Spa plaster delamination

[kornkid42]

Hi Everyone,

See pic. Plaster at the bottom of my spa is coming off.

What could be the cause?
Can it be fixed? By me?

 

[shuye]

I can't help directly, but here are a few questions that might provide more info:

1. How old is the pool / plaster if re-plastered
2. How do you chlorinate the pool? SWG, Bleach, Pucks?
3. Is this only happening in the spa, or are there places in the pool also?
4. Does the water in the spa circulate on a regular basis?

 

[kornkid42]

pool was built in 1999. Don't know if it was ever replastered, i've owned the home for 4 years.

I used to chlorinate with liquid chlorine, using pucks since last year. The spa jets run during the day, but not the drain. After thinking about it, i'm wondering if the ph level gets too low when i add acid to the pool since the drain is not on.

 

[onBalance]

The plaster flaking is known by plasterers as "spalling" or "delamination." The upper one-sixteenth inch surface is flaking off. The overall thickness of the spa floor is usually as least a half inch. The delamination is caused by improper troweling, usually adding too much water to the hardening surface too late in the process. Water chemistry has nothing to do with that occuring. The defects were there at the begining, a slight bonding problem, but not severe enough to flake off soon after filling. It usually take some time, temperature changes, or the draining and drying out will cause it to shrink and lose its bond.

It is very difficult to patch with cement, but power sanding may smooth out the rough edges and rough center areas. But that will be a lot of hard work.

 

[jlentz32]

I'm having delamination issues in my spa as well as some small areas in the pool. (a corner on the sun shelf). My pool was empty for about 2 weeks in mid March. I started noticing issues shortly after refilling.

I was a bit more aggressive than I should have been with the MA to get the TA down. Could that have been an issue? I believe the plaster is about 10 years old. Plaster has always been a bit rough in the spa but I was told that was normal. The Delamination started around some of the jets, Later I've noticed it developing on the walls of the spa, most areas are around 1-2" square.

I seem to recall seeing that EZ-Patch made something to patch up plaster. Has anyone had any luck with it?

 

[onBalance]

No, adding acid does not cause delamination.
There was an original weakness in bonding in those areas at the time of plastering. When the pool or spa is drained and the plaster is allowed to dry out for a while, there will be some expansion and contraction of the plaster surface. That will cause the plaster layer to separate. Generally, over troweling creates those conditions.
EZ patch might work okay, but also sanding with sandpaper will smooth up those areas. But that would be a lot of work.