Every modular factory tour starts the same way. Here is the square footage. Here are the lines. Here is the [insert impressive machine here]. It all looks great, and it tells a developer or an investor almost nothing about whether their project will get built on time.
It is the This Is Spinal Tap sales pitch. Nigel's amp is better because "these go to eleven." Square footage is the eleven on the dial. It looks impressive and tells you nothing about how loud the plant actually plays.
Square feet is not capacity. Reliable capacity is proven, sustained output at a known product mix, with the people, materials and engineering in place to hold it week after week. A big building with two shifts of open positions and a design backlog has less capacity than a smaller plant running steady.
Questions to ask about modular factory capacity
If I am sitting on the buyer's side of the table, these are the questions I want answered. What is your proven output per week over the last two years, not your best week? At what product mix? Where is the constraint in the plant today? How much of your capacity is already booked for the next twelve to eighteen months? What was your average utilization last year?
That last question is the one nobody likes. It is also the one that tells you the most, because it shows how much of a factory's capacity the market is actually consuming.
How much offsite capacity is the market using?
The national numbers are sobering. In October, an analysis of Census data by the National Association of Home Builders showed that about 30,000 of the 975,000 single family homes completed in 2025 were modular or panelized. That is roughly 3%, the same share as the year before. On the multifamily side, about 3% of buildings were modular or panelized.
Meanwhile the need has not gone anywhere. In September, the Bureau of Labor Statistics updated its construction productivity measures and reported that labor productivity fell 4.5% in single family construction and 7.4% in multifamily construction in 2025. If there was ever a market that needs a better way to build, this is it.
So is there enough demand for offsite? The housing numbers say yes. Is there enough reliable capacity that buyers trust? Not yet.
There is an old racing saying: to finish first, you first have to finish. Capacity that cannot hold a delivery date is a car that never sees the checkered flag.
Why reliable capacity is the missing piece to mass adoption
Capacity and demand are stuck in a loop. Developers will not design a pipeline around offsite until they trust that capacity will be there when they need it. Factories cannot hold trained crews and steady material flow without a steady pipeline. Underused capacity is expensive, because fixed costs get spread over fewer units, which pushes price up and makes offsite harder to choose. Overbooked capacity is just as damaging, because it turns into delays and broken promises.
Both ends of that loop erode trust, and trust is what the industry is short on. It is the same theme I wrote about back in February, on why offsite construction adoption is so slow.
What would break the loop
Report capacity honestly, in units per week at a defined mix, alongside how much of it is booked. Plan capacity regionally, so a project is not betting on a single plant. Standardize the interfaces between design and production so that work can move between factories when one is full. That starts with treating the delivery system as the product. And on the demand side, commit programs, not one off projects, so factories can plan around volume instead of hoping for it.
None of that is as photogenic as [your most impressive machine], but it is what an industry is built on.
Big factories make good photos. Booked, reliable capacity makes an industry.