Thursday, December 30, 2010

An attic access insulation baffle

Pull-down attic ladders typically have very little insulation, mine only has a single thickness of rigid polystyrene, while the rest of the attic is insulated to R50. This allows a large amount of heat gain in the summer and heat loss in the winter, which represents wasted money.

So I decided to make a insulated box for the door which is lightweight and movable. The box is made from two layers of foil-faced polyisocyanurate board. This has the highest R-value of any common insulation you can buy, typically R-7 or R-8 per inch.

I purchased one sheet and was able to make this box, which measures 23 x 55 x 9 inches. The board cuts easily with a box cutter and I taped it together with aluminum HVAC tape - not to be confused with duct tape, which is worthless for basically every task I have ever used it for.

Here is my attic hatch open. I built a box of 2x8's around the opening last year, which is strong enough to stand on.

The baffle installed. It fits well, although i will probably make a gasket of plastic sheet around the rim to get it airtight. For now this should lower my heating bill.

Took about an hour in all! Not half bad for $20 in materials.


benthomasson said...

So, can I just add another layer of insulation on top of the existing insulation in the attic?

Glenn Hackleman said...

yeah. Just make sure you don't create a vapor barrier. If your insulation has a facing, remove it.