How to Insulate an Attic Door
Sometimes, it isn't necessary to insulate an attic door, because it is located in an unconditioned area of your home, like the garage. Your attic door is more likely in a hallway or inside a closet, though. In that case, it should be insulated with the correct R-value for your climate per recommendations given by the Department of Energy. Insulating your attic door properly will make your home more comfortable and reduce your energy bills.
A knee-wall attic door is infamous for being leaky and all too often left without insulation. An attic hatch, also known as a scuttle hole, is simply a panel in the ceiling that can be removed for access. Despite both of these attic doors being easy to insulate, many contractors don't do it. Fortunately, there are kits available to insulate these kind of doors. Here's how to do it yourself.
Step 1—Apply Weather Stripping
Apply weather stripping to the perimeter of opening, not the attic-door cover. This ensures a tight seal between the door and the opening. In the case of a knee-wall door, insulate the walls. Weather stripping is easy to apply because it is self-adhesive. The most important thing is to press firmly and make sure the opening is clean and dry before attempting to apply it.
Step 2—Measuring the Opening
Measure the width and height of the knee-wall door, or hatch. It is important to get these measurements right. If you don’t, it will make it difficult to replace the attic door once it has been insulated.
With a utility knife, cut out two sections of rigid foam board to the appropriate size. They should be 1/4 inch smaller than the attic door cover. This will make opening and closing the attic door much easier. Glue the two sections of foam board together, and then onto the inside of the attic door. Use foam glue, because many other adhesives will actually destroy the foam. Not a pretty sight!
Step 4—Attach the Fiberglass Batt
Cut the fiberglass insulation to size and glue it onto the top of the foam board, pressing down firmly. Wear gloves when handling the fiberglass batt. Then, let it dry completely. This may take a few hours.
Step 5—Replace the Attic Door
For a knee wall, a latch is essential to make sure the door is snug against the weather stripping. It is the only way to achieve an airtight seal. If the door does not have one, attach one. A latch also makes closing the door easier. If you have a large attic hatch, attaching handles to the door will make it easier to pull down and put back up.