How should I install a radiant barrier in my attic?
The most effective way to install a radiant barrier in an existing attic is simply to staple the foil material to the underside of the top chord of the roof trusses or to the underside of the roof decking.
It is not very easy to work in any attic, even one with a steep pitch. Always keep in mind that a misstep could be disastrous, since most attic "floors" are not floors at all, but rather 2x4s holding ceiling drywall topped by conventional insulation. You should consider safety first (see installation safety tips listed below).
Take care to avoid compressing existing insulation in the attic.
Tools and materials needed to install a radiant barrier include the following:
• Enough radiant barrier material to cover the underside of the roof
• Measuring tape and flashlight
• Heavy-duty scissors or utility knife
• Staple guns and heavy-duty staples
• Two movable support surfaces such as 3x2-foot sheets of one-inch plywood or three-foot lengths of 1x12 board.
Perhaps your most important aid will be a partner. Working in pairs in the attic makes the work go faster. Even more important, it adds to safety.
Begin by measuring the length of the attic roof from peak to soffit. Then, return to a stable, ground-or floor-level surface to measure and cut the radiant barrier material to size. The material usually comes in rolls of 50 to several hundred feet; it's easiest to cut and reroll all the lengths you'll need before returning to the attic.
At one end of the attic, place the plywood or 1x12 as a stable surface across two of the attic truss members. Try to minimize compression of existing insulation. Provide one surface at the peak and one at the soffit end so that both installers can work together.
Safety reminder: Be extremely careful at the sides of your support surface. If you step on an edge, the surface can tilt and drop you through the ceiling drywall below.
With your partner, unroll one length of the radiant barrier material from soffit to peak. Leaving one or two inches of free space at the roof peak, staple one corner of the material to the underside of the top chord of the first roof truss. Continue stapling the edge of the radiant barrier material down the truss at 6 to 12-inch intervals, stopping 2 to 3 inches from the ceiling insulation. Next, staple the other edge of the material to the underside of the adjacent roof truss. Continue the process at adjoining trusses until the underside of the roof is no longer visible except for a one- or two-inch strip at the roof peak.
As an alternative, you may staple the radiant barrier material to the underside of the roof decking, adjacent to the top chord of the truss. The weight of the material will allow it to drape naturally between trusses.
Safety tips for installing an attic radiant barrier system
• If you use a ladder for access to the attic, make sure it is stable and tall enough for easy entry and exit.
• Work in the attic only when temperatures are reasonable. Attic daytime temperatures can rise far above 1000F during much of the year in the Sunbelt. Install your radiant barrier system early in the morning, or wait until cool weather sets in.
• Work with a partner. Not only does it make the job go faster, it also means that you'll have aid should a problem occur.
• Watch where you walk and use a movable support surface. Step only on the attic trusses or rafters and your working surface. Never step on the attic insulation or the ceiling drywall below it.
• Step and stand only on the center of your movable working surface. Don't step on the edge; it can cause the surface to tip.
• Watch your head. In most attics, roofing nails penetrate through the underside of the roof. If you bump your head, it can cause a serious cut or puncture. If your skin is punctured by a nail, an up-to-date tetanus vaccination is a must. Avoid potential problems by wearing a hard hat.
• Be especially careful around electrical wiring, particularly around junction boxes and older wiring. Never staple through or over electrical wiring.
• Make sure that the attic space is well ventilated and well lighted. Bring in fans and extra work lights if necessary.
• If your attic has blown-in insulation, direct fans upward, away from the insulation material.
• Avoid exposure to mineral fiber insulation. Wear goggles, long pants, a long-sleeved shirt, and a particle mask or kerchief over your nose and mouth. Wear gloves if you are particularly sensitive to fiberglass.
• Wear a tool belt or utility apron to carry staples, staple gun, scissors, measuring tape, etc.
• Take frequent breaks, and pace yourself. It's better to get the job done over a longer period than to risk an accident due to fatigue or to end up with a poor-quality installation.
