[tentcamper]

Im under the impression there is a 2x4 along the outer edge. The floor is laminated aluminum, thin plywood (1/8 or 1/4), Styrofoam about 3" , thin plywood (1/8 or 1/4), aluminum. Some areas don't have the Styrofoam because there are wire and pluming channels cut out of the Styrofoam.

Except for the outer edges, I don't think I would be using lags.