The kit’s placement check rejects interiors: “MUST PLACE ON GROUND” and “CAN’T PLACE ON SURFACE” appear when you try a floor inside a structure, and main bases are excluded entirely. The community has found one warehouse on Bakurani that accepts a kit; treat it as a bug that may close.
What you can do instead:
| Goal | How |
|---|---|
| Use a warehouse as a wall | Deploy the FOB in the yard beside it; the ≈ 60 m zone reaches inside, so HESCO and doors can be placed on the warehouse floor as long as the console itself is outside. |
| Fortify a room without a FOB | Sandbag walls, barbed wire, hedgehogs and recon tents need no FOB and no zone; the Small hammer places them from backpack supplies. |
| Block a stairwell or doorway | Sandbags plus wire, or a hedgehog in a vehicle door. Doors and gates are FOB-tier and need the zone. |
| Lock a map tower | Build around the tower’s ground entrances from outside; the interior stays unbuildable (see the tower-lock blueprints). |
Other placement errors you will meet: “FOUNDATION(S) OBSTRUCTED” (a prop or slope under the footprint; toggle snapping with B or move a cell), “CAN’T PLACE ON IN-BUILT BUILDABLE” (stacking on a piece that does not support it, such as a Bremer wall), “CAN’T PLACE NEAR LADDER” (move the tower, not the wall), “MUST PLACE IN CONTROL ZONE” (drill rig outside the zone).
The spawn shield is the FOBplans answer to “I want a roof”: an Indirect Fire Shelter inside your own ring instead of a building you cannot build in.
squad-spawn-shield-ifssolo-pocket-fobmodule-recon-nesthow-to-buildairlocks-doors-gates
Sources: allthings-cluster · steam-skivin · keengamer-fob · fobplans-research