A hot tub is a luxury to have installed in your home, but it also creates some maintenance issues you'll have to deal with. One is the fact that hot tubs produce more steam and moisture in the air than a regular bathtub, which will play havoc on exposed plaster or drywall walls if you don't have a protective surround behind the hot tub. You can buy preformed fibreglass surrounds, but a classier solution for your hot tub is a real tile surround that you build yourself. It's important that the walls are solid and free of gloss before you start.
Measure one wall along the top rim of the hot tub. Find the middle. Use a carpenter's level and pencil to make a vertical line from the rim to the ceiling, right in the middle.
Spread tile adhesive along the whole width of the wall with an adhesive trowel, just above the rim. Make the adhesive section go higher than the height of a tile. The adhesive will cover the bottom of the vertical line, but you will be able to still view the line through the notched pattern in the adhesive.
Press one wall tile in place on one side of the vertical line. Put two spacers between the bottom edge of the tile and the hot tub rim.
Press additional tiles in place alongside the first, in a horizontal row along the top of the hot tub. Put spacers between the tiles and the hot tub, and on the sides of the tiles, to separate them from each other. Tile the whole bottom row, cutting the tiles on a wet saw to fit at the ends.
Install the next-highest row, just above the bottom row, again beginning at the centre line, and again working from the centre to the sides. Work your way up the wall in that fashion, row by row, using the wet saw as necessary to cut around any fixtures or obstructions on the wall. Tile each wall behind the hot tub in this manner.
Allow the adhesive to set for 12 hours.
Pull out all the spacers. Grout each wall by spreading the grout over the surface with a rubber grout float and forcing it into the lines between the tiles. Don't grout the lines at the edges of the wall, along the hot tub rim or in the vertical corners where the walls meet. Wipe up the residual grout with a damp sponge.
Allow the grout to set for two days. Run smooth, unbroken beads of caulk along the hot tub rim and in the vertical corners where the walls meet (the line you didn't grout earlier). Let the caulk set for a day before using the hot tub.