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Q: What are some tips for insulating an older home?

A: Here in the Pacific Northwest, there are many exquisite old Craftsman-style houses, many of which have been standing for a century or more. Older homes have a particular charm and elegance, but keeping an old house warm can be tricky.

Houses built before 1940 were not typically insulated, and the building materials used back then tended to settle or deteriorate over time, which allowed heat to escape and cold air to get in.

Old houses can lose heat from the walls, the roof and the attic floor. Fortunately, there are now numerous energy-saving, cost-effective thermal insulating options.

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Inspect your home

Start by checking to see if your older home has insulation. It’s usually pretty easy to tell in a home’s attic, where you’ll see exposed sections of colored fiberglass insulation or loose fill pieces between ceiling joists.

Also, check your exterior walls for a series of patched holes. This is a telltale sign of blow-in insulation.

Check around your home to see where you may be losing heat. Are there air leaks through cracks around windows, ducts or electrical outlets? Chimneys and fireplaces without working dampers can also be culprits.

Often, the primary site of heat loss is through the top of the house. Because hot air rises, you will lose heat through the roof if it is not adequately insulated.

Choose your insulation

Modern building insulation is classified into four general categories: loose fill, which can be cellulose, mineral or glass fiber; batts, which contain fiberglass, cotton or various wools; rigid boards composed of plastic foams or glass fibers; or expanding sprays.

Blown-in insulation is used in existing wall spaces, and batts are used in unfinished walls, floors and ceilings. Rigid insulation is used in masonry walls such as foundations and unvented low-slope roofs.

The most common insulation retrofit for old houses is loose fill because it can reach places where it is difficult to install other types of insulation.

A qualified professional can help determine which kind of insulation retrofit would work best for your old home.

Since warm air rises, insulating the attic is a good place to start. If the attic is unfinished, the insulation should be placed on the floor.

If your attic is used as a living space, home office, playroom or spare bedroom, the insulation should be placed between the rafters.

There are a number of environmentally friendly insulation products on the market. Blown-in cellulose insulation made from 100-percent-recycled newspaper and treated with borates for fire-resistance and protection against insects is labeled by the Environmental Protection Agency for effectiveness against termites, cockroaches, ants, earwigs and many other pests.

In addition, this product contains no free formaldehyde, no ammonium sulfate, no fiberglass and no asbestos.

Polyisocyanurate, another green insulation product, provides an effective moisture barrier when used with laminated aluminum-foil facers in masonry cavity wall applications.

A relatively new product you may have heard about is cotton insulation made from recycled denim. It is also treated with borates to keep insects away.

HomeWork is the weekly column by the Master Builders Association of King and Snohomish Counties’ Remodelers Council about home care, repair and improvements. If you have questions about home improvement, send them to