Insulating basement walls
( NC)— To improve energy efficiency, Hydro-Québec strongly recommends insulating basement walls.
Adding insulation to the uninsulated, semi-insulated or unfinished walls of a home basement can help achieve thermal resistance up to RSI 3.7 and save a lot on heating: up to $ 375 per year for a house with a basement that was not insulated.
It is also possible to save a great deal on heating by insulating the roof crawlspace.
This table shows the potential savings for a 84m2 wall insulated to RSI 3.7.
* Minimum insulation values. The savings correspond to the difference in insulation between this value and the maximum value of RSI 3.7.
Advantages of insulating basement walls
• Insulation increases comfort by reducing or eliminating cold drafts in the walls and the feeling of being cold in winter.
• Insulation also reduces condensation on the inside surface of basement walls.
In an existing building
• Usually insulation is applied from the inside, using insulation that comes in batts or rigid insulation board.
• A vapor barrier must be installed inside and rigid insulation board must be covered because of its flammability.
For new buildings
• It is recommended that basements be insulated from the outside using rigid insulation board to protect foundation walls against the fluctuating thermal stresses to which they are exposed.
• Before starting the work, make sure there is sufficient earth covering the outside of the foundations to protect the footings from frost.