Do It Yourself: Installing reflective insulation in the attic

By Gene Austin
Saturday, June 12, 2010

I want to install reflective insulation in my unfinished attic. Can I do this myself?

-- P. La Pella

Reflective insulation or radiant barriers can be installed in some attics by do-it-yourselfers. Whether it is practical for you to install the material depends largely on the construction of the attic. Installations are simplest in attics with rafter construction, a strong supporting structure to move about on, good access and a reasonable amount of headroom.

Installations in attics with truss construction are more difficult because the cords or "web" in the trusses block easy movement and the base might not easily support your weight. Improvements in attic ventilation systems might also be needed. If you buy a radiant barrier, make sure it comes with installation instructions, since methods might differ among products.

Radiant barriers are simply sheets of material, often plastic, with a reflective surface on one or both sides. Some radiant barriers are perforated to let moisture pass through. One way to install a barrier is to staple it to the inner surface of the roof rafters. Another is to spread it over existing insulation on the floor. The barrier works by reflecting heat from the sun away from the living area, reducing solar heat gain. Some barriers are also designed to prevent heat loss from inside the building during the heating season.

Many experts say radiant barriers work best in warm, sunny climates and are less effective in colder climates where cloudy weather is common. Field tests by the Florida Solar Energy Center showed cooling-cost savings of 2 to 17 percent, depending on a number of factors including the amount of conventional insulation. I have seen no definitive estimates of heating-cost savings.

A radiant barrier should not be considered as a substitute for conventional attic insulation; it is a supplement only. There is a great deal of information available on radiant barriers, and one of the best sources is the U.S. Department of Energy. For more information, check, which is operated by the department. Search using the words "radiant barriers." Another good source of information is

How can I remove the adhesive left by old window film? -- L. Martin

Gila Films, a leading manufacturer of window films, recommends a solution of 8 ounces water, 4 ounces ammonia and 1 teaspoon of liquid dishwashing soap. Put the solution in a spray bottle. Gila also makes a ready-made solution. Protect the windowsill and floor so no solution or adhesive can drip on it. Spray the adhesive thoroughly with the solution, and rub it in with an old towel until the adhesive turns milky white, then scrape off the adhesive with a razor-blade scraper or single-edge razor blade. Keep the blade clean by wiping it frequently and replace it if it becomes dull. When all the old adhesive is soaked and scraped, spray the window again and clean with a squeegee. Discard any towels used in the cleaning process. You can find detailed instructions for removing both old window film and adhesive at

We bought a house with an old wood shed that smells of mildew. The shed has no windows or vents and probably was closed for years. Should I power-wash the interior with bleach? -- T. Snedden

Power-washing with bleach seems like overkill. If you can see mildew or mold, scrub those areas with a detergent-water solution. Then improve the ventilation inside the shed. Buy a couple of ventilating grilles used in crawl spaces and cut a hole in each side of the shed to fit the grilles.

Screw the grilles to the outside. Also leave the shed door open on fair days when possible. These steps should reduce or eliminate the odor.

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