Exposed Rebar Post Plaster Chipping

[BlueLagoon]

Hi everyone, I am new here. Looking for some insight. My pool contractor is being very cautious in how he advises, as they do not want any liability for future repairs. I have a gunite pool from the '60s in Southern California. Upon chipping out the old plaster, which I have no record of how old or how many times, if ever, it has been done before, there are a few areas that have exposed rebar.

Is there a safe and proper way to seal these areas to avoid future rust stains and problems down the line?

Let me know any questions or if you need pictures! Thanks!!!!

 

[Bperry]

Hi everyone, I am new here. Looking for some insight. My pool contractor is being very cautious in how he advises, as they do not want any liability for future repairs. I have a gunite pool from the '60s in Southern California. Upon chipping out the old plaster, which I have no record of how old or how many times, if ever, it has been done before, there are a few areas that have exposed rebar.

Is there a safe and proper way to seal these areas to avoid future rust stains and problems down the line?

Let me know any questions or if you need pictures! Thanks!!!!

Hydraulic cement if theres room available to get the correct thickness. If the rebar will be close to the finished surface( it shouldn’t be) then it can be cut out.

 

[BlueLagoon]

@Bperry Thank you for the quick response! It seems like some areas are worse than others and some have more room than others to add a layer of some Hydraulic cement. Take a look at these pictures and let me know what you think. From my research, it seems like the pool contractor went a little heavy with the chipping tools. Of course, when I talk to him, he says he's done 1,000s pools this same way, and this rebar is the fault of the original construction, so he takes no responsibility. Shocker.

By the way, the picture with the lizard was the old copper pipe return we abandoned. We need to patch this up of course.

EDIT: Adding that this pool has been chipped for about 2 years. Unfortunately, we had an issue with a major grading permit that took a very long time to resolve. The pool renovation was shutdown until that permit was issued. The rebar has been exposed to the elements all this time of course.

 

[Bperry]

@Bperry Thank you for the quick response! It seems like some areas are worse than others and some have more room than others to add a layer of some Hydraulic cement. Take a look at these pictures and let me know what you think. From my research, it seems like the pool contractor went a little heavy with the chipping tools. Of course, when I talk to him, he says he's done 1,000s pools this same way, and this rebar is the fault of the original construction, so he takes no responsibility. Shocker.

By the way, the picture with the lizard was the old copper pipe return we abandoned. We need to patch this up of course.

EDIT: Adding that this pool has been chipped for about 2 years. Unfortunately, we had an issue with a major grading permit that took a very long time to resolve. The pool renovation was shutdown until that permit was issued. The rebar has been exposed to the elements all this time of course.

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Hard to tell how thick the original gunite was in some of those spots cause theres still some plaster spots around it. It does seem like a bit aggressive but the rebar does kinda look closer to the surface than expected. Any of the holes or big cavities with rebar can be easily patched, its the large surface areas of exposed rebar I dont know best way to repair but I do know they need to be covered before plaster.

 

[mbdesa]

The PB needs to brown coat that pool with at least 2, but preferably 3" of shotcrete.

 

[sktn77a]

If you just plaster over that, you'll have rust stains coming through in a couple of years. Agree with the above comment, the exposed rebar needs to be covered/sealed before plaster is applied.

 

[BlueLagoon]

Hard to tell how thick the original gunite was in some of those spots cause theres still some plaster spots around it. It does seem like a bit aggressive but the rebar does kinda look closer to the surface than expected. Any of the holes or big cavities with rebar can be easily patched, its the large surface areas of exposed rebar I dont know best way to repair but I do know they need to be covered before plaster.

Yes, I agree. We need to repair these rebar pieces.

The PB needs to brown coat that pool with at least 2, but preferably 3" of shotcrete.

The PB more or less said the same thing. The problem is that we already redid the waterline tile and coping. It's also not financially preferable to pay them to add the shotcrete if there is a more practical solution. Looking for thoughts.

If you just plaster over that, you'll have rust stains coming through in a couple of years. Agree with the above comment, the exposed rebar needs to be covered/sealed before plaster is applied.

Yes, I agree. That is the plan.

The PB has suggested that we spot treat the visible rebar with an epoxy paint and then use this product: DRYLOK 1 gal. White Acrylic Interior/Exterior Wet Wall Bonding Primer for Concrete and Masonry 25513 - The Home Depot - to coat the entire pool. His concern is that there could be additional places where rebar is just barley under the surface.

Has anyone had an experience like this where they used a waterproof product to seal the shell? My concern is that it could affect the bonding of the plaster. It is a long story, but my PB is not offering any guarantee whatsoever. It's crazy, but I paid him over two years ago to do the plaster and we ended up delayed by the city for some unrelated permits. I kept thinking the end of that was near, but it took two years.

Thanks everyone!

 

[BlueLagoon]

Anyone have experience with this Drylok product or something similar to waterproof the shell to hedge against future rebar rust?

 

[Bperry]

Anyone have experience with this Drylok product or something similar to waterproof the shell to hedge against future rebar rust?

You are in uncharted territory. The whole point of the rebar is to stabilized the cement structure and if thr rebar is exposed, it cant do its job. It also means your shell is thinner than it was designed to be and so more likely to crack once water gets back in. Its your money but the best fix is putting back the missing gunite otherwise you spent all that money just to risk ruining all the work that was done.

The guy that overchipped it really wont recognize that?

 

[BlueLagoon]

You are in uncharted territory. The whole point of the rebar is to stabilized the cement structure and if thr rebar is exposed, it cant do its job. It also means your shell is thinner than it was designed to be and so more likely to crack once water gets back in. Its your money but the best fix is putting back the missing gunite otherwise you spent all that money just to risk ruining all the work that was done.

The guy that overchipped it really wont recognize that?

No. He claims he's chipped thousands of pools the same way. Never had an issue. He's saying my pool construction is faulty. The pool was built in the 60s. I don't know the history, but I'm sure it's been replastered a few times since then. But prior to this there was no cracking or staining.

He never mentioned concerns with cracking. He's biggest thing is he doesn't want to warranty rust stains. That's what he's hung up on which is why he's suggesting to spot treat the rebar and use that Drylok material to seal the shell.

 

[Bperry]

No. He claims he's chipped thousands of pools the same way. Never had an issue. He's saying my pool construction is faulty. The pool was built in the 60s. I don't know the history, but I'm sure it's been replastered a few times since then. But prior to this there was no cracking or staining.

He never mentioned concerns with cracking. He's biggest thing is he doesn't want to warranty rust stains. That's what he's hung up on which is why he's suggesting to spot treat the rebar and use that Drylok material to seal the shell.

Using the drylock thing is probably ok as long as they put back 2-3” of cement over the rebar. Theres really two different issues going on at once. Maybe its not his fault that the shell has been chipped too thin, maybe it is. I just dont get the hesitancy to fix the parts that are too thin.

 

[BlueLagoon]

Using the drylock thing is probably ok as long as they put back 2-3” of cement over the rebar. Theres really two different issues going on at once. Maybe its not his fault that the shell has been chipped too thin, maybe it is. I just dont get the hesitancy to fix the parts that are too thin.

Yes, he said they normally paint the rebar. I think the more appropriate thing is to paint and cover with some hydraulic cement as you mentioned. So one way or another I'll be doing that for sure.

I'm wondering if Drylok is the best thing though. It seems like a generic product from home Depot. I'm wondering if there is a pool specific product alternative that I should be using to seal the shell.

Thank you for your input on this!

 

[wireform]

Before using drylok I'd call them and see what their take is using it altogether in a pool situation with plaster on top of it.

 

[HermanTX]

Using the drylock thing is probably ok as long as they put back 2-3” of cement over the rebar. Theres really two different issues going on at once. Maybe its not his fault that the shell has been chipped too thin, maybe it is. I just dont get the hesitancy to fix the parts that are too thin.

IMO - the shell integrity is paramount. Maybe @AQUA~HOLICS has some views on this.

 

[AQUA~HOLICS]

It seems that the concern is all about not having the cage rust to the surface, in my opinion the integrity of the shell is the most critical.
Core samples to inform you of the thickness then you can formulate a plan.
The rebar cage needs a minimum of 3” of coverage (7” that includes the thickness of the bar).
All steel engineering firms I work with would require that in order to pass inspection.

From the pictures provided it difficult to determine if the Shotcrete was chipped out to a depth of 3” that exposed the cage or that the cage was originally shot thin, either way, having a Shotcrete crew add the proper thickness to maintain its integrity should be at the top of the list.

 

[BlueLagoon]

It seems that the concern is all about not having the cage rust to the surface, in my opinion the integrity of the shell is the most critical.
Core samples to inform you of the thickness then you can formulate a plan.
The rebar cage needs a minimum of 3” of coverage (7” that includes the thickness of the bar).
All steel engineering firms I work with would require that in order to pass inspection.

From the pictures provided it difficult to determine if the Shotcrete was chipped out to a depth of 3” that exposed the cage or that the cage was originally shot thin, either way, having a Shotcrete crew add the proper thickness to maintain its integrity should be at the top of the list.

I can appreciate that. I'm also in Southern California. This pool has been here since the 1960s. There's been no past evidence or current evidence that the shell has been compromised. Is that a worthy consideration that shell integrity is intact? We just have a few places in particular where the chipping was what seems to be excessive.

I've already replaced all the coping and waterline file. If I was to add additional gunite wouldn't it require replacement of those in order for the transition of the shell to be flat with the tile?

 

[Bperry]

There's been no past evidence or current evidence that the shell has been compromised. Is that a worthy consideration that shell integrity is intact?

The evidence is the rebar being exposed. Core samples is a good idea IMO.

They should be able to blend whatever patchwork they do with the tile.

 

[HermanTX]

Is that a worthy consideration that shell integrity is intact? We just have a few places in particular where the chipping was what seems to be excessive.

That may have been true before the chipout started but now that may not be the case.
In a new pool shell has 1" diameter rebar lifted off the ground or away from the side such that 3 inches of gunite goes below the rebar and then 3 inches applied above it to create the 7 inches of total thickness referred above.
Based on the pictures some areas do not have 3 inches of gunite above the rebar so that affects the integrity of the shell.

A core would be drilled to determine the actual thickness of the total shell at any given point. Then a decision can be made if you wish to add additional gunite or take the risk just to cover it marginally to prevent rust bleed through to the plaster.