Design the Foundation
A gallon of water weighs about eight pounds. Multiply that by 30 gallons, add the weight of both your tub and a body, and you’re looking at a significant amount of weight. So a solid foundation is key to keeping your tub around for many years.
First, choose the bricks or stone pavers that will create the “floor” of your tub area. Then start digging. You’ll need to dig deep enough for an 8-inch layer of gravel and the depth of your bricks or pavers. For example: if your bricks are 3 inches thick, you’ll need to dig 11 inches total. This will allow your finished surface to be at ground level and will help prevent the bricks from buckling during our occasional winter freezes.
Once you’ve excavated to the appropriate depth, spread some quarter-minus gravel (crushed gravel in ¼-inch or smaller pieces). Use a tamping tool to level and compact the material (the flat side of a section of two-by-four makes a handy implement). Once your surface is flat and at the right height, lay your bricks snugly to create a solid, stable surface. Leaving a space approximately 10 inches square by 6 inches deep will allow for easy access to connect the drainpipe to the tub’s drain assembly (see illustration).
Note: To safeguard against damaging any underground sewer, water, gas, or electric lines, make sure you call the Oregon Utility Notification Center at 800-332-2344 to have your property’s utilities located. This is required for any excavation in your yard other than general garden tilling.