If you are planning on installing a deck surrounding a hot tub or spa that is set on top of a concrete pad you will need to create an access hatch for the hot tub electrical hookup, pump, and controls. In order to do this you will have to frame out an opening in front of the hot tub access panel. A 4' x 4' area will usually give you enough space to perform any maintenance work on the hot tub. You will need to build a 4'x4' removable panel that will be supported on each corner. Frame the panel with a double rim and joists 16" on center. Install decking over the framing in the same direction as the deck floor. Install latches or hinges to secure the panel to the deck floor. Make sure the hatch is secure and level with the deck floor.