Vermiculite is a mineral often mixed with concrete and used in the construction of pool bases and other building projects requiring a solid floor. It can also be used to soundproof rooms as well as be added to potting soil. Vermiculite pool bases can become cracked and damaged over time, which is usually caused by a puncture from inside the pool. Repairing minor cracks and gouges in a vermiculite pool base can be done at home without professional assistance.
Drain all the water out of the pool by placing a submersible pump into the deepest end of the pool and turning it on. Drain the pool water into the sewer line, which is usually located in the front yard of a home and has a square plastic cap on top. Use a wrench to open the cap, and attach the hose from the submersible pump to the pipe.
Remove the pool liner as directed by the manufacturer's instructions.
Examine the vermiculite base to determine the extent of the damage. If there are broken chunks of vermiculite, remove them with your hands and discard. Sweep the entire pool floor with a broom to remove all dirt, debris and smaller pieces of vermiculite.
Pour one part of vermiculite powder and three parts of cement into a five-gallon bucket. Slowly add water to the mixture until you achieve a thick mud-like consistency.
Gather some vermiculite onto a trowel, and place it onto the damaged section of the pool floor. Scrape the trowel across the floor to fill the damaged area, and smooth the vermiculite out in an even layer. Try to get the vermiculite to the same level as the original floor.
Allow the vermiculite to harden and cure for two days prior to reinstalling the pool liner.