Whether you have a pool or not to complement your spa a deck can be an perfect location because it offers an elevated, clean, flat surface on which to dry off after relaxing in your hot tube. Building a deck to support a spa is very different that assembling an ordinary deck since the weight that it needs to support is a great deal more. It must be sturdy and strong.
You will need treated wooden planks for piers and footing, measuring tape, shovel, stakes, sand, and saw.
The usual deck measures about 8´x 8´. Mark your perimeter with stakes and string. Determine the center of your deck area by using the meeting point of strings that are strung diagonally between the stakes, from one corner to the other. Now mark this point with another stake. Mark all of the other locations of pier footings with stakes. On a deck of this size (8´x8´) there will be 13 of these. One for the center, four for the corners and 4 placed at the center point of each side and the last four placed between these and the center stake.
Now you will need to dig square holes at each side of the pier footing locations, at least two feet deep with a thin layer of sand ( about 3”) over the bottom of the holes. Level and compact the sand. Place the pier footings vertically on the inside, assuring yourself that they are firmly set and level, then pound down the soil around the footings. Add enough soil at the base of each footing to allow overflow water to run away and not form puddles around your deck once the tub is installed.
Cut all of your wood to the proper length, 8´x4´ in this case, which is easily done by attaching two 8´x2´s boards, shaped so that they fit easily together. Secure the deck´s support frame over the pier footings. Use metal T-plates to fasten the wood boards together atop the support pillars.
Secure the flooring of your deck to the support frame. Screw 2”x4” planks over the support frame, and leave a tiny gap between each board. To keep your structure safe, be sure to countersink all of your screws. Coat your deck with weather-proof stain and finish. Sprinkle some sand onto the finish before you spread it to create a nonslip surface in case water slips out of the tub. Allow the finish to dry and install the plumbing, electrical and tub itself and your ready to enjoy.