Insulation is a thermal barrier that we place in the exterior walls and ceilings of our homes to preserve the temperature of our conditioned air. In summer it keeps our home cooler than outside and in winter it keeps us warm.
THE "R" NUMBER
For convenience, the different thickness of insulation have been given a rating of resistance. This is referred to as the "R" value. The larger the number, the better the insulation factor. For example, a fibre glass batt of 3 1/2 inches will have an R value of 12, and the same material at 5 1/2 inches has a value of 20. Not all materials have the same insulating value so it is important to note that the same thickness of two different insulating materials may not have the same R value.
- R40 in ceilings (except for electrically heated homes which should have R47)
- R12 on exterior basement walls.
TYPES OF INSULATION
- Fibre glass (batts or loose fill)
- Vermiculite and wood shavings (commonly found in homes built before 1960).
- Foam. (Urea Formaldehyde and Polyurethane).
- Insulation is usually installed in the wall cavities and the attic area when the house is being built. This is the most convenient and cost-effective way of installation. Doing retrofit insulation may mean exploring several different methods and deciding on which method is most desirable to you based on the time and money you may wish to invest.
- Upgrading insulation in the attic is the most common task undertaken. This is probably the easiest type of insulation retrofit. Usually the insulation is blown in on top of the existing insulation to the desired R value. Blown insulation is usually quicker and cheaper to do than other types.
- Adding insulation to the walls is more complex. If you wish to have it put into the wall cavities it will require either removing the wall panels on the outside or inside and manually placing insulation in the voids, or drilling holes in the walls in order to blow insulation into the space between the wall studs. The most desirable method for most people is to install insulation sheet materials to the exterior usually when replacing or upgrading the exterior siding.
- Adding insulation is only the beginning to create a warm (or cool) atmosphere in your home. It is not sufficient to add insulation values to the walls and ceilings if the cold drafts can bypass those areas and infiltrate your home through drafty windows and doors. Caulking and weather-stripping is also necessary to prevent air leakage into and out of your home.
- Ventilation and vapour barriers are also important when considering insulation. Wet insulation loses its effectiveness very quickly. Vapour barriers, which are installed on the "warm" side of the insulation inhibit moisture-laden air from the interior of the house migrating through the walls and getting the insulating material damp. Proper ventilation on the "cold" side of the insulation will quickly dry up any moisture that does get through before it can cause any harm.