Corners, and the last corner

There is one key difference between the first corner (see "Placing the first two panels") and all subsequent corners: the last wall panel reaching into the corner often has to be trimmed to fit. The reason: walls tend to "grow" in length during installation. Consider a 32-foot wall with four 8-foot panels in it; assuming there is a 3/16" gap at each panel joint, the last panel will overhang the floor by 3/4 of an inch. In this case you need to cut the 3/4" off each facing, then use a hot knife to melt the EPS foam back far enough to accept the 2x vertical end plate. (With urethane panels, use a router to recess the foam for the plate.)

Except in the last corner, actual panel assembly at each corner goes the same as the first one. Use a thick bead of adhesive between the facing and end plate of the two corner panels. At two-foot centers, drive long screw fasteners--two inches longer than the panel width-through the outside facing of one corner panel. Recheck for level, then screw the fastener into the end plate of the other corner panel. Make sure the screws draw the panels tightly together; you shouldn't be able to see any daylight through the joint.

If you order panels with the exterior facing doubling as an exterior finish (e.g., T-1-11 siding), manufacturers will make a special panel for corners. Typically, the finished outside facing material must extend past the full width of the other corner panel, running outside it. When using this system, you need to slightly modify your plate layout at each exterior corner; in each case one of the two bottom plates needs to be held back the thickness of the exterior facing from the outside edge of the floor deck.but it has to be the correct plate, dependent upon which one the manufacturer supplies with the extended facing.

The gap between these two corder panels is unacceptable; this corner needed more tightening, or at least a good shim on the end-plate so that the connection included full adhesive, not just screws acreoss a small gap.

With the last corner, just make sure that the last panel you place is the one that runs to the outer edge of your floor deck, not the one that runs flush up the other corner panel. Otherwise, you're stuck with shoving the spline down from the top of the joint; that prevents effective use of caulk and adhesive at the last panel joints-an unacceptable approach.