Is a gravel pad a good base for a container or expandable home?

A compacted gravel pad is a common site improvement, but it is a working surface, not a full foundation by itself. FEMA's manufactured home guide lists ground compaction, a layer of gravel, concrete runners or a slab as typical ways to improve the ground under a home. Gravel helps with drainage, keeps the pad from turning to mud during setting, and gives a stable base for pier footings. The home still needs proper footings or pads at each support point, the required clearance under the frame, and anchors against wind. HUD's installation standards require footings on firm, undisturbed soil or well-compacted fill, so gravel placed over loose or organic soil will not fix a weak subgrade. Ask your local building office whether it has rules for pad size or materials.

Check your local rule. This varies by state, county or city. Your permitting office has the final word; the official lookup pages below show you who that is.

Sources

• FEMA P-85, Protecting Manufactured Homes from Floods and Other HazardsFEMA
• 24 CFR Part 3285, Model Manufactured Home Installation Standards (2020 edition)U.S. Government Publishing Office (HUD regulation)