Here's what went on behind my 8 year old liner...

[Shelley N]

I decided to replace the liner after getting a hole along a seam in the bottom last year. We repaired it but see evidence of rust on the sides here and there. We left it uncovered over the winter in anticipation of the event and it surprised us that it lost less water than in all the years we covered it! It did get nice and green for spring along with the yard when we typically open to crystal clear when covered.

What surprised me most was the fact that after being drained it is soaking wet under the entire liner. I mean REALLY wet. For years I had a ring of damp dirt around the pool like in the first pic. My neighbor told me that was from condensation. We didn't think we had a leak so took it for normal.

The next image is the spot that really bugged me. When you ran your finger over it it seeped a little. The next pic is what it looks like on the INSIDE of that spot after draining! The liner is different in that spot and I can see a tiny hole. The next pic is what it looks like running the entire side of the liner. I just can't believe this is normal--surely this is a defective wall???

Another thing I did not expect is the bottom of the liner feels thin, hard and brittle while the sides still feel soft and maleable like the day we got it. Has anyone else noticed this with an old liner?

I'm always curious about this stuff, so if this helps anyone, I'm happy.

 

[Metallica]

I too wonder how galvanized steel rusts. It has a coating over the entire wall that prevents rusting yet it still rusts. Can anyone elaborate? Also, the liner being brittle is perfectly normal for a liner of that age.

 

[JasonLion]

Liners do get less flexible and eventually brittle as they age. It is common enough for this to happen more in some places than in others. They can also get small holes in them, and if you don't find the holes fairly quickly you will get rust on the wall panels.

 

[Metallica]

Jason how do galvanized steel pool walls rust? I've been wondering this for awhile. Not hijacking this thread or anything, it relates to the topic.

 

[frustratedpoolmom]

Can't speak to the defective wall but a hard, brittle bottom is almost always due to uncirculated chemicals settling, poor water chemistry takes its toll but you almost always see it on the bottom first. I'm on year 13 with mine, hopefully I haven't jinxed myself this year.

 

[JasonLion]

Galvanization means adding a zinc coating on steel or iron. Zinc is considerably more corrosion resistant than either steel or iron, and so protects the iron/steel. However zinc is not corrosion proof. Extended contact with water will still result in corrosion eventually, just not any near as quickly as if it wasn't galvanized.

 

[AprilNC]

Galvanized steel is made to resist corrosion ... but that does not mean that it doesn't rust ... it just means that rusting takes longer. However, under certain conditions galvanized steel will rust just as fast as non-galvanized steel - one is when it is in contact with pressure treated lumber ... and another is when it is in contact with salt water.

 

[Shelley N]

Oh boy. Just cut off the liner and pulled the coving off and saw this nearly all around. I've always been BBB and have never added chemicals without the 1.5hp pump on for at least 30 minutes after. The difference between the sides and the bottom of the liner is dramatic. It turned into something else entirely.
View attachment 28620

 

[kpromero]

I am about to do another AGP since mine lasted 7 years with a SWG. Told that if i would have had an inline zinc anode i would not be purchasing another pool. Can someone care to elaborate if true or not.

 

[JasonLion]

There is nothing that will in one step save your pool from rusting. There are lots of things you can do, but none of them work every time. The best thing you can do is to be diligent about detecting, locating, and patching leaks. Getting a high quality pool made of good quality materials also helps a great deal. I've only seen sacrificial anodes make a significant difference when aluminum was involved.

 

[gwc]

Some newer pools that have resin components are rated for saltwater. They are priced higher than steel pools but you might not have to replace them as often. I installed one that was resin except for the wall and uprights.
I don't know for sure but could you replace yours with a 27' AG and use the same upright support pads and need minimal gradinging work?

 

[diyindux]

In response to the question about galvanized steel and rust, the zinc applied during galvanizing does oxidize. Zinc is actually more reactive than steel. The idea is that any corrosion loss will happen in the zinc layer first because it breaks down easier than the steel. It provides a physical barrier to protect the steel from exposure, but if there is a scratch then the corrosion will happen only at the exposed steel and won't progress under the adjacent zinc covered areas like it can with paint. On a pool, the zinc is pretty thin so it is easily damaged and you will see areas of rust like you have. However, it should take quite a while before it progresses to the point where the panel is too perforated to use anymore. In your case, there are rust converting and encapsulation products you can use on the rusted areas, plus you can apply zinc-rich coatings to add more cathodic protection.

 

[Shelley N]

Do you think I can save this? With flashing on the inside perhaps after sanding and painting the rust with the appropriate products?

 

[diyindux]

I didn't see any perforation of the steel in the pictures. Has it rusted through? If it has, I would not use any flashing. Flashing is aluminum and all you will do is create an electrolytic reaction between the dissimilar metals and accelerate the corrosion. If you want to use metal, get some galvanized steel and install it with rivets and then tape over the edges with duct tape to smooth it off some. The only problem is that you will see the outline of the patch. I'd use fiberglass after the rust has been repaired because it can be feathered out at the edges and blend into the wall a little better. You can lay enough cloth over the area to go well beyond the damage and then use foam on the walls to try and hide the repair. Once the liner is installed and the pool is full I think it should be fine for quite some time.

 

[woodyp]

I work in the steel industry and understand that zinc galvanizing is rated for 50 years use in the field. The coatings applied to structural steel would be thicker than the thin rails and posts used for pool construction. There is also a product called Spray Galv. which is used in the field for touch ups ow where the steel wasn't galvanized in the first place for erection purposes.

 

[Shelley N]

One or two spots are through, like in the second picture and two other places that are worse along the bottom edge. Fiberglass...cloth...feathering...I may need some official skilled help. I can just see myself after attempting this myself -- tape in my hair, securely attached, permenently, to the inside wall of the pool...upside down.

 

[Casey]

I can just see myself after attempting this myself -- tape in my hair, securely attached, permenently, to the inside wall of the pool...upside down.

LOL

 

[gwc]

Shelley got to have a picture of that.

 

[Shelley N]

I had no idea that we would ever need to replace the pool walls. Liner yes, walls no. My in-laws in Massachusetts 1978 AGP is still going strong and is about to get it's 3rd liner this summer. That's 18 years per liner for goodness sakes and not a hint of rust anywhere. Most of my issues are below the coving where the wet sand was against the wall. We've scraped, sprayed 2 coats of undercoating all around and will reinforce with galvanized steele where the integrity is gone and put the new liner in, but I'm not sure how many years I can trust the repairs. Maybe here in Colorado where the sun is so brutal we need to change liners out every 6 years or so just for safety sake.