How to Build a Jacuzzi Tub in a Basement Floor

Dig a hole for your concrete base. Use an electric saw to get through wooden floorboards and a jackhammer if the basement floor is made of concrete. The depth, length and width of the hole will vary depending on the Jacuzzi tub model you want to install. Your hole will be about the same height as the outside Jacuzzi frame, but you will need to take into account the width of the cinderblocks used for the dimensions of the length and width.

Make changes to your home's plumbing, drainage system and electrical wiring at this time if needed. It is best to contract the services of professionals, particularly if you do not have much experience plumbing or wiring a home.

Compact the dirt at the bottom of the hole you dug with a dirt compactor. Because of the weight of the water, it is important to construct a concrete base on 6 inches of compact soil that can handle a PSI load of at least 1,000 pounds. Use No. 4 rebars spaced 18 inches on center in the compacted soil.

Pour in 5 inches of concrete into the hole you dug, minding any new plumbing and electrical installations, and allow it to cure.

Place cinderblocks along the perimeter of the concrete pad, securing them with mortar. The cinderblocks act as an extra layer of support for the Jacuzzi. Starting in one corner of the hole, on top of the concrete pad, place enough mortar on the edge of the concrete to lay three cinderblocks next to each other. Use a level to make sure the cinderblocks are even and a ruler to make sure the blocks are 1/4-inch apart. Make sure mortar is between each cinderblock. Continue this process around the perimeter of the concrete pad, scraping off the excess mortar as you work. When you begin laying the next row of cinderblocks, center the first block you lay on the first 1/4-inch gap of the row below so the blocks do not line up vertically. Keep using mortar between the cinderblocks to secure them, taking care to scrape off the excess with the trowel. Continue to lay all the cinderblocks in the same fashion until the blocks reach the top of the hole. Allow the mortar to cure.

Coat the concrete and cinderblocks with Gunite, a type of waterproof plaster that will help protect your home from water damage if the Jacuzzi springs a leak. Use the trowel to smooth the Gunite. Allow the Gunite to dry.

Place the Jacuzzi tub into the hole. Because of the weight and size of a fully built tub, you may need to assemble it on site.