How To Build Attic Stair Cover | Big Energy Savings
Written by Todd Fratzel.
Attic Stair Cover
If you have an attic access hatch or a set of pull down attic stairs chances are good that you also have a tremendous amount of heat loss through that opening. We all know that heat rises and we all know that any opening to the outside will allow warm air to escape and cold air to enter our homes. Most people never think to check that old dusty attic access to see if it is properly insulated. In fact, most access hatches are located in a closet or out of site so we naturally forget about them.
Typically there are two types of hatches. One would be some type of plat panel door resting on top of trim or moulding. To access the attic you push the plat panel up into the attic. Therefore this type of panel rests on top of the moulding. The second most common type is a set of pull/fold down stairs. The “door” for this type of access is spring loaded and closes from the finished side up against the trim of the stairs.
Fall is a great time to install an attic stair cover. Building your own attic stair cover is really easy to do and costs about half what a store bought version will cost.
Standard Attic Stair Covers
There are certainly lots of different attic stair covers on the market if you want to buy one. Standard attic stair covers will work on most any attic stair unless you have a unique situation like our house. If you’re interested in buying an attic stair cover then check out the following link:
I think the manufactures of these attic stair covers are a bit misleading. Although the product claims and R50 insulating value I find that hard to believe when you see that the sides are not insulated. However, the standard attic stair covers are quick and easy to install.
DIY Attic Stair Cover
Because I want an attic stair cover that is insulated on all four sides I needed to come up with a unique design. As you can see from the adjacent photo our attic stair is adjacent to the edge of the vertical truss members. This creates a challenge because I cannot install the attic stair cover on top of the plywood sub-floor all around four sides.
So I decided to build my attic stair cover in two pieces, one piece is somewhat permanent and the other is removable. The first piece of the attic stair cover is installed between the truss members while the second piece installs over the plywood sub-floor and overlaps the first piece.
DIY Attic Stair Cover Materials
To build the attic stair cover I decided to use two inch thick foil faced foam board by DOW – TUFF-R. The TUFF-R has an R value of 13 (for 2 inches) and a foil facing which works great as a radiant heat barrier as well. The foil faced insulation board is also really easy to connect to other pieces using foil tape. The insulation is also really easy to cut with a table saw or utility knife.
Insulate / Seal Opening First
Before I began working on the attic stair cover I wanted to be sure the attic stair frame was properly sealed and insulated. Attic stairs are installed in a rough openening, shimmed and fastened in place. The shims leave a large void that should be sealed. I like to use Great Stuff Foam insulation in a can to seal voids like this.
First I installed a custom piece of attic stair cover. Because of our truss geometry I needed to create a smaller insulated box between the trusses and just past them by a couple inches. I built a three sided box, taped all the corners and then foamed it (Great Stuff Spray Foam) into the opening as you can see in the adjacent photo.
Insulated Attic Stair Cover Box
Finally I made the main insulated attic stair box cover. I made the box wider than the custom piece so it would fit over the first box. I also made the box wider and longer than the attic stair opening so that I could install weather stripping on the bottom to create a tight seal.
I built the box by taping together the pieces. The foil tape sticks VERY well to the foil faced insulation which creates a very strong box. I also installed 1/2 inch thick self-adhering weather stripping to the bottom edge and along the sides that overlap the custom piece.
Connecting Attic Stair Cover
Finally I came up with a connection detail to hold the attic stair cover in place and also create a tight seal. I installed four bolts in the corners of the box. I used 3 inch long carriage bolts with large fender washers. The carriage bolts are nice because they stand off the fender washer as you can see in the photo.
Next I bought some 3 inch long springs. I connected the springs to the carriage bolt on the box and a screw that I installed on the attic stair frame. As you can see I was able to put a good amount of tension on the springs which applies pressure to the attic stair cover which creates a good seal.
Attic Stair Cover Cost
The whole project cost about $30 for materials and took about 2 hours to complete. Even though the store bought attic stair covers boast an R value of 50 I doubt that’s the case based on the lack of side insulation. At least my DIY attic stair cover has insulation on all four sides and a nice tight seal.
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