Help! Tile & Cracked Plaster Repair Questions

Hi All,

Just took the winter cover off my concrete plaster pool here in Massachusetts and discovered a number of tiles have fallen off at the waterline and a previously patched crack has reappeared with a vengeance! I've only had this house with the pool for a couple of years so I'm new to the concept of the expansion gap/joint around the pool and I think this pool damage is probably caused by my neglect of the crumbling caulk and water seeping in over winter, causing the deck to push against the coping, beam, etc.

I've decided to re-tile, patch the plaster, and recaulk the expansion gap to see if it will hold up for at least a few years before a major overhaul down the line.

A couple of questions:

1) I was thinking of rigging a makeshift scaffold in the water like I did last year when I plastered a smaller version of the crack. Do we think that's wise? I was hoping to avoid draining the pool completely and the hassle of getting it refilled, but if I'm going to be working with power tools over water... maybe not such a good idea? Also, there's already a fair amount of debris in the water, cracked tiles, plaster, etc. If I don't drain, how can I get all that stuff out of the water when the repairs are done?

2) It looks like the crack appears in the concrete underneath the plaster/tile thinset as well, what should I use to patch the crack in the concrete layer? What can I use that will strengthen and stabilize that layer?

3) Underneath the crumbling caulk in the expansion gap is a couple inches deep band of foam. I was planning to replace it all with backing rod, should I double decker the stuff to make up the depth difference? Or should I pour sand in the gap as some places have suggested? Thoughts?

4) Any thoughts on Vulkem 116 caulk vs. Vulkem 45 specially designed for pool expansion? Is the 45 worth the added expense?

The most common cause of tile line failure is inadequate design for expansion and contraction. During major temperature changes, everything shrinks & expands, but the pool wall moves along a vertical axis or line, while the pool deck moves along a horizontal axis or line.

Proper design isolates the coping or pool edge section from the deck, allowing to move vertically with the pool wall, and remain independent of the deck. However, it is VERY common to install the coping or pool edge so it is continuous with the deck. This inevitably results in damage along the tile line, especially when temperature changes are extreme.

If this is the case with your pool, all repairs are simply temporary patches, until the vertical/horizontal expansion issue is corrected.

Repairing cracks in the shell can be minor -- but if they penetrate the shell, they are usually major and require serious effort to correct. If they are caused by subsurface movement or settlement, it's necessary to stabilizer the ground underneath before making any permanent repair to the shell.

There are multiple methods to repair each of these issues: what's best depends on the skills of the worker, and what's available locally.

. . . membership updated.