Why does tile fall off of swimming pools?

In the north east region of the United States, cold weather allows for freezing conditions causing more tile and coping damage than in warmer regions of the country. Over the winter, in-ground pools are closed and winterized for protection. Pools must be closed properly and checked periodically over the winter.

Underground Damage

Ice damage is the number one cause of tile and coping failure. It may sound absurd, but the goal is to keep water away from your pool. Most pools have some type of a coping stone on top of the pool shell and a solid concrete deck around the pool. When this is the case, there should be an expansion joint between the coping and the decking. This expansion joint seperates the pool from the deck allowing them to move independantly. This keeps the decking, which moves with the freezing and thawing of the soil below it, from pushing on the pool which could cause damage to the shell, tile and/or coping.

The expansion joint should be sealed with a solid, flexible material such as a polyurethane caulk. This caulk will prevent water from entering the expansion joint, limiting the chance of ice damage. Foam, wood, or sand will not stop water penetration and are not suitable for this application. Caulk should be inspected for voids every year when you open and close your pool and patched with a compatible sealant. The maximum lifespan of caulk is five years.

Damage from within the pool

During the winter months, the water level should be lowered and maintained to approximately three inches below the bottom of the tile line. Lower than suggested water levels may damage your plaster while higher levels may damage your coping and tile. If the water level is above the tile line and the surface freezes and expands, it can push against the tile and coping causing tile to crack and coping to lift.

Pool tiles are also subjected to normal wear and tear and pool chemicals. It is normal for pool tile and grout to fade, discolor, crack, or become pitted over time.

Cantilever Decks

tilefall2A pool that has a cantilever deck has no coping. Instead, the concrete deck is brought right up to the pool’s edge for a more seamless look.  All concrete decking is prone to movement caused by settlement or the constant freezing and thawing of the soil below it during the winter months. The cantilever deck is no exception. For this reason, a cantilever must be installed so that it does not directly touch the pool shell or tile. This is accomplished by incorporating an expansion joint or gap between the top of the pool shell and the bottom of the deck. This expansion joint is hidden by a white plastic strip that protrudes from the bottom of the cantilver deck edge and extends down to cover the top 1/4 inch of the tile. Without this expansion joint, deck movement would transfer pressure directly to the pool shell which would cause damage to the pool structure and the tile.  When replacing tile on a pool that has a cantilever deck, it is necessary to break out the plastic strip in order to gain access to the full height of the tile line. Just like the original tile, the new tile must be installed so that it is not touching the deck. Once the original plastic strip has been broken it can not be replaced, so the expansion joint is now filled with a polyurethane caulk which seals the joint while still allowing for expansion.

Spa Walls

Some pools have built in spas which are usually separated by a “spa wall”. tilefall3Spa walls are constructed using rebar rod and gunite just like any other pool wall with one exception. Pool walls are formed using the earth as a backer against which the gunite is shot. It is important that the gunite be shot against a surface that doesn’t move or vibrate and the earth serves this purpose very well. Unfortunately, when shooting a spa wall there is no earth to shoot against. Instead, temporary walls are created using plywood and lumber which vibrate when the gunite is shot. This back and forth movement of the plywood form creates voids around the rebar rod in the spa wall producing a sub-par product. Over the course of it’s lifetime the wall is subjected to freeze/thaw conditions which cause movement, making the wall weaker with each passing year until it eventually cracks or the tile falls off. Original spa wall tile typically lasts 5 to 10 years. Replacement spa wall tile may last 1 to 10 years depending on the condition of the wall itself. Unfortunately, we have no way to determine the condition of a spa wall other than a visual inspection. Replacement of a wall involves restructuring of the pool shell and is an extremely costly undertaking.