Cracks noticed!

Jojo24

Member
Oct 11, 2019
7
Massachusetts
I was home when they closed our 4 year old gunite pool. Normally i don’t see this process and the cover is put on for winter. I noticed some hairline cracks. See pics. The sub came over and said they will seal on their own once the pool is filled up again. To the touch they are smooth but an eye sore. Any thoughts are welcome.B0330C38-1EC8-426B-AF81-0D1FD481DBDC.jpeg
 

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Jojo24

Member
Oct 11, 2019
7
Massachusetts
I was home when they closed our 4 year old gunite pool. Normally i don’t see this process and the cover is put on for winter. I noticed some hairline cracks. See pics. The sub came over and said they will seal on their own once the pool is filled up again. To the touch they are smooth but an eye sore. Any thoughts are welcome.View attachment 120660
Curious why they haven’t dried out yet too.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
10,839
Northern NJ
The sub came over and said they will seal on their own once the pool is filled up again.
I don't expect the cracks. They will just become less visible with water covering them. How many cracks are there?

I would document where the cracks are and their size and keep an eye on them. If they change or expand then you have deeper problems.

Cracks can give a home to algae so watch those areas.
 

Jojo24

Member
Oct 11, 2019
7
Massachusetts
Thanks!
Again...haven’t really seen the pool with 12 inches drained out before. Maybe these have been present for a while. PB and Sub knows.
There’s about 5 of these hairline cracks.
 

Rich D

Bronze Supporter
Aug 3, 2018
583
MA
This is from summer. I can get a closer shot.
There's no picture posted.

So here's my theory. I have one of these as well very similar. Notice in the first picture where the crack seems to stop and the dark area stops but then a little bit below it the dark area is there again. My guess would be there as a crack in the gunite behind the plaster. It could just be a surface crack from shrinkage from the original build. Somehow water is getting behind the tile and going behind the plaster through this crack in the gunite. The crack seems to stop right around your winter draw down level. so I would assume the moisture is freezing in the crack and then causing the plaster to crack. I am by no means a plaster or gunite or crack specialist, but that is my theory.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
10,839
Northern NJ
Nothing you can do to affect the plaster and cracks.

I cant tell from the pics the condition of your grout around the tiles. Do you have any hairline cracks or missing or worn grout?
 

Rich D

Bronze Supporter
Aug 3, 2018
583
MA
Trying to upload but having issues. Think it will get worse? Anything to make it stop?

FYI..thanks for your feedback.
I would let the cracks dry out then try running a hose over the coping (not letting it go into the pool) to see if the cracks get wet again.

It does look like one of the coping joints is has separated. Check for any more that look like that. And try to see if the joint between the coping and patio needs to be re-sealed.

Another issue could be settling of the patio beside the coping leading to pooling water at that point. This is common if they did not do proper compaction on backfill of the pool. Get a small 6" level and place it the patio just next to the coping and see if you still have positive pitch away from the coping.