Insulation Installation for Quieter, Cheaper-to-Heat Buildings

Hamilton County falls in climate zone 5, which drives the numbers the code official is going to look for. In practical terms that means R-49 or better in the attic, cavity insulation in the R-13 to R-21 range for above-grade walls depending on framing depth and whether continuous exterior insulation is present, R-15 to R-19 in basement and crawlspace walls, and rim joists treated as their own detail.

Numbers on a bag are not the same as performance in a wall. A batt that is compressed around wiring, cut short at the top plate or left with a gap behind an outlet box loses a real share of its rated value. We cut batts to fit around obstructions instead of stuffing them, split around wires, and fill the narrow bays at corners and headers.

Insulation also only performs when the air is stopped. We seal top plates, penetrations, band joists and the gap between framing and masonry before insulating, because a cavity with air moving through it is a cavity that is barely insulated.

Attics give you the fastest return in an older Noblesville house. We air seal the ceiling plane first, seal the top of every interior partition, box out recessed lights that are not rated for contact, then blow to depth with baffles keeping the soffit vents open.

Rim joists are the single most overlooked area in central Indiana homes. That band around the perimeter of the floor system is thin, leaky and directly exposed to outside air. Two to three inches of closed cell foam there fixes a cold first floor better than anything else you can do for the money.

Basement walls need insulation that tolerates moisture. Foam applied directly to the foundation, followed by metal stud framing or wood framing held off the wall, keeps the dew point out of the cavity. That is the sequence we use on basement finishing jobs so the finished space stays dry.