@ -469,7 +469,7 @@ static bool is_valid_building_site(building_site &site, bool orthogonal_check, b
if (bshape != tiletype_shape_basic::Open)
return false;
// Can build on top of a wall, but not on a constructed floor
df::coord pos_below = site.pos;
pos_below.z--;
if (!Maps::isValidTilePos(pos_below))