Porcelain Tile for waterline

[psycgirl]

Is it okay to use an outdoor rated porcelain tile for the pool waterline?

My pool guy wants me to buy tile through him, but the pool offerings are really ugly and I can get pretty tile at a good price as a remodeler.

[PoolDoc]

What you are looking for is tile that is described as "frostproof".

Because pool tile tends to be half-submerged throughout the season, if it absorbs ANY moisture at all, it will crack if it freezes.

Of course, the most common mode of tile failure, since the replacement of "pool coping stones" with "cantilevered decks" 30 years ago has been the appearance of expansion joint cracks that often split the tiles, along a horizontal, irregular line around much of the pool. This sort of failure will INEVITABLY take place, unless the pool WALL (including the tile) is COMPLETELY isolated from the pool DECK using a full depth rubber, plastic, etc "expansion joint"

The reason is, during temperature changes the DECK expands and contracts horizontally (parallel to the ground), while the pool WALLS expand and contract vertically (up and down). The forces generated during this movement are HUGE, and even though the movements are small, dimensionally, they are still large enough to crack the pool at the weak point in the joining, which is typically underneath the tile.

If you want to check your builders ability to avoid this (most don't know how), ask to seek several of his pools built at least 3 years ago. If the tile lines on THOSE pools are OK, yours probably will be, too.

Good luck.

[psycgirl]

Thanks! This makes sense. They are doing an expansion joint so I should be good.

[PoolDoc]

Not necessarily: it must be a FULL DEPTH expansion joint, with no concrete to concrete contact at any point.

Many "expansion joints" are really 'crack control joints' and are NOT full depth.