Attic Stair Cover

Background

To better insulate my house, I've used an insulation tent over my attic stairs. You can buy that at big box stores or Amazon.com. I've gone through two of these and the main issue is their flexibility. Over time, they start to lose their shape, then they start getting hung up in the attic stair hinges, then they start to tear. Their flexibility also means it is tricky to put on since adjusting one end can mean the other end does something unwanted.

This time I tried to some something different after seeing a number of YouTube videos for making something rigid out of foam board. There are many videos out there, so I'll not give detailed instructions here, just an overview.

Cutting Foam Board

You start with a 1 in. foam board that you can easily cut with a utility knife. Measure your opening then cut the top and four sides. What you really need to measure is the place you want this the cover to sit on, which is going to be a bit larger than the opening itself.

Cut top of attic stair cover

Scrap remainder foam board

Note that this comes in a 4 ft X 8 ft piece that did not fit in my car. I brought a utility knife with me to Home Depot, along with the knowledge of where to cut. I cut this in the parking lot after purchase so it would fit in my back seat.

Tape Outer Edges

You also need some 2 in. aluminum (metal) tape. First tape the outer edges only to make the box shape.

Tapes sides to cover

Tapes sides to cover (alt)

All sides taped to top

Sealant on Inner Edges

They sell special sealant/adhesive for these foam boards, so I applied that to the inner seam.

Sealant applied (corner)

Seam sealant closeup

It is not clear you need this sealant. The tape alone might be enough to hold it and seal the seam.

Tape Inner Edges

I then also applied the aluminum tape to the inner edges because if there's a chance to over-engineer for structural strength, I'm likely going to do it.

Tape over sealant for inner edges

Tape Bottom Surface

After cutting with a utility knife, the ends that will actually sit in the attic floor can be ragged. I taped over them to both smooth it out and also to seal it from moisture getting into the foam.

Tape on bottom edges

Bottom Weather Stripping

My attic floor is neither flat nor smooth, so just laying this cover over it leaves some small gaps. I attempted to solve this by putting weather stripping along the bottom edge. This did not work. The cover is too light so it does not exert enough downward force to compress the weather stripping. I would need something much, much soften in order for this to work. I decided to just live with the gaps for now.

Weather stripping (did not work)