Before the deck can be built, mark off the designated area with spray paint. Then, use a backhoe, shovels and rakes to clear the area of brush and debris. To determine the size and shape of the deck, measure the dimensions of the hot tub.
Use these measurements to make a temporary frame out of 2x4's that will act as a guide for the deck's footers. This temporary frame will eventually be replaced by a permanent frame that is slightly larger to allow for expansion and contraction. Cover the ground inside the temporary frame with gravel to keep water away from the bottom of the hot tub.
Dig holes for the cement footers that will support the hot tub. Also, dig holes for the footers that will support the deck. Fill the holes with quick setting concrete mix and add water. Allow the concrete to dry.
Build the permanent frame for the deck out of 2x6 pressure-treated beams (Images 1 and 2). Pressure-treated wood is critical since the deck will be exposed to rain and the water from the hot tub, and pressure-treated lumber resists damage and deterioration from exposure to water or moisture. Once the frame is nailed together, it needs to be squared. Measure diagonally from corner to corner to determine if it is. You will also need to be sure that the hot tub frame is centered with the exterior frame of the deck. Tie nylon string diagonally from corner to corner of the exterior frame. Then, shift hot tub frame until the corners line up with the nylon string. Determine how much extra room will be needed to allow for the deck to expand and contract. Now you are ready to replace the hot tub’s temporary frame with a permanent frame (Image 3).
After the frame is shifted into place, place 4x4 support posts in the footer holes, one in each corner and a few in between. Then, drill each support post to the frame with coated deck screws.
When the inner frame is squared and centered, attach the frames to one another with several 2x6 joists. These joists will act as supports for the deck. Attach a right angle bracket to the base of each support post. Because the posts are set in concrete, first drill pilot holes, and then secure the brackets with concrete screws.