Choose the shipping state
A closed module, a flat pack or a folded body determines permits for the road and the crane lift plan on site.
Offsite method trade-offs
ForgeSpan Sourcing offsite methods for modular alternatives
Volumetric modular construction finishes more work before the truck leaves. Panelized construction often packs tighter and shifts more labor to the pad. A foldable unit changes the transport envelope again. ForgeSpan Sourcing writes those differences into the brief so a creative modular construction search does not collapse four methods into one price.
This page compares methods. It does not claim ForgeSpan Sourcing manufactures modules or holds an accreditation such as IAS AC472 or ISO 9001.
Decision points along one purchase
Choose the finish level
Interior finishes completed off site reduce weather exposure and raise the weight that must be lifted.
Choose the frame logic
A rigid frame with purlin and girt spacing is a different package from a cold-formed room module. Do not rename one as the other to force a price match.
Choose the open questions
Thermal transmittance, fire-resistance rating and the foundation interface stay open until a supplier document names the assembly.
What to ask, grouped by method
Volumetric modules
| Module dimensions | Shipping size and finished size, if they differ at the mate line. |
|---|---|
| Mate-line work | Who closes the joint, the roof and the floor between boxes. |
| Lift | Pick points, weight and the crane the quote assumes. |
Panelized and flat-pack assemblies
| Packing | Panel count, crate size and what can be damaged by weather before the roof is on. |
|---|---|
| Site hours | Which trades the buyer must have waiting. |
| Tolerances | How the foundation interface is allowed to vary. |
Foldable bodies and steel-system links
| Unfolded footprint | Confirm the open dimension, not only the collapsed transport envelope. |
|---|---|
| Connections | Hinges, seals and any insulated metal panel that is added after opening. |
| When a steel building is the real need | Large clear span, tall eave height or a crane in the building may sit outside a room-module format. Say so instead of forcing the module quote to cover it. |
Standard layouts help when the project fits published module dimensions. A custom clear span or an unusual seismic design category needs project-specific engineering, and that engineering is not supplied by this page.
Worked comparison, not a test report: a 12 ft by 40 ft volumetric box may finish the interior before it ships, while the same floor area in panels may need a dry week on site. A foldable body can leave the plant inside a narrower transport envelope and still open to a wider room. None of those sentences is a pass-fail result. To check a quote, repeat the supplier’s stated weight, pick points, panel count and the wind speed they assumed, then ask the project engineer whether that assumption matches the site.
Method questions still open
Not by itself. Volumetric work can move weather risk off the pad and concentrate it into transport damage and lift day. Panelized work can do the opposite. The brief should say which risk the buyer is willing to manage.
Sometimes. Ask for two columns rather than a blended rate. Shell scope in one column and turnkey scope in the other still cannot be subtracted to invent a savings figure.
Ask whether the quoted welds, loads and quality documents refer to AWS D1.1, ASCE 7 or another named practice for that system and jurisdiction. A method label is not a certification.
Request a method comparison, not a slogan
- State volumetric, panelized, foldable or undecided.
- Add quantity, destination and requested delivery timing.
- Say whether the number should be shell or a wider scope.
- Leave code approval to the project team.