Do It Yourself: Wall insulation important in all climates

Q. How important is wall insulation? I live in a house built before World War II and a contractor who did some work on it told me there is no insulation in the walls. I’ve read a lot about attic and floor insulation but little about walls. What should I do?

A. Wall insulation is quite important. The Oak Ridge National Laboratory (www.ornl.gov) recommends R-13 or R-15 wall insulation in new homes even in warm climate regions, and considerably more in colder climates (fiberglass batt insulation, often used in walls, has an R value of just over 3 per inch).

But owners of older houses often face a dilemma. Many houses built before the so-called energy crisis in the 1970s, and some built years later, had little or no insulation. Attics and floors are relatively simple to insulate, and many owners of old home have done that, but walls are a different story.

If you have a wood-framed building, there are a couple of approaches that could improve the energy efficiency of exterior walls at reasonable cost. If you have a masonry building, there just isn’t much you can do to insulate that is practical and cost-effective.

At its Energy Star site on the Internet (www.energystar.gov) the U.S. Environmental Protection Agency offers a map and chart showing the recommended insulation levels for retrofitting attics and floors of existing homes in various climate zones.

Wall insulation is not included in the chart, but is discussed briefly in a footnote. According to EPA, wall insulation is best added to an existing wood framed building if new siding is being installed. The recommended procedure is to drill holes in the existing sheathing, blow insulation into the wall cavities (usually cellulose but sometimes fiberglass or foam). Next, insulated sheathing with a rating of at least R-5 is added to the exterior, followed by the new siding.

Some insulation contractors do the first step only – drilling holes in the existing siding, blowing insulation into the wall cavities, then patching the holes. Some wall cavities have so many obstacles inside (braces, pipes, wiring) that the effectiveness is sometimes questionable).

Before attempting to insulate any existing wall, you should have several experienced insulating contractors check the walls and give you estimates of costs and probable energy savings. If you decide against insulating, there are some steps you can take to improve your wall energy efficiency: Installing tightly sealed, energy-efficient windows is a big help, since much of the heat loss through walls goes out windows. Doors should be well weather-stripped, and any cracks sealed.

Q. We have a beautiful ceramic-tile floor in our kitchen, but the chairs to the breakfast bar have metal legs and are quite heavy. When we move the chairs, we worry about scratching the tiles and it also makes an awful screeching noise. How can we fix this?

A. You should be able to attach glides to the chair-leg bottoms. That should make the chairs easy to move and probably also eliminate the noise.

Glides, also called feet, caps, pads and skids, are available for almost any type of chair. Check the bottoms of the chair legs to see if there are already small holes, either threaded or not threaded; some of the best and most-permanent glides attach with small bolts or screws.

If there are no holes, you can either drill them or choose another type of glide. For example, some have sleeves that slip over the bottoms of the legs. Other glides can be glued in place. If you can’t find what you want at a local home center or hardware store, visit www.allglides.com on the Internet to see a variety of types. For a larger selection, search the Internet with the words Glides for Metal Chair Legs.