Two materials that go up on the same wall are moving in opposite directions. Drywall prices have been sliding for half a year, down about 11% from last summer’s peak. Fiberglass insulation has done the reverse, climbing roughly 19% over the past twelve months to around $0.64 a square foot. For anyone bidding interior work, that split is a headache.
Why the two diverge
Drywall’s slide tracks softer demand. With commercial starts weak and multifamily uneven, board is moving slower, and manufacturers have room to compete on price even as they mail out increase notices from names like National Gypsum, American Gypsum, and CertainTeed. Insulation is a different story. Fiberglass has posted double-digit year-over-year gains for three straight quarters, driven by energy-code requirements that keep raising the amount of insulation a building needs and by input costs that haven’t come down.
The supply risk hiding underneath
There’s a structural wrinkle worth watching: synthetic gypsum, a byproduct of coal-fired power plants, is getting scarce as those plants retire. Gypsum board leans on it, and its disappearance is exactly the kind of slow-moving supply squeeze that doesn’t show up in a monthly index until it’s already a problem.
The practical takeaway for estimators is simple. Interior finishes can’t be treated as one blended line item anymore. Drywall may pad your margin this quarter while insulation quietly eats it, and locking insulation pricing early is now the smarter hedge. That discipline matters most on residential jobs with heavy interior scope, the kind stacking up at towers like 14 ROC Miami, where hundreds of identical units multiply every per-square-foot swing.