Will an A-frame, a steel kit or a shipping container make your house cheaper to build?
Published
Summary
Probably not by much. In NAHB's 2024 survey, framing, exterior wall finish and roofing together made up about 26% of the average construction cost, while plumbing, electrical, HVAC and interior finishes made up 43%. A container or a steel shell changes the first group. The second group comes with any house you intend to live in.
Where the structure shows up in a budget
NAHB's average house in 2024 had 2,647 square feet of finished space and cost $428,215 to build. The rows a different structural system would touch are these:
- framing, including roof framing, trusses, sheathing and structural steel: $70,982 (16.6%)
- exterior wall finish: $24,450 (5.7%)
- roofing: $16,732 (3.9%)
- the foundation stage as a whole: $44,748 (10.5%), of which excavation, concrete, retaining walls and backfill are $43,002
The first three add up to $112,164, or 26.2% of construction cost. With foundations it's 36.6%. Brick versus siding is a question inside the exterior wall finish line, which NAHB doesn't split by material. Windows and doors sit on a separate line at $15,990.
The part that doesn't care what holds up the roof
Rough-ins for plumbing, electrical and HVAC came to $82,319. Interior finishes (insulation, drywall, trim, paint, lighting, cabinets and countertops, appliances, flooring and plumbing fixtures) came to $103,391. Those two stages alone are $185,710, before site work at 7.6% and final steps like landscaping and the driveway at 6.5%.
So when a container or a metal building kit looks cheap, the question is which of the four rows above that price replaces. Even if it replaced all four, the $185,710 would still be there. The barndominium guide walks through the gap between a kit price and a finished house in more detail.
Framing is already a shrinking share
Say some other system cut framing costs by a third. That saves about $23,660, or 5.5% of the $428,215 total, a bit more than NAHB's average for cabinets and countertops ($19,056).
Framing's share has also been falling on its own. NAHB reports it dropped from 20.5% of construction cost in 2022 to 16.6% in 2024, the lowest since the association started tracking it in 2013. Wood still dominates among people who build for themselves: the Census Bureau found 96% of owner-built single-family homes completed in 2025 had wood framing and 2% had concrete.