The RoMac Building Supply Whole House Commodity Index fell 0.5% in October to $54,037, down from $54,318 in September. But lower lumber prices don't tell the whole story. OSB climbed for a second consecutive month, fuel costs surged, mortgage rates reached 7.40%, and tariffs continue to put pressure on building costs. Explore the latest commodity price movements, housing market trends, and what builders should watch heading into the final months of 2026.