What's our pool made of and why is it doing this??

[tj__r]

OK, so I've got an extreme knowledge deficit. We just moved in a couple weeks ago, never had a pool before, never really even looked too hard at other people's pools. These pictures:
[attachment=2:1u9g1otc]DSC03130.JPG[/attachment:1u9g1otc] [attachment=1:1u9g1otc]DSC03131.JPG[/attachment:1u9g1otc][attachment=0:1u9g1otc]DSC03132.JPG[/attachment:1u9g1otc]
show the sides of our pool. Walls are vertical, some sort of curved (like vertical cylindrical sections) panels with little blue gasket material between, approx 3' deep. They meet a bottom ledge at a right angle, then the bottom, which is apparently concrete or plaster, has a curved slope like a big freeform bowl. Can you guys tell me what type of construction this is?

Now the trouble, I think. There's domes or blisters on the vertical panels about 1" or 1.5" diameter and 1/8" or so thick. Some are just dome shaped, some have tiny cracks that look rusty. Are they likely to be leaking? Do we have a big mess?

Thanx in advance!

 

[tj__r]

I guess it's fiberglass walls with a concrete bottom - similar to the pieces shown in this post. Have not found a posting showing anything like our blisters tho.

I suppose we need to test with some food color and a syringe.

 

[aherber08]

Hey I have the exact same pool! Had the same problem with the blisters. Just out of curiosity, do you know when the pool was built? Mine's from the late 70's. I was very thorough in researching the problem, and talked with lots of pool builders/repair people. I believe they all told me that the blisters are unlikely to leak, as it's just the gelcoat of the fiberglass that is failing, not the glass fibers underneath. From either the front or back, water is able to get between the gelcoat and the glass fibers, and forms a blister. The slits are where the blister has popped. When my pool was drained, I could squeeze/scrape them, and water would come out. Problem is, eventually (over years) the water/chemicals do start to degrade the fibers too. I discovered this with my pool, which had the blisters for many years before I bought it...some of the worst ones had fiber damage behind them. I should mention that I didn't have the money for a professional job, so many people encouraged me to pursue fixing the gelcoat myself....also I couldn't find anyone in northern Indiana that worked on these pools. There are youtube videos out there of people repairing gelcoat themselves.

I ended up scraping off the blisters and sanding my panels, and patching with a 2-part epoxy repair compound that said it was for boats/pools and could be painted, but it wasn't a gelcoat. Had the concrete bowl professionally sandblasted (as it has been painted, and the plaster had worn down to the concrete in places). Then I painted the whole thing with epoxy primer and paint. So far, so good, but it's only been a month, so it's too soon to tell. I realize that this may not be the best approach. I'M NOT advocating this for everyone. (I know that paint is a shorter term fix, and many people much smarter than me on here are (rightfully) opposed to it.)

But, I'm not an expert, just a fellow pool owner. Hopefully someone on here can be a better help.

 

[tj__r]

Ours was built sometime in the 1990s. Good to know that it may not be leaking there...will still need to find the fairly bad leak (about 1" every day.) I suppose we need to look into re-gelcoating if we can find somebody to do it. We're north of Chicago so not too far from you.

I don't think the blisters looked as rusty when we moved in, but maybe the previous owner had used some sort of rust remover when they were showing the place. And I guess they figured we wouldn't notice the leaking

Just out of curiosity, it looks like you have a drain fitting in your picture. Did you wind up plugging it?

 

[aherber08]

I was told that the stains can be from the chemicals of the gelcoat/fiberglass reacting with the water, but also rust is possible. Brushing may help keep the stains down a bit. Before this year I wasn't on the BBB method, and always ended up with algae growing on/in the slits by the end of the summer. And yes, good catch on the main drain...the pool was built with one, but at some point (before we bought the house) the line from the drain to the pump cracked underground, and the only thing to do was plug the line...couldn't spend big $$$$ tearing up the yard to dig down to it.

Good luck leak hunting. Hope it's not your main drain I think you'll find good advice on here for tracking it down. Once you've ruled out all of the lines, start with the food coloring test around your light, main drain fitting, and then all those gaskets between the fiberglass panels. Just my 2 cents.