Builders got faster last year and it didn’t help them much. The average single-family home took 8.8 months from permit authorization to completion in 2025, down from each of the prior three years, according to NAHB economist Na Zhao’s analysis of the Census Bureau’s 2025 Survey of Construction. The same dataset shows the share of for-sale homes that sold only after they were finished climbed to 31.5%, up from 27.0% a year earlier.
That’s the number to sit with. Cycle time is one of the few inputs a builder actually controls. Demand is not.
Where the 8.8 months goes
The average splits into 1.4 months from permit to start and 7.4 months from start to completion. It’s still roughly 1.6 months longer than the 2015 average, a gap NAHB attributes to a tighter regulatory environment and the skilled labor shortage. Worth flagging that the causal claim is NAHB’s; the Census survey measures duration, not why.
Purpose of construction drives most of the spread. Built-for-sale homes are quickest at 7.4 months. Contractor-built runs 11.7, built-for-rent 12.4, and owner-built 14.3.
Size produces a U-shaped curve that looks strange until you read the composition. Homes under 1,200 square feet took 12.2 months, slower than anything up to 4,000 square feet, because roughly half of them are built-for-rent. From there it climbs: 10.7 months at 4,000 to 4,999 square feet, about 12 months at 5,000 to 5,999, and 16.3 months above 6,000. Small homes aren’t hard to build. Rental portfolios are just slower.
The regional spread is a business-model difference
South Atlantic is fastest at 7.6 months. New England is slowest at 13.5, with Middle Atlantic at 12.6, Pacific at 10.3, and Mountain and East South Central both at 9.1. Permit-to-start ranges from 1.0 month in the East North Central and West North Central divisions to 1.8 months in New England.
A 5.9-month gap between the fastest and slowest divisions isn’t a productivity story. It’s a difference in how many turns a framing crew, a plumbing sub or a truss supplier gets per year, and it flows straight into what they can charge.
What the sales-timing shift actually costs
Among for-sale homes completed in 2025: 31.5% sold after completion, 18.5% sold in the completion month, 29.3% sold under construction (down from 33.0%), and only 12.3% sold before construction started, down from 15.2%. Another 8.3% of completed homes were still unsold when the survey was taken.
Read those two trends together. Builders shaved weeks off the build and then held the finished product longer. On a spec house, every month of standing inventory is interest, taxes, insurance and maintenance against a unit generating nothing. The schedule improvement is real, and the market took it back.
One caveat on all of it: this is 2025 data published in September 2026, describing a year that’s over. Single-family conditions have softened since. Anyone using 8.8 months as a planning assumption for a 2027 start should treat it as a floor, not a forecast. Affordable and mission-driven housing runs on a different clock entirely, as the phased delivery at Westpark in West Philadelphia shows.