Even those who live in denial that winter is coming are going to have to admit that the time to dig out warm coats and fire up our furnaces isn’t too far off.
That means that higher heating bills aren’t far off either. As heating costs are your largest home energy expense, why not make this the year to increase your insulation.
A well-insulated house is like dressing for the weather. A wool sweater will keep you warm if the wind isn’t blowing and it’s not raining. On a windy, rainy day, wearing a nylon shell over your wool sweater helps keep you dry and warm.
A house is similar. On the outside, underneath the brick or siding, there’s an air barrier that does the same thing as the nylon — it keeps the wind from blowing through. Then there is the insulation (like your sweater) and a vapour barrier that helps keep moisture away from the house structure where it can do damage.
Canada Mortgage & Housing Corp. offers a comprehensive fact sheet on insulating your house (http://www.cmhc-schl.gc.ca/en/co/grho/grho_010.cfm#cont)
Here’s a few excerpts:
SIGNS OF INSULATION PROBLEMS
In the winter — cold walls and/or floors, high heating costs, uneven heating levels, mold on walls.
In the summer — uncomfortably hot inside; high cooling costs, ineffective air-conditioning system, mold in basement.
R values and their metric equivalent, RSI values, are a way of labelling the effectiveness of insulating materials. The higher the R value or RSI value, the more resistance to the movement of heat.
There are numerous types of insulation such as batt, loose, board stock and spray. Choosing the appropriate type to your specific need is important.
Installation also plays a large role in its effectiveness. Compressing insulation, leaving air spaces around the insulation and allowing air movement in the insulation all reduce the actual R value of the insulation.
The attic is often the most cost-effective place to add insulation. Usually, a contractor blows loose fill into and over the top of ceiling joists. For the do-it-yourselfer, batts laid sideways on existing insulation are an easy alternative. The air barrier at the ceiling line must be tight to ensure warm moist air from the house doesn’t get into the cold attic and condense in the winter. Check ceiling light fixtures, the tops of interior walls and penetrations such as plumbing stacks for air leakage. Ensure that soffit venting is not blocked by added insulation; baffles may have to be installed.
Basement walls are unique because they must handle significant moisture flows from both inside and outside the house.
Exterior insulation is the preferred method from a building science perspective. Insulate the wall on the outside with rigid insulation suitable for below-grade installations, such as extruded polystyrene or rigid fibreglass. This works well with damproofing and foundation drainage as rigid fibreglass or mineral wool acts as a drainage layer, keeping surface and ground water away from the foundation. Basement walls are kept at room temperature, protecting the structure, reducing the risk of interior condensation and increasing comfort.
Interior insulation can also be used. When finishing the basement, use batt insulation in stud cavities or extruded polystyrene and strapping on the face of perimeter walls. If the basement won’t be finished, then install rolls of polyethylene-encapsulated fibreglass over the wall. Never apply interior insulation to a basement with moisture problems. Fix the moisture entry problems before insulating (see CMHC’s publication A Guide to Fixing Your Damp Basement).
Insulate and keep the heat in.
Doug Wastell is president of the London Home Builders’ Association