How to Repair Cracks in Plaster in a Gunite Pool
Filling small cracks in the plaster of a gunite pool helps to avoid large amount of water loss during the swimming season. Sealing a crack in a gunite pool, under the water without draining down the pool, is possible. Draining a gunite pool is not always a good idea, so it is best to avoid. When I first got my gunite pool I thought there would be no more pool maintenance. A gunite pool is a huge step up from a pool with a liner. While the pool itself needs very little maintenance, the pool contractor did one thing wrong during construction which now requires some work every year. The contractor did not properly support the skimmer box. It looks like the location had some fill pushed to this area that probably did not have time to settle during construction of the pool. This causes the plaster between the pool and skimmer box to crack each winter during the freeze-thaw cycle in the ground. The crack is wide enough that it causes water to leak out underground. Repairing this area in the plaster is required each year to avoid water loss through the swimming season.
Here is how to patch cracks in a gunite pool
- Find all the cracks in the plaster coating. The best way to do this is to inspect the finish under the water with a snorkel mask.
- Use a brush with stiff plastic or soft metal bristles to clean the plaster surface around the cracks.
- Use a high quality two-part epoxy that will set underwater. The first Spring I noticed the cracks in the gunite I went to a pool supply store to find a solution. They sold me a $20 tube of cheap two-part epoxy putty. After applying the epoxy putty underwater, I temporarily sealed the leaks in the pool. By August, however, the water leaking again returned. I inspected the crack fill attempt and found that it again cracked and was coming off the surface of the plaster. I let it go by continuing to add water for the rest of the summer to a find a new solution. By the next spring, the old “epoxy” was easily peeling off the pool. This was the stuff that the pool supply owner said worked great on his pool. I was very careful to mix the epoxy, so I know it was not a construction problem. I then used a putty knife to remove all of the old epoxy material from the crack area. Then, I found a new epoxy material that had very good ratings for a variety of applications. It is called Apoxie Fix It Sculpt from Ames Studios. Fix It Sculpt is a 2-part expoy. When it is mixed it becomes like sticky clay. It is safe to handle according to the labeling and sets up underwater in 24 hours. I used my fingers to push the epoxy over the cracks and match the surface of the plaster. The Fix It Sculpt material holds up very well while underwater. The Fix It material is now by choice for repairing cracks that appear in the spring near the pool skimmer box. I apply it once a year and do not have any more problems with leaks. This material is so good that I have began using it around the house for bonding and repairing different items.
- Once the crack filler is applied, turn off the pool pumps for 24 hours to allow the epoxy to cure. This work is best performed