Best coping-to-concrete deck gap sealant

[MAPR-Austin]

Thank you. Yes, I was wondering about a narrower strip of stone too. Although I didn't measure it everywhere, the Bond Beam was about 12-1/2" wide, but it could be more, could be less-- I don't believe any great care was taken to have a consistent shell thickenss beyond whatever minimum they felt they needed. The coping hangs over into the pool by about 1-1/4 - 1-1/2, so there is about 2" wide of leftover of Bond beam to "grab" onto by any mortar bed that supports the stone... could be as much as 2-1/2". To get the min 1/2" clearance from the bond beam to the concrete slab, the saw cut will need to be at least 3"... So in theory, I could use a smaller 2" wide strip to fill a 3" cut... the 2" strip will be supported by at least 1-1/2" of Bond Beam. I spoke to a friend that can get me the stone and he said that "chopping" a 4" wide stone strip was tricky enough, so I doubt chopping 2" wide strips of stone ( I think "Silver Mist" would be the stone) is possible. They'd have to be sawcut. And the other issue with a narrower cut in the concrete is if they cut through a bond wire, IDK if they'd be able to find (or have room to find) any rebar to grab onto to re-establish the grounding... I wonder if we could just drive a grounding rod into the soil and attach to that instead. But even that won't be easy-- once you get down about 5', it's solid Limestone, so any rod will need to be driven at an angle, and in a very narrow cavity. There's still a labor shortage in my area so although I may contract with a remodeler that knows his stuff, I may wind up with a day-laborer that I wont be able to communicate with and may not understand the delicate nature.

And thanks for the tip on the expansion material "strip". That works better than the backer rod?? I looked it up..... I was wondering how one would keep the mortar from the stone install away from the deck slab & maintian a positive 1/2" min joint. -- an adhesive foam strip would do it. And that strip stays in permanently?

Understood on the stone, I figured it would have to be saw cut. Your concern on the bonding wire makes sense.

Yes, the lower part of the strip stays in place. You'll want some construction adhesive to stick it to the concrete, it is not self adhering.

Maybe pop some tapcons into the pool shell and hope that serves as some reinforcement to hold the mortar in place? You could fill the area you have marked on the drawing with grout to give it a bit more body. I tried to illustrate the idea on your drawing.

I don't think a ground rod would suffice - you really don't want to cut corners on bonding. Low risk of a problem, but the consequences of that problem could be catastrophic or deadly. You could have a bonding test done before the pour to confirm the continuity of the bonding grid.

 

[KevMo]

I wonder if we could just drive a grounding rod into the soil and attach to that instead.

See the article below for a detail description about bonding and how it is different than grounding. To quote an excerpt: "Bonding is used to equalize voltage potential differences to reduce shock hazards between different parts of the pool by connecting potentially conductive parts together. Grounding involves providing a low-impedance, ground-fault return path from the equipment required to be grounded back to the source of the electrical system, typically through the equipment grounding conductor routed with the branch-circuit conductors. "

Electrical Bonding - Further Reading

www.troublefreepool.com

 

[pwa2003]

Understood on the stone, I figured it would have to be saw cut. Your concern on the bonding wire makes sense.

Yes, the lower part of the strip stays in place. You'll want some construction adhesive to stick it to the concrete, it is not self adhering.

Maybe pop some tapcons into the pool shell and hope that serves as some reinforcement to hold the mortar in place? You could fill the area you have marked on the drawing with grout to give it a bit more body. I tried to illustrate the idea on your drawing.

I don't think a ground rod would suffice - you really don't want to cut corners on bonding. Low risk of a problem, but the consequences of that problem could be catastrophic or deadly. You could have a bonding test done before the pour to confirm the continuity of the bonding grid.

Thank you---- yes, your diagram helps. that would be a lot of tapcons, but I see where youre going with that. If I can create a solid enough extension to the bond beam, the support for the stone will take care of itself and I wouldn't need the decomposed granite or gravel. And really, the narrower I make the sawcut & removal of the concrete deck, the less access I'd have to the soil between the bond beam and the new edge of the deck.... but a narrower cut/removal would also would mean less unsupported/cantilevered stone. The thickness of the Bond Beam varies, but I'm expecting about 2" (plus or minus 1/2") of exposed bond beam once we saw back & remove the concrete. If I can get 51% of that stone inlay to rest on top of the existing Bond beam, I might just live with the cantilever (with unsupported mortar or less density of tapcons).

And If I were to cut & remove a smaller amount-- only 3-1/2", for example-- I may only have access to about 1" of soil in some spots, and 1/2" - 5/8" of that 1" will be consumed by the expansion foam strip (which I've still NOT sourced).. The goal in all of this is still to clear the deck from the Bond Beam by a minimum of 5/8", and a 3" -ish cut would probably do that. I could just fill that gap with one huge sealant joint, but it wouldn't look pretty... Anything beyond 3-ish" concrete removal is just to ease the installation of the stone and expose any of the deck rebar to re-establish bonding if they cut the wires. And cutting a wider space between the deck & coping (4-5", for example) slightly helps the heaved condition in the deck since the deck slopes away from the pool.

I did find a place that would "chop cut" 1-inch thick flagstone into 4" wide strips. I prefer that "chopped" live edge to the sharp edge of a saw cut..... But that service wasn't cheap ($13/ LF). My contact at another stone yard has much less inventory and is limited on what he's willing to do for free, but he can saw cut some stone, and if I can find a way to mangle those straight parallel edges to look like a chop cut, I'll probably do that. And funny enough-- I havent decided on the preferred order of events-- whether to saw cut the concrete deck and define the gap first, or cut the stone first and size the concrete deck gap based on the stone. I'm pretty sure I'd rather size the stone second and cut the concrete first.

 

[pwa2003]

See the article below for a detail description about bonding and how it is different than grounding. To quote an excerpt: "Bonding is used to equalize voltage potential differences to reduce shock hazards between different parts of the pool by connecting potentially conductive parts together. Grounding involves providing a low-impedance, ground-fault return path from the equipment required to be grounded back to the source of the electrical system, typically through the equipment grounding conductor routed with the branch-circuit conductors. "

Electrical Bonding - Further Reading

www.troublefreepool.com

OK-- Thank you. This is a big help. I've been using "bonding" and "grounding" interchangibly, and that's not the care at all.. As far as I know, the only metal in the pool is the rebar in the shell and the rebar in the deck. The lighting is presumably the lo-voltage LED ( Hayward LACUS11 ColorLogic LED). I thought the skimmers were all PVC, but maybe I'll go back and look at the literature.

My Electrician tells me "not to worry about it" , but it's too late for that. He properly grounded all the equipment at the equipment pad with a grounding rod, but other people did the pool bonding-- which was fine when the inspector left the jobsite.... but then they came back two days later and possible sawed right through the wires..... so maybe I should cut back this deck enough to expose a piece of the deck rebar--- just in case.

 

[MAPR-Austin]

OK-- Thank you. This is a big help. I've been using "bonding" and "grounding" interchangibly, and that's not the care at all.. As far as I know, the only metal in the pool is the rebar in the shell and the rebar in the deck. The lighting is presumably the lo-voltage LED ( Hayward LACUS11 ColorLogic LED). I thought the skimmers were all PVC, but maybe I'll go back and look at the literature.

My Electrician tells me "not to worry about it" , but it's too late for that. He properly grounded all the equipment at the equipment pad with a grounding rod, but other people did the pool bonding-- which was fine when the inspector left the jobsite.... but then they came back two days later and possible sawed right through the wires..... so maybe I should cut back this deck enough to expose a piece of the deck rebar--- just in case.

You can always just splice the copper bond wire together with a lug, you don't have to go all the way back to the rebar as long as you can get at both ends of the wire. It will take some time and a smooth hand with the chipping hammer but it can be done in surprisingly tight quarters.

 

[pwa2003]

Thanks again everyone. Looks like this deck saw-cut & srtip of concrete removal will occur next week. I found a professional cutting service that's done a few of these and knows what they're doing and hopefully limit the mess from going into the pool.... Then I can replace the broken travertine and add the stone inlay... and create a proper expansion joint.

Identifying the right sealant for that joint has been tougher than I thought. I've looked at SikaFlex, Latisil, Vulkem 45, and now the Deck-O-Seal HS-1SL (single part in 32 oz nozzled pouches). I wanted something in a darker gray color to better match the mortar that'll be in the adjacent joints, and possibly add a "finishing sand" to the outer surface of the sealant while it was still wet to give it more of a mortar look.

The Deck-O-Seal seems to come in a darker "Stone Grey" that may be suitable... if I can get my hands on a color chart or photo of installed sealant. The Sikaflex was definitely runny and self leveling, but too light of a Gray. The Tremco (Vulkem) website was too difficult to find the info I wanted, so I shelved that for now, and the Latisil is still an option but I havent yet found a good color sample.

Can anyone vouch for these sealant products? I bought a few rolls of 1/2" x 4" expansion pad to adhere to the new concrete deck expansion joint face, although I may need something a bit thicker to create a tighter fit. I'd like to get it all wrapped up by the end of October. Nothing like waiting till the mast minute....