Most attic hatches and pull down stairs have major air and heat leaks.

Insulating and sealing the attic hatch or stair is an essential step to gaining a more comfortable and energy efficient home.

Attic hatch insulation

• Most attic hatches can be insulated with three two-inch layers cut from a single 4' X 8' sheet of high-density polyisocyanurate or Polyurethane foam board insulation. The middle layer may have to be assembled from smaller pieces.
• These high R-Value foam board insulation products are lightweight, rigid, and about R-8 per inch. Six inches will give you a very energy efficient R-48.
• The top layer of insulation will be larger so it can extend out a few inches on all sides to lap over the frame box around the attic hatch. Measure carefully and trim the top layer of insulation so it just fits over the hatch frame.
• An additional layer of foam board can be added if more height is needed to lap over the hatch cover framing box.
• Glue the pieces of insulation to the attic hatch cover with construction glue that is rated for foam board. Use an evenly distributed weight sufficient to hold the pieces tight until the glue sets.
• Eliminate all air leaks around the edges of the attic hatch with two thick and wide bands of self-adhesive low-density foam weather stripping.
• Seal the joint between underside of the overlapping foam board insulation and the top surface of the box frame around the hatch. Use more than one course of the foam weather stripping to make the band of foam as wide as the space will allow.
• As a second air leak barrier, also apply the same weather stripping to the top of the trim molding that covers the edge between the hatch cover and the ceiling. Again, make the band as wide as the space will allow.
• The weight of the insulated hatch cover will compress both bands of the foam weather stripping and provide an airtight seal. You will have gained much improved personal comfort and home energy conservation.

Insulating fold down attic stairs

• Fold down attic stairs are very convenient. And they are a major source of air leaks and heat loss that compromise the energy conservation of your home.
• Two solutions are available. Buy and assemble a kit. Or build an attic stair insulating box on your own.
• Thermadome makes a kit that works well, is reasonably priced, and is relatively simple to assemble and install. It comes with everything you will need including weather stripping, glue, metal foil tape, etc. It even has Velcro strips to hold it securely when in place.
• To build an insulating box for your attic stairs you will need a two inch thick 4'X8' sheet of either High-density polyisocyanurate or Polyurethane foam board insulation with at least one reflective side.
• Measure carefully to be certain that the top of the box will be high enough to clear the fully retracted stairs. The box will need to sit on the attic floor or the framing around the attic stair well.
• Use a framing square to get straight corners. After re-checking the marked measurements and confirming that each piece is truly square, make several passes with a utility knife to complete each cut. Use a metal straight edge to guide the blade.
• Face the reflective side of the insulating foam board inward. Use nails pressed into joints to test fit the pieces and to hold them together during gluing.
• Use construction adhesive rated for foam board and clamp until set. Reinforce all four corners with glued in triangles cut from left over foam board. Use metal tape to seal the inside and outside of all the seams and add strength.
• To eliminate air leaks when the cover is in place simply attach a wide band of thick low-density self-adhesive foam weather stripping around the bottom of the attic cover.
• Add a second broad band of the foam weather stripping to the stair cover where it presses against the bottom of the stair frame box.
• The stair cover can simply be pushed aside on a smooth attic floor. Otherwise, three large hinges can be attached to one side of the cover using fender washers to keep the small bolts from pulling through the foam board. Wood screws will anchor the hinges to the attic structure.

Summary

• You now have an air tight R-16 attic stair well cover that will greatly improve the total energy efficiency and comfort of your home!
• This is a great first medium sized energy conservation project.