[TimJFowler]

The original attic insulation (still in place) is old mineral wool (rock wool) blankets. Unfortunately, they were installed sloppily and had settled to 2-3 inches thick (I assume they were thicker initially). Whomever installed the insulation left gaps between batts, ran batts OVER wiring, and ran batts flush against the eave vents. I had to get creative to position some of the insulation trays up to the eave vents.

The biggest problem was the big thermal break created by the central hallway. The hot air supply duct runs down the central hallway in a channel created by dropping the hall ceiling about 6". This left the interior of both hall walls open to the attic and the duct itself was uninsulated. I sealed over the top with sheets of drywall cut to fit and then sealed in place with spray foam.

Doing all of the prep work in the attic was a big pain in the rear, but I noticed a difference in how often the furnace was running even before the insulation was blown in.

This was definitely a big project time-wise, but absolutely worth it.

Tim