Keep the Heat in Your Home

How Super-Insulating Your Attic Can Save Energy — and Money

Many Canadians are doing everything they can to cut down on the amount of energy used around the house. One of the best ways to do this, while also reducing your environmental footprint and lowering your monthly utility bills, is by ensuring your attic is well insulated.

Adding insulation to an attic is a lot like putting on a hat when it’s cold outside. Insulation helps keep the heat inside the home where it belongs, so you can stay warm and cozy without spending a fortune. Insulating and air sealing an attic can also help prevent icicles from forming at the roof edge.

To help save money while keeping your home warm in the winter and cool in the summer, Canada Mortgage and Housing Corporation (CMHC) offers the following tips on how to super-insulate your attic:

• First, create an air barrier by having all gaps and holes that pass through the ceiling into the attic sealed. A good air sealing job will help prevent warm, moist, house air from escaping into the attic. This is a very important first step to any attic insulation project. Ceiling electrical boxes, exhaust fans, pot lights, wiring and duct penetrations, attic hatches, vent pipes and chimneys are locations that should be inspected and properly sealed. 
• If you don’t need frequent access to your attic and if space permits, consider having at least a 71-centimetre (28-inch) layer of blown-in or batt-type insulation added over top of existing insulation. Make sure the new insulation does not block the ventilation spaces needed to permit air to move freely from the eaves into the attic. Insulation dams or guards can be installed to ensure this ventilation space does not become blocked by the new insulation.
• In restricted spaces, such as the eaves where the roof passes over the exterior walls, spray foam insulation may provide a better air seal and insulation level than can otherwise be achieved with batt-type or blown-in insulation. Spray foam insulation can also help prevent “wind washing” of the insulation in this area which can reduce its insulating value and create cold spots along the ceiling-wall intersection below the attic.
• To stop heat from escaping through the attic hatch, insulate the hatch with RSI-5.3 (R-30) or similar high-R-value solid board insulation. Add compressible weatherstripping and a couple of latches to the hatch to ensure an airtight seal.
• If you think you will need access to different parts of your attic, have planks installed through the roof truss members above the insulation layer to provide a surface to crawl over.
• In some cases, due to the condition of the roof, limited space, or a desire to change the appearance of the house, it may be possible to install a new roof over top of the existing roof. This can provide an opportunity to add more insulation than would otherwise be possible.

For more information

For more information on how to insulate your attic, visit our website at www.cmhc.ca or call CMHC at 1-800-668-2642. For over 65 years, Canada Mortgage and Housing Corporation (CMHC) has been Canada’s national housing agency, and a source of objective, reliable housing information.

Published: November 14, 2013