How Do I Trowel the Pool's Base?
Keep the base at least 1.5 inches thick, and trowel shallow to deep so crumbs finish in one corner rather than under your liner.
Troweling sets the surface your liner sits on for the life of the pool. Crumbs left in the base show through the liner once it is installed, and you cannot sweep them out until the bottom has cured.
Decide which direction you are working
Trowel shallow to deep. Working this way lets you drive crumbs and debris ahead of you toward a final corner of the hopper.
Working deep to shallow makes it difficult to keep crumbs out of the finished bottom.
This is decided before you start and it is hard to undo, because debris cannot be swept out until the bottom has cured.
What you need
- A flat shovel for spreading.
- A 30 inch magnesium darby or a 16 inch pool trowel.
Troweling the base
- Keep a minimum thickness of 1.5 inches throughout.
- Spread the material with a flat shovel into roughly 2 foot by 6 foot sections, then flatten it with the darby or trowel. Work in several directions to get it as flat, even and smooth as you can.
- At the base of the hopper walls, bring the material 2 inches up the pool wall to the set string.
- Avoid sharp edges and pockets in the pool bottom. They collect dirt once the pool is filled.
- Trowel out crumbs as you go rather than leaving them for later.
- Trowel the deep end walls first, then the floor around the drain, then work your way onto the ladder board.
Finishing up
- Remove all strings and stakes from the bottom once the deep end slopes and hopper are troweled, then smooth those spots.
- Bring the bottom up to finish grade with a damp sand and cement mixture, or vermiculite and cement, and trowel it smooth.
- Leave the pool carefully to avoid disturbing crumbs, and lift the ladder and board out with two people.
- Wipe the walls clean, then check the bottom for stones, twigs and any sharp objects and remove them.
Before the liner goes in
Most vermiculite mixes are not ready to walk on for 24 to 48 hours, which delays liner installation. Plan for it.
The liner can go in on a wet or dry floor, but if the weather and your schedule allow, let the floor dry completely first.
Once the base is ready, see how to install an inground pool liner.
For the full walkthrough, read our guide to troweling your pool base.
Still need help?
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