Recent Shotcrete application -- exposed rebar and other questions

[Eupelia]

Hi all,
I have absolutely loved reading so many interesting posts in the weeks leading up to our pool start. Thanks to you all, I found great industry guides and was in the pit manually digging a 3" clearance between rebar and our dirt walls and floor the night before Shotcrete was shot! There were areas where rebar was 1" from the dirt, and I'm too shy to ask a subcontractor to change something. Same for lapping bars touching instead of 2" spacing of laps. I also just learned from reading other posts that they shouldn't run piping laterally in a shotcrete surface and I know the sun shelf has two 3-foot pipes that are leading to the fountains and those pvc pipes were sitting right on top of the dirt and holding up the rebar. So I think I have enough support and it's so shallow there that I'm fine with it.

The Shotcrete was applied Wednesday and there are a couple of issues/questions.

I have a line of three 3-5" holes running across a wall where I see exposed rebar (which I know will be patched later) but my concern is that I can clearly see gaps traveling behind the surface of the concrete if I look to the left and right inside the holes. I removed some of the popcorn pieces covering parts of the holes to have clear access for a fill and to see the issue. To me it looks like they didn't get Shotcrete around that entire piece of rebar, or like it started to fall off and wasn't pushed back in (the concrete near or covering parts of the hole looked like popcorn with gaps all around leading into the holes).

The only thing I know about the Shotcrete is that they used a "higher psi mix" and they definitely used rebound somewhere but I don't know where. Nothing was hauled out, but it's too late to do anything about that so I'm focusing on the obvious issues. It took about 3 hours, truck had to go back for a refill, folks started troweling during the break. No one has watered the concrete but it rained once and, now that I know that matters,I'll be doing it every day.

We are in Florida and we have sandy or sand dirt, if that matters.


The second issue is that the paper form collapsed in due to some dirt pressure so I have two places where the wall is about 3" thick by my estimates at about 12" water depth. The wall is supposed to be about 7.5" thick at the beam and the paper collapsed in 3" or 4" in these two areas. I don't think they planned on doing anything about it until I brought it up and they said 3" thickness is plenty ("we demo pools from 30 years ago with 1" thick walls") but they could pour some concrete behind it if I want. I don't even know if that's ok to do on top of the "chicken wire paper", or whether we would have to remove the paper and add concrete in which case what is the disadvantage of having removed that continuous paper with the chicken wire mesh in it, etc. I'm not even sure what that paper is for

The corner wall is also a bit narrow but almost no water pressure at that height so the narrower corner up high is ok with me. I'm only wondering if our 12x24 coping will be fine at that corner near the spa where the beam is about 5".

I would love to know the proper fix for the holes in light of the continuous gaps I see behind the wall surface, as well as the best way to build up the thin wall areas (if it's even necessary at that depth of water) so I can request the right fix and explain my reasoning. Best-case and OK-case scenarios of what you would want are all appreciated.

I included pics of the issues (the vertical PVC is just square to show where the beam lip is in comparison to dirt below because it's too hard to capture depth with a camera) and then I'll post some other pics of the project in a reply below in case anyone's curious. I love seeing everybody's project pictures.

Thank you all and Happy Easter!

 

[kimkats]

Hi and welcome to TFP. SO sorry to be meeting in this way

I am going to call in a couple of others manly for the #1 & 2 spots where the paper/wire went in. I know what my gut says but want the people who do this for a living to have input. @jimmythegreek @ajw22

For the holes they can and should put hydraulic cement in those. They will have to do it by hand and push some in to fill up those areas. I would SO be standing behind them watching over their shoulders to make sure it is done correctly.

What is your decking going to be? That could also impact what they do with the dipped in places.

 

[Eupelia]

What is your decking going to be? That could also impact what they do with the dipped in places.

Hi! Thanks so much for responding, I won't mind standing right behind them when they fill it. I'm super polite and apologetic when I do it so hopefully they understand. If not, I already stuck my nose in by chipping away at some of the poorly connected cement at the openings and they already won't like me for making the hole a little bigger. No love lost

Our decking is Shellstone paver 16x24.

 

[Eupelia]

Oh and here are other random pictures just for those who like this stuff. I LOVE the dirt layers. Nearest the bottom was a golden layer of the softest finest sand I'd ever felt (we must have been under the ocean at some point!) followed by this dark caramelized organic matter line then a large layer of silver sand followed by a layer of ashy gray sand that looked like it was from a volcano eruption or something!

 

[ajw22]

Do you have pics with the rebar fully in place before gunite?

 

[kimkats]

Love the dirt layers as well. Sure does tell a story about how the land was and is!

I'm super polite and apologetic when I do it so hopefully they understand.

I have been knows to have a cooler full of water and some yummies to hand out to soften the "bonus" of my breathing down their necks asking questions Yeah I do have control issues LOL

they already won't like me for making the hole a little bigger.

Here is betting they will NOT even notice what you did. I would just point at it and NOT say a word and see what THEY say. Get EVERYTHING in writing!!!

paver 16x24.

So with pavers it is REALLY going to be important for the shell and such to be just right to keep everything level!

 

[Eupelia]

I think my husband does, let me check. but I remember it in detail because I spent two days digging a 3" clearance around it! The stairs were just a 60 degree angle drop, no stair shapes so that is pure concrete. The mason lapped the rebar and tied the overlapping pieces together, there was no gap. Each row was about 1 ft apart, ending about 2"-3" below the beam wood form in an L shape. It was only supported off the dirt by about 6-8 chunks of cinderblock. Let me check my hubby's phone!

Do you have pics with the rebar fully in place before gunite?

 

[AQUA~HOLICS]

Issue # 1: prior to patching with hydraulic cement the area around the exposed rebar needs to have all loose material remove. This will more than likely leave a large crater around the rebar to be patched and that’s what you want to give the hydraulic cement a good bonding surface.

Issue # 2: if concrete was to be poured behind the bond beam to bring out the width it would not adhere to the Shotcrete and not add to the strength of the shell. Wire paper needs to be removed and exposed Shotcrete to be properly cleaned and prepared for pneumatically applied concrete.
Thickness of the walls are determined by engineers and are typically requirement’s that need to be met at a minimum.

 

[Eupelia]

Do you have pics with the rebar fully in place before gunite?

This is what we have, mid progress.

 

[ajw22]

This is what we have, mid progress.

I wanted to get an idea of how much rebar you had.

I picked this pic from an Under Construction thread and it looks like it has more rebar closer spaced then your pool. And also note the spacing and thickness of the rebar along the walls.

Now the amount of rebar needed varies with soil conditions and your building in sand will put less pressure on the pool walls then expansive soils in other areas.

Issue # 1: prior to patching with hydraulic cement the area around the exposed rebar needs to have all loose material remove. This will more than likely leave a large crater around the rebar to be patched and that’s what you want to give the hydraulic cement a good bonding surface.

Agreed

Issue # 2: if concrete was to be poured behind the bond beam to bring out the width it would not adhere to the Shotcrete and not add to the strength of the shell. Wire paper needs to be removed and exposed Shotcrete to be properly cleaned and prepared for pneumatically applied concrete.
Thickness of the walls are determined by engineers and are typically requirement’s that need to be met at a minimum.

This is basically what I was going to say.

You got a sloppy and below average gunite job. And I am not sure I am impressed with your rebar pics but don't have a view of the final work there.

Simply building a concrete wall alongside the gunite wall to add thickness does not add any structural support to the gunite shell. To add to the structural support will require rebar to be epoxied into the gunite wall and rebar framed for the new thickness so that you have the rebar tieing together the two walls into one structure and they both have rebar in them. Pouring concrete for thickness without rebar will accomplish little.

Now is that really necessary? You are built in sandy soil which will put little pressure on the shell.

Did your pool build have engineering drawings with an engineers stamp on it? Such a drawing should have the minimum rebar and gunite specifications for your pool. If what was built does not meet the engineering drawing you should consult with the engineer who stamped them for what the remediation is.

 

[Eupelia]

I have been knows to have a cooler full of water and some yummies to hand out to soften the "bonus" of my breathing down their necks asking questions Yeah I do have control issues LOL

Great idea! Who can dislike someone who is handing out sandwiches and Dunkin’ Donuts?! I completely feel you on the control issues. Each time additional work is done, my husband just sighs and says “how long you gonna be out there tonight?”

So with pavers it is REALLY going to be important for the shell and such to be just right to keep everything level!

are there any resources you like about beam requirements based on coping characteristics?

 

[Eupelia]

Issue # 2: if concrete was to be poured behind the bond beam to bring out the width it would not adhere to the Shotcrete and not add to the strength of the shell. Wire paper needs to be removed and exposed Shotcrete to be properly cleaned and prepared for pneumatically applied concrete.

Simply building a concrete wall alongside the gunite wall to add thickness does not add any structural support to the gunite shell.

darn, they’re not going to want to bring back the gunite guys for sure...OR drill and epoxy rebar. And the forms guy is blaming the shooter and the shooters are blaming the forms guy. Since It’s only about a 4” fill, is there anyway to put pneumatic cement with rebar in the fill area but just somehow glue the two cement surfaces together?

And I don’t have any engineering reports or plans, I didn’t even know that was a thing for pools. Seems obvious now! our pool is tiny so it may be misleading, it is only 12 feet wide and there was one bar every foot in a little grid. Definitely only one line of rebar framing the beam unlike that pro job photo you posted. That was immaculate! My guys poured over dozens of extra steel ties and a DumDum wrapper they just threw in the sand bottom.

sonwhat is that paper for anyway? so curious.

 

[ajw22]

Pneumatically applied concrete is gunite or shotcrete.

No, you can’t glue concrete walls together.

 

[kimkats]

are there any resources you like about beam requirements based on coping characteristics?

I am going to ask @ajw22 take this one. I am in way over my head on this area.

 

[jimmythegreek]

The bond beam is part of the engineering of the pool shell and the coping doesn't affect it. Only time it does is if extra large or custom coping is used and the concrete is widened to accommodate.....more width is non-issue. Depending on your jurisdiction most pools need engineering and a PE stamp. Ask for it and reach out to who stamped the shell. If PB is the designer your at their mercy

 

[AQUA~HOLICS]

In my area you cannot pull a permit without submitting a steel engineering plan wet signed by the engineer. The rebar company will then fallow the plans as it dictates how many bars, size of steel and how tight the crossovers are. This is a picture of a #100 plan that every pool is required to have at minimum. Depending on soil and slope of yard you would be required to have extra plans that dictate even more requirements of the steel cage.

 

[Eupelia]

So our sunshield is supposed to be 8-9" of water. I just went and measured and the raw concrete of the sunshelf is 9" from the lip of the beam. We still have to apply the plaster or whatever it is that goes over the concrete. I don't know how thick the plaster/waterproofing and pebbletec layer is supposed to be. And it looks to me like most pool water levels are usually about 4" down from the bottom of the coping, right? So right now, without accounting for whatever goes over the concrete, we would have 5" of water when the pool is filled to the right level. Am I right on this estimate?

Additionally, the 3 steps are 10", 10" and 11" in height. The 11" one is like doing a box jump at the gym

So I'm not sure what happened but I brought it up to my PB today and he said not to worry about it, that they can add cement to the top of the beam. I said "Four inches of cement?" He said "no, we would add about 2.5" including the travertine thickness and that now makes the water depth between 7-9" depending on how full you run the pool." Do those calculations sound right? how thick is the layer of plaster and pebbletec supposed to be?

And, if they add 1.5" of concrete to the top of the beam, how will that adhere? Will that be stable? From what i can tell at the filter basket cut out, there is currently about 3-4" of cement above teh top of the rebar supporting the beam. And won't the filter hole thing be really low, the hole is already about 10" down from the lip, i'm not sure what the norm is. The step down onto the sunshelf would be 11" he said and the steps would stay the heights they are.

I also have to check if that would work for the travertine because the pool travertine has to line up with the travertine they will lay on top of an existing cement pad for the porch 6 feet away.

Any thoughts I can share when i meet with them to look at the height would be appreciated!

 

[TampaKathy]

So our sunshield is supposed to be 8-9" of water. I just went and measured and the raw concrete of the sunshelf is 9" from the lip of the beam. We still have to apply the plaster or whatever it is that goes over the concrete. I don't know how thick the plaster/waterproofing and pebbletec layer is supposed to be. And it looks to me like most pool water levels are usually about 4" down from the bottom of the coping, right? So right now, without accounting for whatever goes over the concrete, we would have 5" of water when the pool is filled to the right level. Am I right on this estimate?

Additionally, the 3 steps are 10", 10" and 11" in height. The 11" one is like doing a box jump at the gym

So I'm not sure what happened but I brought it up to my PB today and he said not to worry about it, that they can add cement to the top of the beam. I said "Four inches of cement?" He said "no, we would add about 2.5" including the travertine thickness and that now makes the water depth between 7-9" depending on how full you run the pool." Do those calculations sound right? how thick is the layer of plaster and pebbletec supposed to be?

And, if they add 1.5" of concrete to the top of the beam, how will that adhere? Will that be stable? From what i can tell at the filter basket cut out, there is currently about 3-4" of cement above teh top of the rebar supporting the beam. And won't the filter hole thing be really low, the hole is already about 10" down from the lip, i'm not sure what the norm is. The step down onto the sunshelf would be 11" he said and the steps would stay the heights they are.

I also have to check if that would work for the travertine because the pool travertine has to line up with the travertine they will lay on top of an existing cement pad for the porch 6 feet away.

Any thoughts I can share when i meet with them to look at the height would be appreciated!

Plaster should be 1/2 inch thick, the waterline will be about 3 inches down from the bottom of the coping. I agree that adding concrete is probably going to mess up the slope of the travertine. Is the 11 inch step the last one going into the pool?

 

[TampaKathy]

Also, keep all your build questions in one thread...it helps people to be able to go back and see what's already been talked about...you can change the title of your post each time if you want. A mod will probably move this one.

 

[tommelton]

Also - adding additional concrete at the top of the bond beam will increase the distance from coping to the first step.