Why this page has no prices on it
Published modular prices go stale within a season and are wrong by region on the day they are printed. A number attached to a factory in one state tells a reader in another almost nothing, and the parts of the budget that actually vary, land and site work, are the parts no manufacturer can quote.
So this page does not give figures. It gives the structure of the budget and the questions that turn a factory quote into a project number. That is more useful, and unlike a price it does not expire.
What a factory quote covers
A manufacturer quotes what leaves the plant. Typically that means the modules themselves, built to an agreed specification, with interior finishes to a selected level, fixed and sealed for transport, ready for collection or delivery to an agreed point.
Read the specification level carefully, because it is where two quotes stop being comparable. Cabinetry grade, window performance, floor covering, insulation values and whether the mechanical equipment is installed or shipped loose all sit inside the same word, finished, and can differ by a wide margin between two plants quoting the same house.
What it never covers
Everything below is a real cost on a real modular project and none of it is in the factory number. This is not a criticism of manufacturers. It is simply the boundary of what a factory sells.
| Item | Who prices it | Why it varies |
|---|---|---|
| Land | Market | Location, services, entitlement |
| Survey and site assessment | Surveyor, geotechnical engineer | Slope, soil, flood, access |
| Site access work | Site contractor | Whether a truck and crane can reach the setting position |
| Foundation | Site contractor | Soil, frost depth, foundation type, tolerance required for the set |
| Transport and permits | Hauler | Distance, module width, route restrictions, escorts |
| Crane and set crew | Set contractor | Reach and weight, which govern crane size and day rate |
| Marriage line and button-up | Set contractor or builder | Joining, sealing, roof and siding completion at the join |
| Utility connections | Trades and utilities | Distance to services, whether they exist at the boundary |
| Site-completed finishes | Builder | Everything deliberately left off for transport |
| Permits and fees | Jurisdiction | Entirely local |
| General contractor fee | Builder | Scope retained, and who carries the schedule risk |
Note
The table above lists cost categories, not amounts. Any figure you are given for one of these lines is a planning range until it is a written quotation for your specific site, and no page on the internet can give you one honestly.
Cost per square foot is worse here than anywhere else
Per square foot is a poor comparison tool on any house, because it treats a kitchen and a spare bedroom as the same commodity. On a modular project it fails harder, for a specific reason: it invites you to divide the factory price by the floor area and compare that against a full site-built cost per foot, which includes foundation, site work and connections.
The comparison is not close to fair, and it consistently flatters the factory. If you want a per foot number, build it from a complete project budget, including every line in the table above, and compare it against a complete number from the other method. Any other version of the calculation is comparing a component against a building.
The payment schedule is a financing document
Most of a modular budget is spent in a different order to a site-built one, and the order is the part your lender cares about.
A site-built job pays for work that is standing on the security. A modular job pays a factory for a building that is standing somewhere else, often before the foundation exists. That is not a quirk of one manufacturer, it is how the model works: the plant is carrying materials, labour and floor space on your behalf and will not carry them unsecured.
So the payment schedule is not a commercial detail to settle at the end. It is the document that decides whether the project is financeable at all, and it has to be agreed by three parties who are not in the room together: you, the manufacturer and the lender. Get the manufacturer's standard schedule in writing early, take it to the lender before you sign anything, and treat any gap between what the factory requires and what the lender will release as a live risk rather than a formality. It is the most common place these projects stall.
How to make two quotes comparable
Ask each supplier to price the same scope boundary, in writing, and to state explicitly what falls outside it. Then ask five questions that reliably expose the difference.
Which specification level is quoted, item by item, for windows, insulation, cabinetry and mechanical equipment. What is shipped loose rather than installed. Who is responsible for the set, and is that a quoted price or an allowance. What tolerance the foundation must be built to, and who verifies it before the crane arrives. And what the payment schedule is, in dates rather than milestones, because that is the line your lender has to agree to.
A supplier who answers all five plainly is telling you what they actually sell. One who answers in adjectives is quoting a different thing to the one you are comparing it against. The wider budgeting method is on The Build Sheet under planning.
Questions
- Is modular cheaper than site built?
- Sometimes, and never by the margin the factory price implies. The factory price is a component. The comparison that means anything is a complete project budget against a complete project budget, on your own site.
- What is the largest cost most people miss?
- Site work, in the general sense: access, foundation, and utility connections. It is the part no manufacturer can quote, it varies more than anything else in the budget, and it is decided by the land rather than by the house.
Sources
- 1U.S. Census Bureau. Type of Construction Method of New Single-Family Houses Completed, Characteristics of New Housing, 2025 data, released 1 July 2026. Accessed 2026-08-29