How to Build a Spa Surround for a Sunk Spa

Seal the perimeter of the spa, whether it's decking, exposed aggregate or slate. Any permeable surface must be sealed thoroughly with a waterproofing.

Lay ten 2 by 4-inch cedar studs or 8-foot pieces of decking on their edge. Milled lumber is 1/2 smaller, so the edge will be 1 1/2 inches. Align the ends of one side flush with the end of a 6 foot square spa. The other ends of the ten 2 by 4 boards will extend past the opposing edge of the spa. The four sides of the deck will continue around the spa in this overlapping brick pattern.

Rip 3/4-inch strips of cedar from one 8-foot cedar board on a table saw. Cut three or four full 8-foot strips.

Cut the 3/4-inch strips into lots of 1 1/2 inch pieces to be used for spacers.

Mark two light pencil lines along the tops of the ten evenly aligned boards. The lines should be 2 1/2 feet from each end.

Spread the boards out a little. Put a couple dots of wood glue on two spacers. Place the spacers against the board on the end, with one spacer centered on each line. Nail the spacers in place with a pneumatic air nailer, using two 2-inch galvanized wire brads per spacer.

Glue the ends of the installed spacers and nail the next board in place making sure the ends are aligned.

Glue and nail each board together with spacers between them, centered on your lines.

Cleanup any excess glue with a damp rag.

With a carpenters file or medium sandpaper, sand the edges of the board-ends so they match the milled radius of the rest of the boards.

Construct three more identical lengths of the deck.

Set the four deck pieces in place using the lapped brick pattern.

Cut 12 lengths of 4 by 4-inch cedar. Cleanup any milll splinters from your chop-saw using a carpenters file.

Lift the sections, one at a time, placing one 4 by 4 under each row of spacers -- two on each side of the spa. Set another 4 by 4 section under each joint where two sections lap. There's no need to permanently fasten these in place. Water can drain through them. You can walk on them with firm footing or sit on them if you get too hot, and it's still an easy step into the spa.