You can construct hot-tub decks, walls and entire hot-tub structures out of landscaping blocks.
Block Walls
One of the easiest ways to build a hot tub out of landscaping blocks is by first installing the hot-tub shell, then building walls out of landscaping blocks that surround the tub. With a concrete saw, cut away parts of the bricks that cover the fill line and outlet for water. This is similar to the process of installing wood or poured concrete walls around a prefabricated tub to give it a custom look. You can use the same blocks to pave the area around the hot tub's base, making it appear to rise up out of the ground.
Block Tubs
You can construct the entire form of a hot tub using landscaping blocks. For this type of project you'll need to start with a smooth concrete base. Build up the blocks using a lime-based mortar, producing first the walls of the hot tub, then any interior features such as bench seats and steps. Since the landscaping blocks and mortar won't be able to hold the water in, you must also install a liner, covering the blocks from view. Landscaping blocks are usually expensive, which means that pouring concrete to form a hot tub is a more affordable alternative that produces similar results.
Paving With Blocks
In some designs, a hot tub is sunken beneath the level of a deck or patio, making it easy to climb in, and eliminating the need to construct walls around the tub. In this case, you can still accent your hot tub and integrate it into your yard using landscaping blocks. Lay blocks around the rim of the hot tub or use them to create a path from your door directly to the tub. Cut away portions of blocks where you need to mount a handrail for entering and getting out of the tub.
Working With Landscaping Blocks
Landscaping blocks come in many different colors and styles. While some take the form of squares and rectangles, others have interlocking shapes that allow them to join together at a variety of angles with only small gaps between blocks. Once you mix up the mortar, you'll need to work quickly before it dries, so be sure to have more landscaping blocks than you need on hand, with a rough idea of how they'll fit together.