Part VI: Insulate and Air Seal your Attic Hatch for Energy Savings

Series: Installing Blown-in InsulationPermalink

Save money by adding blown-in insulation to your attic.

Of the many prerequisite tasks to adding blown-in insulation to an attic, perhaps one of the most important is having an air tight and well insulated hatch to limit air infiltration.

What follows are the steps I took to increase the insulation and ensure a good seal between the unconditioned attic above and the conditioned room below.

A Secure Grip with Pine Boards and Sash Lifts Permalink

I went into my attic so many times in preparation for adding the blown-in insulation. It was important to me to easily and securely grab onto the attic hatch, which is why I added sash lifts to use as handles.

I secured a couple pine boards, cut to size, on each side of the hatch to create a level plane with the entry frame. On top of these boards I screwed in the sash lifts.

The sash lifts made it much easier to maneuver the hatch through the passage, especially once I installed the (very tall) insulation dam.

A Tighter Seal with Sash Locks and weatherstripping Permalink

To guarantee a good seal, I paired sash locks with a gasket of foam weather-stripping around the frame of the attic hatch. When the sash locks are rotated in-use they form an air tight seal with the foam weatherstripping. (My apologies for the lack of photos, but you can surely imagine how it works.)

Glue Layers of Insulation to Hatch Permalink

On the top side of the attic hatch I glued twelve layers of polystyrene insulating panels. Each panel has an R-value of 2.9 for a total R-value of ~35 above the hatch. This is an improvement over the decades old fiberglass batt that was previously nailed onto the hatch.

I’m content with the new R-value, but in hindsight I wish that I had used extruded polystyrene foam (XPS), which is rigid and has a greater R-value. At the time my local big box store wasn’t selling XPS in sheets that I could easily fit into my car.

Take care to use an appropriate construction adhesive to secure the polystyrene. Some glues can actually burn through the panels, so find one that is explicitly designed for expanded polystyrene (EPS).

Also note that I covered the layers polystyrene with a layer of HVAC foil tape to stop the small foam beads from coming off due to occasional friction. I wasn’t always so careful and knocked the hatch into attic rafters a fair number of times.

A Freshly Painted Attic Hatch Permalink

Once I (finally) finished adding the blown-in insulation I painted the bedroom closet that allows entry to the attic. It looks pretty nice, if I say so myself.

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