frame. I said no but if that is the best way to go I can still do that without too much trouble. Long story short, here is my current setup which after looking on the internet seems to be a terrible one.

I wrapped the back, sides, top, and bottom of my frames with plastic sheets I got from lowes. I have the frames directly against the concrete blocks. I then added the r-13 insulation with the paper facing the inside, and drywall over top. so from inside out I have drywall, frame/insulation, plastic sheet, block wall.

The basement is fairly dry. The few spots...

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Rigid foam can be used in walls, roofs, and foundations, for retrofits or new construction. Most varieties of foam have a higher R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. per inch than fiberglass, cotton, or cellulose.

There are three main types of rigid foam insulation: expanded polystyrene (EPSExpanded polystyrene. Type of rigid foam insulation that, unlike extruded polystyrene (XPS), does not contain ozone-depleting HCFCs. EPS frequently has a high recycled content. Its vapor permeability is higher and its R-value lower than XPS insulation. EPS insulation is classified by type: Type I is lowest in density and strength and Type X is highest.), extruded polystyrene (XPSExtruded polystyrene. Highly insulating, water-resistant rigid foam insulation that is widely used above and below grade, such as on exterior walls and underneath concrete floor slabs. In North...

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By Todd Fratzel on Insulation

Spray Foam Insulation for Basement Walls

I’ve written quite a few posts on Insulating Basement Walls using rigid foam board insulation. In this article I’d like to share several other sites that discuss using spray foam insulation for basement walls. Spray foam insulation is in my opinion the best option for basement walls if you can afford it.

Evaluating Insulation Options

Fred over at One Project Closer is preparing to insulate his basement in preparation for a new finished family area. He has written all about his Basement Insulation Options including his selection of spray foam insulation.

Spray Foam Insulation Examples

Two of the house blogs that I read have both featured recent basement insulation projects that used spray foam. Shane over at Shane and Casey has been working on insulating his basement with spray foam. Shane is using a hybrid approach of 1-inch spray foam to seal things up followed by...

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