Choose the foundation as part of the house
A basement can add usable space and mechanical access, while a crawlspace or slab may reduce excavation. Climate, soils, groundwater, accessibility and local practice all affect the choice.
The module bearing points, marriage line, beams, posts, openings and stair locations must align with the approved foundation design.
Control tolerances
Factory modules are built to drawings with specific dimensions. Foundation level, squareness, anchor locations and penetrations should be surveyed or measured before delivery.
Correcting a foundation after modules arrive can be costly and unsafe. Define who verifies readiness and who accepts the measurements.
Manage moisture and energy
Waterproofing, drainage, insulation, air sealing and radon measures belong in the foundation plan. Basements also need coordinated egress, fire separation and mechanical systems.
Temporary weather protection matters between foundation completion and the set, especially where snow or heavy rain can collect inside.
Apply this guide to a real project
For foundations: basements, crawlspaces and slabs, create a dated project note tied to the destination address and current drawing revision. Identify the authority, designer, factory or contractor responsible for each unresolved item. Attach the written evidence for ‘Which foundation type is permitted and engineered for this site?’ and ‘How are module loads and the marriage line supported?’ rather than recording a verbal assurance.
Before a deposit, production release, shipment or final payment, convert every open question into a named action with an owner and deadline. Keep superseded drawings and decisions in the record so later inspectors, lenders, insurers and future owners can understand why the completed house differs from an early sales plan.
Questions to resolve before proceeding
- Which foundation type is permitted and engineered for this site?
- How are module loads and the marriage line supported?
- Who confirms level, dimensions and anchor locations before shipping?
- What waterproofing, radon and drainage measures are required?