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COLUMN: Old homes – improving the building envelope

As the cold weather hits, those of us living in old homes inevitably wonder what we can do to stay warm this winter while not breaking the bank.

One of the best places to start in the quest to make your home more energy efficient is completing a home energy assessment.

One of the best places to start in the quest to make your home more energy efficient is completing a home energy assessment.

Some home owners may already know where the best place to start is, while others may feel its best to bring in a professional. Efficiency Nova Scotia, funded by Nova Scotia Power, offers home energy assessments for only $99. The catch is this discounted rate, is only available if your home is electrically heated. If you get heat from another source, a home energy assessment will run you in the range of $375.


Available Rebates for Upgrades

For electrically-heated homes, Efficiency Nova Scotia will help cover the cost of certain upgrades, offering up to $5000 in rebates or low interest financing up to $25,000. Check out the following website for more details: The Clean Foundation and Efficiency Nova Scotia also offer a Home Warming program for low income home owners. This program, funded by NS Power and the government of Nova Scotia, offers free energy efficiency upgrades to qualifying households regardless of how the home is heated ( Heating & cooling a home can account for more than 60% of total energy costs and Efficiency Nova Scotia reports homeowners whom complete a home energy assessment typically save $800/year.


Adding Insulation - Walls

Adding insulation will likely give you the biggest bang for your buck when upgrading the envelope of your home. Without insulation, a typical home can lose up to 80% of its heat through the walls, roof, and floors. When deciding where to add insulation, it’s good to know what you already have in place and then target uninsulated areas with the largest square footage (in most cases the walls). There are three ways to insulate your walls: 1) blow-in-insulation, 2) remove & replace interior walls, and 3) add to exterior walls. You can save money by combining insulation work with other planned projects. For example, if you are already planning to add new siding that is the ideal time to install exterior wall insulation. Or if you are looking at doing some interior home renovations, this would be the best time to rip down old plaster and install new wall insulation covered by drywall. If you don’t foresee any renovation projects in your future, blown-in insulation is probably the most cost efficient way to go. In all cases it is important to find a reputable contractor who is knowledgeable in building code requirements and understands the proper use of vapour barrier and how to seal joints.

Basement Insulation

Many basements in old homes have no insulation so offer significant potential for improvement. Heat loss around basement windows, cracks in the foundation, or leaks around the sill (joint between foundation and floor system) are likely. Consider installing basement insulation in conjunction with other projects such as water proofing or refinishing the basement. If there is a significant source of water entering your basement the solution may involve excavating around the exterior, waterproofing and installing drainage. At this time insulating your basement from the exterior makes sense. If you are considering insulating from inside, rigid plastic board, polyurethane spray, or a combination of both, are good options. Repairing any cracks in the foundation and sealing leak around the sills should be done before insulating from within. Existing water pipes, air ducts or electrical panels can complicate the process of installing insulation in the interior of your house. Ensure water pipes are located on the warm side – move them if required and install insulation and vapour barrier behind them. Check for proper clearance from furnaces and/or flue pipes to prevent fire hazards.


Attic Insulation

Most likely you already have insulation in your attic however, having a contractor take a look at the amount as well as any potential moisture issues is not a bad idea. Moisture can enter the attic from the exterior or interior and can reduce the effectiveness of insulation and lead to mold or structural issues. When working in the attic do not disturb old vermiculate insulation, breathing it in can be a hazard to your health. Attic venting should be inspected to ensure it is adequate for the space and not being blocked. As long as moisture is not an issue it is ok to simply add new insulation over existing. Batt or blown-in insulation, or a combination of the two, is most common in attics. Proper shielding should be used to maintain a minimum distance of 3” around any metal chimneys to prevent fire hazards. Care should also be taken working around electrical installations, including recessed lighting, to prevent fire hazards.


Windows and Doors

You can help stop heat loss around windows and doors with caulking and weather stripping. If a window or door area seems particularly cold it may be worthwhile to remove the trim, insulate and apply red technical tape around the frame before caulking. When purchasing weather stripping look for high-quality, durable products, especially for doors that will be most subject to wear and tear. In some cases, the additional of storm windows or even replacing doors and windows with new ENERGY STAR® qualified products is advised and will greatly improve homeowner comfort.


Stopping the Leaks

Air leakage through the building envelope can be a major source of heat loss. Since warm can carry large amounts of water vapour, air leaks can cause moisture damage in the building envelope. In old homes, the only vapour barrier is typically plaster walls coated with paint. I’ve done renovation jobs where after removing several layers of wallpaper there were large gaping holes in the plaster, especially on exterior home corners. Cracked plaster ceilings are another common source of heat loss. Sealing up any holes in plaster walls or ceiling, including caulking around baseboards, lighting fixtures and electrical outlets is a good place to start.


Natural Resources Canada offers a great website called “Keeping The Heat In” for homeowners interested in learning more about the basic pricipals of building science as related to home retrofit projects ( Next week I will talk more about improving the mechanical systems in your home to help keep the costs down.


Remember to look for my column in The News every Tuesday, I will be addressing a wide-range of home-related construction and maintenance topics. I welcome readers to submit questions by sending me an email at or call me at 902-695-5919.


Leonard Thompson is a Red Seal Carpenter and owner of MacGibbons Contracting Ltd. In Stellarton.

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