Swimming Pool Blog

Swimming Pool Caulking and Expansion Joints

by John, December 26, 2008 



Almost all in ground pools have an expansion joint. The pool expansion joint is the gap in between the coping stones and the pool deck. Usually filled with caulk, this joint allows for movement of the pool or pool deck without cracking either. If the concrete were to be poured right up the coping stones, the coping stones and concrete deck would crack and break when the deck expands with warm weather.
That’s why we have expansion joints around the pool, to allow for expansion of the pool and deck. If your pool is new, you may see a foam strip installed when the deck was poured, separating the deck from the coping stones. This is your “perimeter expansion” joint. If you have an expansion joint that runs from the pool “out” then that is your lateral “expansion” joint.
Why Do We Caulk Our Pool?
One of the strongest forces of nature is ice. Basically, nothing can stop it. When water freezes, it will expand with great force. Ice can break steel, concrete, rock and just about anything else that gets in its way. So, if you have a slab of concrete and water gets under it, freezes and turns into ice, that slab will rise.
To protect your pool investment, it is necessary to seal all gaps that water can penetrate. If water gets behind coping, and the tile band, and freezes, the tile and coping can become damaged. The pressure of the ice can push the tile out, cracking it. This can be very costly.
Another reason to caulk the pool is that without a barrier, the expansion joint will eventually fill up with sand, grit, etc. Sand has very little compressive ability. When the expansion joint is full of sand, guess what? Very little expansion can take place. So, if you were ever in doubt about whether to caulk the pool or not, do it. It can save you money in the long run. So, get out there and caulk the pool, before the harshest winter weather sets in.

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