How to insulate an attic access cover

Dear Jim: I just had a house built and discovered no insulation on the attic opening cover. Shouldn’t the cover be insulated and sealed? If I add folding stairs, how can I insulate them? — Mike M.

Dear Mike: Builders don’t always insulate and seal the attic access opening cover, but it certainly should be added for energy savings. Most often, just a scrap piece of plywood or drywall is cut somewhat close to the correct size and placed in the opening, resting on a strip of molding. That type of cover’s insulation value is less than R-1 and leaks air like a sieve.

Because the attic access is often in the ceiling of a bedroom closet or hallway, the air leakage and heat loss/gain are seldom noticeable.

During summer, attic temperatures can get extremely high, and the air is humid, so you don’t want it in your living space. During winter, the heated air in the house, because it is less dense, tends to leak up and out.

The simplest fix is to attach insulation to the top of the cover and weather stripping underneath where it rests on the lip of the opening. Measure the cover to make sure it fits the opening, with the cover overlapping the molding lip so the weather stripping seals well. If you have to make a new one, a piece of ½-inch drywall works well and is fire-resistant.

The insulation on the top of the cover should be up to the recommended ceiling R-value for your area — visit www.ornl.gov/~roofs/Zip/ZipHome.html to learn the appropriate level for your home. (Adding more insulation above this level will not help appreciably.) In a well-insulated house, even just several square feet of uninsulated floor can lose a considerable amount of heat.

Before you add weather stripping to the molding lip, place the cover over it and check whether it’s even. The lip often consists of pieces nailed to the sides of the opening and isn’t level. You may have to pry a side or two loose and reattach it. If it’s very uneven, it will be difficult to get a good seal under the cover no matter how compliant the weather stripping is.

The next step is to attach adhesive-backed foam weather stripping to the top edge of the lip around the opening. Use as thick a foam as you can find to accommodate any out-of-level edges. The weight of the plywood and drywall should be adequate to compress the foam weather stripping.

If you plan to go up into your attic often and want to install pull-down stairs or a ladder or if your attic currently has one, buy a special insulated cover for the attic access opening. You could attempt to make one yourself, but its weight may be hazardous to open and manage when you are on the stairs.

One of the least-expensive options is basically a three-sided, heavy-duty cardboard box. It’s easy to open and assemble, and then you can attach your own insulation to the top and sides. It’s very lightweight and easy to lift and handle when you enter the attic on the stairs.

An efficient option is a lightweight, rigid-foam-domed device that covers the folded stairs or ladder from above. It’s strong, and the foam provides adequate insulation. Another design uses a flexible, zippered insulated cover that is permanently attached to the attic floor for a good, airtight seal. The zipper provides a large opening for easy access to the attic.

TogetherWeSave.com, an energy-efficiency website from the nation’s electric cooperatives, has two videos on this subject as part of its “Watch & Learn” series; visit energysavings.togetherwesave.com/watch-and-learn and click on the “Sealing & Insulation” tab. Then scroll down to find how-to videos on insulating attic hatches and pull-down stairs.

These companies offer attic entrance products: Atticap, 781-259-9099, www.draftcap.com; Attic Tent, 877-660-5640, www.attictent.com; Battic Door, 508-320-9082, www.batticdoor.com; Calvert Stairs, 410-286-1430, www.calvertusa.com; and Rainbow Attic Stairs, 877-369-6996, www.rainbowatticstair.com.

Have a question for Jim?

Send inquiries to James Dulley, The Tennessee Magazine, 6906 Royalgreen Drive, Cincinnati, OH 45244, or visit www.dulley.com.