Home Building Diary

DI - During Insulation

October 3rd, 2006

The insulation crew was supposed to arrive Friday morning, but didn’t get here until 12:30. They came all the way from Williamsburg, which is quite a hike, but they didn’t get an early start either. Anyway … they arrived in two big trucks.

The first thing they did was to cover windows, doors, electric recepticles, etc with plastic or tape. This protects them from the spray foam insulation.

Then the real fun started. Polyurethane spray foam insulation was shot onto the walls and ceilings. It’s a closed cell foam that quickly dries hard and sturdy. The foam is a vapor barrier and seals all the cracks and holes in the structure.

An inch of the foam insulation went onto the walls and ceiling. It could be used to fill the entire wall, but this closed-cell stuff is expensive, so they used another product behind it.

Cellulose insulation was used to fill the walls and ceiling behind the foam. Cellulose is relatively inexpensive but still has pretty good thermal insulation properties (3.4 R per inch) and excellent sound absorption properties. Damp cellulose is blown on the walls. Netting was stapled to the roof rafters to hold the cellulose packed up there.

You can see that the blown cellulose makes a terrific mess. While one guy blows it in, another guy shovels up the excess, hauls it back out to the truck, and it gets blown back through the machine for another chance to stick on the wall.

The end result is walls and ceilings packed tight with insulation. The house seems “hushed” now, and it doesn’t cool off much overnight. Brilliant!

The crew also put plastic on the ground in my crawl space to control rising dampness. Plain old fiberglass batt insulation was put under my floor. They also sprayed a non-expanding foam around my windows. They even caulked where the walls meet the floor and where two outside walls meet. It was a very thorough job.

They didn’t finish until 11 pm. A late night for all.

I’m happy with my new insulation. It cost about twice what it would’ve cost me to buy fiberglass batts, but this did a much better job of sealing air infiltration … and I didn’t have to do it myself.

Entry Filed under: construction