Rust stain - appeared out of nowhere with small crack in plaster?

[TCardenas]

Hello everyone,

So I was brushing the pool this evening and had to rub my eyes. At first I thought it was some weird algae growth. Upon closer inspection, looks like rust. I ran my hand across it and towards the top (where the color is darkest), it sort of feels like a 'crack' - maybe an inch long. Not sure how long this had been there. We've been using the pool and brushing it regularly and I'm not sure how I could have overlooked this.

Pool is <4 years old. Here's a rough overview:

• 13,500 gal pool/spa
• shotcrete/plaster
• Pentair, cartridge filter, IC40, Globrite x4, Intelli-flo vari-speed pump, Rheem natural gas heater

Honestly I'm not even sure where to start here. I would greatly appreciate any advice/guidance you might have.

Best regards,
Tony

 

[Texas Splash]

I would be suspicious about the rebar support from behind the plaster. Try rubbing a Vitamin C tablet on the dark stained area. Also, if you have a magnet place it on the area to see if it sticks.

 

[TCardenas]

Edit - I tried a small rare earth magnet and couldn't get it to stick anywhere around that area.

 

[TCardenas]

I would be suspicious about the rebar support from behind the plaster. Try rubbing a Vitamin C tablet on the dark stained area. Also, if you have a magnet place it on the area to see if it sticks.

I tried a magnet, no luck unfortunately.

 

[Texas Splash]

I tried a magnet, no luck unfortunately.

Perhaps too deep for a regular magnet to grab. I'd be curious about the Vitamin C test. Sure seems like something is rusting and bleeding through.

 

[TCardenas]

Perhaps too deep for a regular magnet to grab. I'd be curious about the Vitamin C test. Sure seems like something is rusting and bleeding through.

I'll try the Vitamin C and report back. I'm sort of freaking out though - is this an indication of a major issue with the plaster or is it more something that can be 'spot treated' with some sort of seal/patch?

 

[Texas Splash]

I would think this is something your builder should be made aware of as I suspect you still have some warranty remaining (hopefully). If it is a break through the plaster and gunite, they'll ideally need to cut in there to find what metal is being exposed, remove it, then re-patch everything. Certainly something that is done quite a bit in the pool industry, but your builder should be involved.

Curious .... have you noticed any water loss or unexplained drops in chemical levels?

I'll tag @AQUA~HOLICS for a field expert opinion.

 

[TCardenas]

I would think this is something your builder should be made aware of as I suspect you still have some warranty remaining (hopefully). If it is a break through the plaster and gunite, they'll ideally need to cut in there to find what metal is being exposed, remove it, then re-patch everything. Certainly something that is done quite a bit in the pool industry, but your builder should be involved.

Curious .... have you noticed any water loss or unexplained drops in chemical levels?

I'll tag @AQUA~HOLICS for a field expert opinion.

I just sent him a text now We are scheduling the plaster folks to check it out. I was just about to comment - I haven't noticed any abnormal drainage from the pool or need to add water. I actually had the auto fill off for a good portion of the last few months and do keep an eye on the water level. Thanks again for all the feedback Texas Splash. Truly appreciate it.

 

[AQUA~HOLICS]

Possibly a pig tie exposure to water. This is the most common cause that I come across. Unfortunately it could be far away from the surface exposure, they travel through cracks to finally get to the surface. Plaster really has little to do with it unless it’s an impurity in the mix. Patching the plaster will not correct the problem, this is a metal exposure to water that needs to be removed. If it’s the steel cage it’s more involved to properly correct the situation.

 

[TCardenas]

Possibly a pig tie exposure to water. This is the most common cause that I come across. Unfortunately it could be far away from the surface exposure, they travel through cracks to finally get to the surface. Plaster really has little to do with it unless it’s an impurity in the mix. Patching the plaster will not correct the problem, this is a metal exposure to water that needs to be removed. If it’s the steel cage it’s more involved to properly correct the situation.

Thanks Aqua. I'm sort of preparing myself for the worst case. I'll definitely update the thread once I get a more clear answer from a pro.

 

[duraleigh]

While you are waiting, I would remove as much of the stain as possible with ascorbic acid or a crushed up slurry of vitamin C tabs,.

Don't let the stain continue to imbed itself.

Aqua Holics is probably right about the tie but it looks like it could also be coming from above that line. Clean it all up as best you can and then watch it closely to identify the exact location.

 

[AQUA~HOLICS]

Even the worse case scenario can be corrected so no future problems occur. Typically it’s a small area of exposure with a comparable surf patch.

 

[TCardenas]

While you are waiting, I would remove as much of the stain as possible with ascorbic acid or a crushed up slurry of vitamin C tabs,.

Don't let the stain continue to imbed itself.

Aqua Holics is probably right about the tie but it looks like it could also be coming from above that line. Clean it all up as best you can and then watch it closely to identify the exact location.

Thanks Duraleigh - I will work on that today. I appreciate the feedback.

 

[TCardenas]

While you are waiting, I would remove as much of the stain as possible with ascorbic acid or a crushed up slurry of vitamin C tabs,.

Don't let the stain continue to imbed itself.

Aqua Holics is probably right about the tie but it looks like it could also be coming from above that line. Clean it all up as best you can and then watch it closely to identify the exact location.

I built I guess what would be described as an unorthodox sort of 'dry dock.' I didn't want to shut down the pump and drain a ton of water so in the interim - this is working. I also have a better photo of the crack - it is approximately 3/4in and seems almost hairline.

Not sure if I'm doing the Vitamin C correctly - I crushed up tablets into powder and made a paste which I applied to the area. Any ideas how long to leave or just trial and error?

I'm still waiting on the plaster company to get back to me.

Appreciate the feedback as always,
Tony

 

[JoyfulNoise]

They’ll need to chip out the plaster in that spot and see what’s behind that crack. Could be a rebar tie, could be a nail that got caught up in the plaster or shotcrete, could the rebar support to that wall got too close to the surface, could be any number of issues. Once they address the source, they need to apply hydraulic cement to any of the shotcrete they chip out and then put a plaster patch on that spot. It’s not going to perfectly match the surrounding plaster so be prepared to live with a plaster patch in that spot until it all fades together.

 

[1poolman1]

Hello everyone,

So I was brushing the pool this evening and had to rub my eyes. At first I thought it was some weird algae growth. Upon closer inspection, looks like rust. I ran my hand across it and towards the top (where the color is darkest), it sort of feels like a 'crack' - maybe an inch long. Not sure how long this had been there. We've been using the pool and brushing it regularly and I'm not sure how I could have overlooked this.

Pool is <4 years old. Here's a rough overview:

• 13,500 gal pool/spa
• shotcrete/plaster
• Pentair, cartridge filter, IC40, Globrite x4, Intelli-flo vari-speed pump, Rheem natural gas heater

Honestly I'm not even sure where to start here. I would greatly appreciate any advice/guidance you might have.

Best regards,
Tony

That's a re-bar "bleed." Only sure cure is to cut that area of plaster out, re-seal or remove the rusted steel and re-plaster the area.

 

[TCardenas]

They’ll need to chip out the plaster in that spot and see what’s behind that crack. Could be a rebar tie, could be a nail that got caught up in the plaster or shotcrete, could the rebar support to that wall got too close to the surface, could be any number of issues. Once they address the source, they need to apply hydraulic cement to any of the shotcrete they chip out and then put a plaster patch on that spot. It’s not going to perfectly match the surrounding plaster so be prepared to live with a plaster patch in that spot until it all fades together.

Thanks Joyful - we are prepared for the color :-( In SoCA, any ideas on a rough ballpark on what cost we would be looking at for a repair like that?

 

[JoyfulNoise]

Thanks Joyful - we are prepared for the color :-( In SoCA, any ideas on a rough ballpark on what cost we would be looking at for a repair like that?

Sorry, regional prices prevail. No way I’d know. See what your plaster company says. It may fall under the warranty if it’s something embedded in the plaster. I know my neighbor had something similar happen but she pays for a weekly pool service and her service company did the job (it was a rusty scrap rebar tie that was caught up in the plaster). They just charged her for couple of hours of labor to do the fix, so a few hundred bucks. They only drained down a the pool about a foot below the crack which was unfortunately about midway down the deep end wall. So she had to drain off a lot of water and that definitely cost her a good chunk of money to refill.

Anyway, I’d see what your plaster guy says first.

 

[TCardenas]

Sorry, regional prices prevail. No way I’d know. See what your plaster company says. It may fall under the warranty if it’s something embedded in the plaster. I know my neighbor had something similar happen but she pays for a weekly pool service and her service company did the job (it was a rusty scrap rebar tie that was caught up in the plaster). They just charged her for couple of hours of labor to do the fix, so a few hundred bucks. They only drained down a the pool about a foot below the crack which was unfortunately about midway down the deep end wall. So she had to drain off a lot of water and that definitely cost her a good chunk of money to refill.

Anyway, I’d see what your plaster guy says first.

Thanks very much. On a positive note, the vitamin C slurry is working fantastic. I've been applying about every 2 hours (wiping off with damp sponge in between). Almost all the rust is gone!

I think I know the recommended answer but figured I would ask. Is there any DIY way to mitigate this small crack for a couple years or is something that absolutely should be cut out? Could one Dremel out a section and patch? I know I'm not under warranty anymore. Not that I don't want to pay for plaster company to do it, but if I'm going to be re-plastering the pool in a few years , could I seal this myself? With the setup I have right now I can keep the area dry for days. Or since it already started to rust, is it something that must be cut out?

Amazon.com

 

[JoyfulNoise]

You can’t “cover it up” or “seal it in”, the iron will continue to bleed out or around to the rest of the plaster. The source of the iron has to be figured out and that can only happen by chipping out the plaster in that area and exposing the gunite. It could be something simple like an inclusion in the plaster but it could also be much more if it’s coming from the shell. You could easily get into on your own only to be quickly out of your depth.

Maybe try calling around to some larger pool service companies as they will have people capable of doing the work and they’ll probably charge less than a professional plaster applicator.

You can certainly live with the “bleeding” if cleaning it up infrequently suits you. Then you can wait until you’re ready to renovate.