Need help to build an attic stairway cover

[Louis Brandt]

Hello,
This isn’t really a woodworking question, but it is a question about building something out of wood. To achieve better insulation, I need to build a “box” to sit upside down in my attic over the stairway opening in the attic, since this area must be opened to service the heating unit in my attic and therefore, isn’t insulated. I’ve seen one manufacturer selling something like this on the web, but that one is built from heavy corrugated cardboard and covered with fire-resistant material. The box would be something on the order of 30 inches by 60 inches by 8 inches deep.
I was thinking of building it from either MDF or plywood, and I’d probably either line it with batt insulation or put batt insulation on top of it.
I’m wondering whether any of you have built anything similar for your attic. Would either MDF or plywood present a fire hazard? I would think not, since my entire attic is built of wood, but I’d still like opinions as to which material would be best to use for such a project. And would MDF be able to handle the high and low temperatures that it would find in the attic? I live in the South.
Any ideas would be appreciated.
Thanks,
Louis

[Todd Hyman]

I built one myself from 1/2" pine boards for the sides and 1/2" plywood for the top. Put R-30 bat insulation in and stappled it to the sides. Caulked all joints, installed rubber weatherstripping on to the bottom (where it rests onto the attic joists).

Some things to think about is to make the box big enough so that it rests on the joist opening and tall enough as the stairs+insulation have to go up into the attic. Mine's pretty heavy but it works good and I feel no cold air. Also add some handles on at least two areas on the inside of the box to help you lift it as your walking up the ladder. I know that HD in Nashville area carries an insulated cover that is made from foam iso board and its very lite but it cost about $80 I think.

[Ben Grunow]

You have the idea except I would use a couple layers of rigid foam as it will stand up over time a little better.

I would also include a way to hold it open so it does not slam down on your head when you are making the 5th trip with the christmas ornaments. DAMHIKT.

Ben

[Victor Stearns]

I built my cover from 3/8" ply and some 2x2 stock. I added rigid foam board to the inside and sealed the corners with caulk. I attached one end to the rafters with strap hinges. The box is sized slightly narrower than the spacing between the trusses. It rests on the frame for the stairway. So now I open the stairway and push the cover over. As the strap hinges are not heavy duty they flex enough that the cover just kinda leans back out of the way.
Hope this helps.
Victor

[richard poitras]

Owens Corning (pink insulation company) sells an attic cover like you want it is all foam and just sits on top; very easy to install and remove they have them on their web site ..

[Thomas Canfield]

A 4' x 8' sheet of 3/4" rigid foam insulating board should provide enough material to make a frame and add some stiffeners for the span. Foil back duct tape makes tight joints and several layers provides additional protection from tearing, and a utility knife with a straight edge puts you in business. The whole thing could then be positioned/moved from below since weight would be less than 10# unless one goes completely wild with duct tape. You could even stick some additional roll insul to attic side to have more insulation and still not have a heavy frame like wood.

Not woodworking, but I have used the foam as prototype material for projects to checkout sizes, etc.

[Rob Will]

I just made an attic door for my shop with a pine frame, 1/2" plywood and layers of foam board. Felt weatherstripping stapled to the bottom side provides a seal.

Rob

[Ted Jay]

Owens Corning (pink insulation company) sells an attic cover like you want it is all foam and just sits on top; very easy to install and remove they have them on their web site ..

Richard is right. It's a big pink 4 inch thick foam insert you place at the top of the stair opening. About $80 at the depot last I saw.
http://www.owenscorning.com/around/insulation/products/pinkcap.asp (http://www.owenscorning.com/around/insulation/products/pinkcap.asp):)