Patching Shotcrete

PSPOOL

Bronze Supporter
Oct 5, 2021
26
So.Cal.
Plumber didn't realize the Baja Shelf return had a step and cut the pipe too short. This wasn't noticed until well into the Shotcrete process. The area of the step containing the return had to be chipped out and the pipe extended. The plumber patched the area with Spec Mix and a bonding agent (concrete glue). What's the longevity of this type of patch? I was under the impression that only hydraulic cement was to be used in shell patching.
 
I guess it depends on what Specmix product the plumber used … was it a mortar mix or shotcrete mix product? Did you get a look at the bag he got the material from?
 
Thanks for responding. The bags were labeled "Spec Mix". It was the same material he was using to assemble and grout block walls. He just added a liquid bonder to the mix.
 
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Well, that’s not great. You really want to use a hydraulic cement for filling and patching work. If the area isn’t very big, the specmix might hold for a very long time without issue as the plaster surface is really the waterproofing layer. A small patch has no effect on the overall integrity of the shell so it’s really up to you if you want to make a big deal about it with the PB.

Sucks, but this happens a lot. Sometimes these guys just use whatever is sitting on their trucks rather than going the extra step to get the job done right.
 
I’ll agree with Allen but only partially … I think the patch will work for now but I suspect that in long years out it’s going to crack at the interface. The problems is, as best I can tell, is that the pipe isn’t tied to the rebar frame. So you have a pipe buried into low compressive strength specmix … eventually the repetitive stress caused by that return running is likely going to cause some part of that cement joint to shear. But who knows when that might happen … year one, year 5, year 30 🤷‍♂️ simply no way to know. I would just document it with the PB and ask if the warranty can be amended to include that patch as a potential area of concern since it was created after the shell was formed and an improper cement material was used to fill it. The PB may say no but it doesn’t hurt to ask.
 
I’ll agree with Allen but only partially … I think the patch will work for now but I suspect that in long years out it’s going to crack at the interface. The problems is, as best I can tell, is that the pipe isn’t tied to the rebar frame. So you have a pipe buried into low compressive strength specmix … eventually the repetitive stress caused by that return running is likely going to cause some part of that cement joint to shear. But who knows when that might happen … year one, year 5, year 30 🤷‍♂️ simply no way to know. I would just document it with the PB and ask if the warranty can be amended to include that patch as a potential area of concern since it was created after the shell was formed and an improper cement material was used to fill it. The PB may say no but it doesn’t hurt to ask.
It will likely last until the pool needs to be replastered. Then, if necessary, the area can be patched again.

A can of worms will be opened if you try and change the materials now.
 
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Here's the pipe prior to Shotcrete.View attachment 623047

That picture shows the pipe anchored to the rebar. The other pic isn’t as clear.

Either way, there’s really nothing you can do about it at this point without making a huge fuss and potentially making the situation worse. Just leave it as-is and make note of it in your records. The PB holds the warranty on the shell through the gunite company. If something happens on that area right away, then you have more than enough photographic evidence to show that it’s not your fault in any way.
 
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