Cantilever Decking Best Practices - Decking to tile to pebble-plastic between?

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alphadog

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Jul 17, 2013
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I am re-tiling my pool (3rd time this has had to be done as first time the frostproof tile failed at being frost proof, and second time installer installed wrong) and so do it right, i am doing it myself. Gunite pool, plaster finish, old tile removed and surface is clean and flat (chipping and grinding done).

Anyway, I see many people recommend caulk between tile and coping, and i m trying to determine why. I understand a cantilever deck needs to float on the beam and expand, and usually cove strip is used. But if the coping is attached to the top of the beam, and so is the tile, then why caulk and not just grout the joint? If caulk is a just in case mechanism in case coping moves, then i can see that.

I also have seen some really odd suggestions on this forum - (old threads) like use pool putty for the gap. If i were caulking I would expect that a non-self-leveling Urethane should be used. I have seen deck-o-seal one step listed, or Vulkem, but reviews seem mixed.

Anyone got a recommendation from experience?
 
I have always grouted that joint and see no reason why caulking should be used unless you have a cantilevered deck.

I don't see how that would change anything if you're in the area that freezes but in full transparency where I live people wear Snow jackets when it's 65 degrees out ... we consider that freezing
 
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Thanks for the feedback.. i worked for a pool company in my younger days, but we always poured cantilever and used the plastic cove edge. I was in Virginia and there was snow. In Ohio now with similar seasons.

Even if the grout line cracks due to some coping movement, i can't see that taking the tile with it. I see cantilever decks as a different animal as they are not attached to the beam as coping is.

I know this joint can crack though, and I don't want to worry about water getting in there. I go back and forth. :)
 
the reason caulking in freeze conditions is movement. everything expands and contracts differently inside and outside. if its just grout it will hairline crack and the coping when raining or melting snow will use water adhesion to run right down the curve of coping and start weeping into the hairline crack. then it freezes and the whole thing repeats eventually leaving a large crack that lets enough water in to pop something up or out. flexible caulking that is high grade is whats used primarily many different brands out there, even silicone works
 
jimmythegreek said:
the reason caulking in freeze conditions is movement. everything expands and contracts differently inside and outside. if its just grout it will hairline crack and the coping when raining or melting snow will use water adhesion to run right down the curve of coping and start weeping into the hairline crack. then it freezes and the whole thing repeats eventually leaving a large crack that lets enough water in to pop something up or out. flexible caulking that is high grade is whats used primarily many different brands out there, even silicone works
Click to expand...

I guess i am surprised that the coping which is adhered to the bond beam via thinset/mortar would expand/contract and not pop off, and the same could occur for the tile, but yet the joint between them would move enough to crack when they are both adhered to the beam with the same mortar/thinset.

I would think the same mortar that cracks at a joint would crack when being used as an adhesive.
 
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@ajw22 is it industry standard or common practice to lay a thin film plastic over the bond beam prior to pouring the coping or cantilever decking over it to allow for movement or “float”?
What are best practices for installing cantilever decking to allow for expansion/shifting..
Thanks
 
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bdavis466 said:
I have always grouted that joint and see no reason why caulking should be used unless you have a cantilevered deck.

I don't see how that would change anything if you're in the area that freezes but in full transparency where I live people wear Snow jackets when it's 65 degrees out ... we consider that freezing
Click to expand...
Are there best practice methods in installing cantilever decks or threads on TFP? Does the poured concrete deck need to “float” and not bond to the bond beam of the pool where the coping normally would go?
How is this accomplished (using thin film plastic over the bond beam prior to pouring the cantilevered deck?)
 
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I think industry standards and common practices are all over the map. The construction buildup should be discussed with the builder and specified in the contract. Nothing should be assumed as a standard practice with a pool builder.

Something to keep the coping floating is recommended. I have heard some builders put just a layer of sand down. Plastic is better I think.

You definitely want to keep the coping and deck floating to prevent cracks.

@bdavis466 @MinerJason thoughts?
 
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duraleigh said:
I used roofing felt paper. More durable than plastic, It was easy to put down, stay down and work with.
Click to expand...
Agreed, 2-3 layers of 30# roofing felt is typically called out on the engineering for cantilevered pool decks.

Make sure that the soil / compacted base is at the same height as the bond beam so the decking doesn't have anything to push against when it expands.

See the detail below:

Screenshot_20190728-112301_Chrome.jpg

Screenshot_20190728-112301_Chrome.jpg

 
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Thanks for the speedy response. Much appreciated. So this is where I’m at...
Let me know if you see any issues.

Kind of tricky to fade in the new decking with existing patio concrete slab.
I see more base needed at that spot but that will thin out my decking slab...(if I dont fill in then I don't have the full deck "floating" as it will hit the notch on the bond beam)
Rebar should sit midpoint between bottom surface and finished grade.

The drainage is set up to where the surface water on the deck will drain to the middle between the house and pool and into the drains.

Thoughts?

21229683-243E-46FA-9E0D-23F340994150.jpeg
 
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