Know your insulation

You can use foam to seal air leaks in a number of areas around the home, such as where the sill plate sits on the foundation, behind baseboards and window trim, and wherever pipes or wiring breach exterior walls.

Polyurethane is the denser of the two and has a slightly higher R-value (five versus 4.5 for latex). Overfilling cavities can lead to bowed frames or cracked windows. Choose the formulation based on the job and size of gap you need to fill.

A 340-gram can of either yields a 1/2" bead about 200' long and sells for $6 to $8.

Spray It
Spray-applied foam insulation installation is a job for licensed professionals. There are two types of spray foam, polyurethane (the same material as the stuff in a can) and polyicynene (sold under the brand name Icynene).

Both can be used in retrofits where no insulation exists: small holes are drilled in a wall and the two-part epoxy is injected into the wall cavity. They're also used as an insulating air barrier in attics or wall cavities in new construction. While significantly more expensive than batts or boards, the cost is offset by long-term energy savings.

Polyurethane, with an R-value of six per inch, is also a good option for crawlspaces. Installers spray the sticky foam directly to the underside of the sub-floor. Polyurethane acts as its own vapour barrier and, at least anecdotally, seems to be rodent-proof.

Icynene has a lower R-value (R-3.6 per inch) but contains no CFCs or HCFCs.

On the Loose
Loose fill, or blow-in insulation is another job for the pros. Like batts, it can be made of fibreglass or mineral wool. There are also cellulose (paper-based) products. All have R-values around three to four per inch.

Loose insulations are another good option for hard-to-access areas such as attics and uninsulated wall cavities. Settling can be a problem with loose fill insulation in walls where, over time, it can sink to the bottom-leaving uninsulated voids at the top of walls. The main problem in attics is uneven distribution.

HEALTHY HOUSE
Asbestos and urea-formaldehyde Foam Insulation (UFFI) are two names that can strike fear in the hearts of homeowners. More recently, some vermiculite (loose fill) insulation has also come under scrutiny. A brand named Zonolite, sold in Canada until 1984 and used for retrofit attic insulation, may be contaminated with a carcinogenic form of asbestos.

The good news is that if you leave these types of insulation alone, they'll return the favour. Current research shows the health risks only materialize when these materials are disturbed and particles are dislodged and become airborne.

In fact, Bill Crawford of the Canada Mortage and Housing Corporation says you should take precautions with all types of insulation. “It doesn't matter if it's asbestos or fibreglass or mineral wool, you don't want to go messing around with this stuff. They all have small fibres that can get into lungs,” he says.

If you are planning on doing renovations and are concerned that asbestos or UFFI may be present, get an inspection before you begin. You can find contractors in the Yellow Pages under “Asbestos Removal.”