Material Costs Climb Broadly in July as Tariffs Keep Biting
RoMac’s Whole House Commodity Index just posted its second straight monthly increase — and this time, almost nothing was spared.
Builders hoping tariff pressure on materials would ease heading into fall got the opposite news this month. RoMac Building Supply’s Whole House Commodity Index rose 1.8% in July 2026 to $55,287, up from $54,288 in June — the index’s second consecutive monthly increase and its highest level so far this year.
What makes July different from June is the breadth of the increase. In June, price gains were concentrated in a handful of manufactured products. In July, increases hit structural lumber, engineered wood products, roofing materials, steel, and interior finish products all at once. RoMac’s analysts were careful to note the causes vary by category: lumber is climbing because of tariffs, mill closures, and shifting log export patterns rather than a genuine demand surge, while steel is responding to domestic tariff policy and tighter mill capacity, and manufactured products are absorbing higher petroleum and freight costs.
Structural lumber led the month. Southern Pine 2×12 rose 10.7%, Southern Pine 2×6 climbed 7.5%, and standard Southern Pine framing lumber was up more than 5%. Spruce studs advanced nearly 6%. Canadian softwood imports — which supply roughly 85% of U.S. softwood lumber — still carry a combined tariff burden of 35.9%, a number that includes the Section 232 tariff that remains in place even after recent adjustments to antidumping and countervailing duty rates. Those preliminary rates actually fell this month (the antidumping rate from 20.6% to 10.7%, the countervailing rate from 14.6% to 14.2%), trimming about 10 percentage points off last year’s combined rate — but the relief hasn’t shown up in prices yet, and it isn’t final.
On the metals side, the picture is even steeper: as of April 2026, steel, aluminum, and copper products made mostly from those metals carry a 50% tariff, with derivative products at 25% and industrial/electrical equipment like transformers, panel boards, and conduit systems facing a 15% tariff. Softwood lumber itself carries a 10% tariff, with lumber derivatives at 25%, on top of a global 10% baseline tariff currently in effect through July.
For Oregon and Washington contractors bidding work into Q4, the practical advice from industry analysts is consistent: build longer-term agreements with steel fabricators and electrical suppliers, use quarterly-reset or indexed pricing mechanisms where possible, and keep at least two qualified suppliers lined up for critical scopes. With the Commerce Department due to report on potential tariff expansion to hardwoods or pallets by October 1, this isn’t a one-time cost bump — it’s a supply chain condition contractors should expect to keep managing through the rest of the year.
Sources: RoMac Building Supply, National Association of Home Builders (NAHB), Gordian, ABC Carolinas
Read more: https://www.romacfl.com/post/romac-whole-house-commodity-index-july-2026
