The next ROCKWOOL price increase is out: 6% on 14 stone wool building insulation lines for U.S. customers, effective Jan. 1, 2027. It lands six months after an 8% increase on most of the same products, so a contractor who priced Cavityrock or Curtainrock last spring is looking at a list price about 14.5% higher by New Year’s Day.
The customer letter, dated Oct. 1 and signed by Brian LeVoguer, vice president of building insulation at ROCKWOOL North America, gives no reason for the move.
What the ROCKWOOL price increase covers
Every line gets the same 6%: AFB, AFB evo, Cavityrock, Comfortbatt, Comfortboard, Curtainrock, Fabrock, Frontrock, Plus MB, Rockboard, ROXUL Safe, Safe ‘n’ Sound, Smartrock and Toprock. That’s the rainscreen and curtain wall boards, the safing and acoustic batts, the roof board and the residential batts in one sweep. Fabrock and Smartrock weren’t on the July list.
The term that matters is the ship date. The increase applies to anything shipped on or after Jan. 1 “regardless of the date of order placement,” the letter says.
That clause has teeth right now. General Insulation Company, the distributor that posted the letter on Sept. 30, is running a banner on its website that puts ROCKWOOL lead times at 66 days. Count back 66 days from Jan. 1 and you land on Oct. 27. If that lead time holds, an order placed after the last week of October ships at 2027 pricing whether or not the buyer planned for it. Lead times differ by product and plant, so get yours in writing.
Two stone wool insulation increases in six months
ROCKWOOL announced the earlier 8% on April 1 for July 1 shipments, covering 12 lines. Its technical insulation unit raised industrial pipe and marine products 8% on the same date, and that letter did give a reason: inflation in energy, raw materials and logistics. Melting rock is energy-hungry work, and diesel at $6.45 a gallon doesn’t help a product that ships as bulky, light freight.
The parent company isn’t short of demand. ROCKWOOL’s Aug. 19 half-year report showed second-quarter revenue of 1 billion euros, up 10%, and raised full-year growth guidance to a range of 5% to 7%. The same report showed EBIT margin slipping 0.9 points to 12.9% on higher energy and transport costs, and said the U.S. business had done especially well. Strong volume and a squeezed margin is the textbook setup for a price letter.
What it means for bids and buyout
List increases aren’t always what the market pays, and distributors negotiate. But mineral wool is hard to swap out where it’s doing fire duty. Perimeter fire containment and safing details are tested as assemblies, and substituting another insulation means a different listing or an engineering judgment. On those scopes, expect most of the increase to stick.
It’s not the only letter in the pile. The same distributor’s price notice page lists a 9% increase on steel products from CL Ward and 8% from ZM Sheet Metal, both effective Nov. 1, plus 1.5% from H.B. Fuller on Oct. 12. That squares with the 1.28% quarterly rise in RLB’s cost index, the fastest in two years.
Estimators carrying insulation or firestopping scopes into 2027 should reprice now. Anyone holding a first-quarter delivery on a 2026 quote should ask the supplier one question: which price is on the invoice if the truck leaves Jan. 2?