Bond beam repair

Davileet

Well-known member
Mar 28, 2020
69
Gainesville, VA
I recently purchased a house with an in ground pool where the tile was loose around 1/3 of the pool, and a lot of the coping sounded hollow. After removing all of the tile I discovered bond beam damage in several places. As such, I have removed the coping stones, and chiseled out the bond beam until no more hollow sounds exist.

Original installation of the coping caused the mortar below to go flush against the deck which I assume caused the beam failures. I have chipped out that old mortar and cleared out behind the bond beam to give it the correct space to move. Unfortunately about 25% or more of the deck has 2-3" of empty cavity. Pool deck has no cracks and is in overall good condition except being hollow underneath. Does anyone have suggestions of how to fill this gap safely without pressing on the backside of the pool?

Couple more questions: at which point does the bond beam repair need rebar placed in to help hold the cold joint? I have attached pictures. Also, in places where the plaster has been chipped out below the tile line to remove loose material, I am assuming I will not need to repair the bond beam below the original tile line since the pool is getting re-plastered?

Thank you

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ajw22

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TFP Guide
Jul 21, 2013
16,046
Northern NJ
I think what you are describing is loss of the expansion joint that allowed the movement of the deck to crack the bond beam. I often warn about maintaining the expansion joint and you show one of the most severe damage I have seen.


The expansion joint should be filled with foam backing rod and Deck-O-Seal.




I think you have to drill holes in the bond beam and epoxy rebar in and then build up cement around it. @bdavis466 likely has thoughts.
 

bdavis466

TFP Expert
Platinum Supporter
Aug 4, 2014
5,411
San Clemente, CA
It's hard to tell from the pictures but it doesn't look like you have enough concrete deck around the pool to apply the kind of force that would be needed to crack the bond beam. My guess is that when the gunite was shot the trimmings were used to build up the top edge of the beam which is why you're seeing the solid areas below what you chipped out.

Was that top Edge able to be taken off in solid chunks several inches to feet long or was it just a crumbled mess of rubble and sand?

Alan is correct, epoxy rebar in place and use a high-strength concrete mix with a bonding agent on top of a very clean and well prepared shell.

Just because the pool is getting replastered doesn't mean that those areas below the tile line can be left as-is. The plaster is just a cosmetic semi waterproof surface. It's only as good as the structural surface its adhered to.
 

Davileet

Well-known member
Mar 28, 2020
69
Gainesville, VA
@bdavis466 and rest, thank you all for the responses. I assumed the information you have provided would be the case. Is there instances where the bond beam has only been chipped away an inch or two and it does not need rebar? Or should I try and put support for all instances where the bond beam was taken below its original height?

The top edge of the bond beam where damage could be seen before coping was removed came off in big chunks, attached to coping and sometimes not. The worst part of the beam was a crumbled mess of ruble and sand, and the other hollow sounding part came up in chunks. I have attached a picture of the pool with the type of rubble removed.

I have also attached pictures of the mortar that I feel was pinched between the deck and bond beam, and the end result of cleaning it out and giving it space. I will be using tall foam expansion from earth to top of deck when pouring new bond beam. Any recommendations for flexible concrete forms to help in rebuilding the bond beam?

So the part under the tile line that is only missing the plaster, but otherwise good concrete underneath, should that be filled when doing the bond beam repair?

Pictures linked were too large to upload.

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Cleanup 1
clean up 2
clean up 3
 
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bdavis466

TFP Expert
Platinum Supporter
Aug 4, 2014
5,411
San Clemente, CA
No need to add rebar if the repair is less than 4" thick.

Use 1/4" plywood for the coping forms. If you're not a concrete guy then you'd be better off with a precast coping. Finishing that much coping as a DIY project is no easy task... especially if anticipating satisfactory results.

I don't understand your question about the plaster. The old plaster should all be removed prior to replastering. Any cracks in the shell need to get addressed.
 

Davileet

Well-known member
Mar 28, 2020
69
Gainesville, VA
Thank you for the information on adding rebar to the bond beam. I am assuming that if I used the correct bonding slurry that the bond beam repair and the mortar joint isn’t going to cause fracture issues in the future?
I will use 1/4” plywood if it will bend correctly. Thank you for that information. I have already ordered the precast coping, it should be here in a week or so.
It is unfortunate you mention all plaster should be coming out. I had probably six quotes done and not one of them wanted to chip out whole pool. They want to do chip out around fittings and under tile, acid wash, and Bond Kote, then new plaster on top of old.
I have smacked around the walls and there is little to no hollow spots below the tile line.
 

bdavis466

TFP Expert
Platinum Supporter
Aug 4, 2014
5,411
San Clemente, CA
Thank you for the information on adding rebar to the bond beam. I am assuming that if I used the correct bonding slurry that the bond beam repair and the mortar joint isn’t going to cause fracture issues in the future?
I will use 1/4” plywood if it will bend correctly. Thank you for that information. I have already ordered the precast coping, it should be here in a week or so.
It is unfortunate you mention all plaster should be coming out. I had probably six quotes done and not one of them wanted to chip out whole pool. They want to do chip out around fittings and under tile, acid wash, and Bond Kote, then new plaster on top of old.
I have smacked around the walls and there is little to no hollow spots below the tile line.
If that's the case then the plaster can stay. The new plaster can fill any voids left from the repairs you're making.

I thought the forms were for poured concrete coping. The concrete mix you make for the bond beam should have high cement/low water content and can be applied without forms. Slap it on about an inch thick and work it into the crevices around the beam. Once you get back to where you started you can put several inches on, let it set up for a little while and then trim it to the height and contour of the shell.

If you'd rather use forms and a pourable mix, use 1/8" luan for the tight bends and a plasticizer in the mix to keep the water content low while keeping it pourable.
 

Davileet

Well-known member
Mar 28, 2020
69
Gainesville, VA
I was thinking since the damage to the bond beam was somewhat extensive in some places I would need a form to rebuild and pour. I will do what you said and make it thicker instead of a thinner mix. You still suggest doing a thicker mix without forms for building up about six inches with new rebar added then? Is there a good cement product your recommend for the bond beam?

Also, any product recommendations for the coping mortar, tile thin set, and grout?

Lastly, once I build the bond beam back up, should I put a water proof coat on it? Something like Hydro Ban?

I really appreciate your time and input. It has been hard finding the exact information I need.
 

Davileet

Well-known member
Mar 28, 2020
69
Gainesville, VA
I think what you are describing is loss of the expansion joint that allowed the movement of the deck to crack the bond beam. I often warn about maintaining the expansion joint and you show one of the most severe damage I have seen.


The expansion joint should be filled with foam backing rod and Deck-O-Seal.




I think you have to drill holes in the bond beam and epoxy rebar in and then build up cement around it. @bdavis466 likely has thoughts.
Thank you for this information. I will use the Deck-O-Seal product for behind the coping.
 

bdavis466

TFP Expert
Platinum Supporter
Aug 4, 2014
5,411
San Clemente, CA
I was thinking since the damage to the bond beam was somewhat extensive in some places I would need a form to rebuild and pour. I will do what you said and make it thicker instead of a thinner mix. You still suggest doing a thicker mix without forms for building up about six inches with new rebar added then? Is there a good cement product your recommend for the bond beam?
6" is no problem, especially if there's rebar there to support it. You might have to do it in a couple passes though. I would make my own mix of Plastic cement and sand - 50:50 mix. It will be sticky so apply it in a manner so that you can shave off material, not necessarily trowel it into place.


Also, any product recommendations for the coping mortar, tile thin set, and grout?
Laticrete 254 thinset and Laticrete epoxy grout

Lastly, once I build the bond beam back up, should I put a water proof coat on it? Something like Hydro Ban?

I really appreciate your time and input. It has been hard finding the exact information I need.
Absolutely, HydroBan is a good product. Merlex Super Blokade is also a very good choice and should be very easy to get a hold of. I believe it can still be ordered through Home Depot.


 
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jimmythegreek

TFP Expert
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In The Industry
Aug 10, 2017
2,134
Morris Cnty NJ
Late to the thread but I agree with Bdavis. If you go standard high strength route find plasticizer and mix as dry as possible and build it up. I also dont think that deck put enough force on the bond beam to damage it. Probably a compound issue of slop thrown on at the end and poor craftsmanship. For a DiY it might be easier to use cement nails and form it. Do not skimp on bonding agent and prep, clean all dust really good. Laticrete 254 is all I use on coping all there product lines are good. Any spots in pool should be chipped out to investigate its safer to just chip it all out on a problem pool. Nothing worst than spending big money for a Reno and having an issue sooner than later. The extra money hurts now but it's a cheap insurance policy really
 

Davileet

Well-known member
Mar 28, 2020
69
Gainesville, VA
Thank you both for those replies. Great information there. I feel I have just about all the questions answered before getting to serious work!

I did a bucket leak check for about a week, and things seemed fine. This was with the water line below the tile, so I would like to think the current older plaster is not leaking. I have smacked the plaster surface in a lot of the pool, maybe 70%, and have found very little to no hollow sounds. It is unfortunate that plaster crews in northern VA charge such high prices and do a sub par job of not removing all older plaster. I have seen a lot of videos on youtube where all plaster is hammered or water blasted off, wonder why the status quo is different here.

To prep the damaged bond beam, do I pressure wash, acid wash, add bonding agent, and then add the concrete?
Should I put anything on the new and old rebar to waterproof it before covering in concrete?
Any particular bonding agent that is recommended?

With the 50/50 plastic cement mix, is that for both bond beam repair and coping mortar? Do you recommend adding thin set to bottom of coping as well?

Thanks again guys.

Edit. Should I chip out the whole pool while I am at it?
 

bdavis466

TFP Expert
Platinum Supporter
Aug 4, 2014
5,411
San Clemente, CA
Thank you both for those replies. Great information there. I feel I have just about all the questions answered before getting to serious work!

I did a bucket leak check for about a week, and things seemed fine. This was with the water line below the tile, so I would like to think the current older plaster is not leaking. I have smacked the plaster surface in a lot of the pool, maybe 70%, and have found very little to no hollow sounds. It is unfortunate that plaster crews in northern VA charge such high prices and do a sub par job of not removing all older plaster. I have seen a lot of videos on youtube where all plaster is hammered or water blasted off, wonder why the status quo is different here.

To prep the damaged bond beam, do I pressure wash, acid wash, add bonding agent, and then add the concrete?
Should I put anything on the new and old rebar to waterproof it before covering in concrete?
Any particular bonding agent that is recommended?

With the 50/50 plastic cement mix, is that for both bond beam repair and coping mortar? Do you recommend adding thin set to bottom of coping as well?

Thanks again guys.

Edit. Should I chip out the whole pool while I am at it?
Your plan sounds good, no need to do anything to the rebar. Any bonding agent should do but be sure to follow the directions.

I would use thinset on the coping, apply it to the bond beam and the bottom of the coping. Pull up a piece every so often to make sure you're getting good coverage with the thinset and there aren't any air pockets. If applied correctly it should be really hard to lift up a piece of coping you just set.
 
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