Blown fiberglass in West Palm Beach attics.

From a bare deck, R-38 of blown fiberglass is about 15 inches. Most West Palm houses are not bare. Four inches of settled batts is closer to R-9, and the planner adds about 12 more inches of fiberglass to close the gap. That is the published 1,800 square foot example, not a guess from a different city.

Fiberglass is the default east of I-95 and west of it. Summer storms find old tile and old flashing. Cellulose holds that water. Fiberglass drains and dries. If the deck is already wet, we do not blow either material until it is a removal.

Low attics are the exception. A 1920s house in El Cid or Old Northwood sometimes cannot take 15 inches without burying the ties. That is when we switch to cellulose and say so before the truck is loaded.

The rest of the job is the same either way. Baffles at the soffit, air seal at the top plates, dams at flues and bath fans, a marked depth, and a weatherstripped hatch. The install, step by step.