Concrete coping/decking continuous rebar and construction joint???

[halleys5]

Most of the way through a new VINYL pool install. For the coping/decking we are doing poured concrete. Our PB wants to do a 12" coping and a separate pour for the wider decking. Coping is cantilevered (styrofoam) forms.

The questions are:
1) Should the perpendicular rebar be stubbed out of the 12" coping and made continuous into the decking? (I believe it should).

2) At the construction joint created between the two, should that joint get a foam expansion material with caulk? Or just pour the decking right up against the coping? Of maybe poured up against the coping but with a thin plastic bond breaker? Something else??

NOTE that the pool walls are steel with a 5" top steel "collar". There is angle bracing about every 5-6' all the way around the pool which will bridge BOTH the coping and the decking. i.e. there will be equal support for the coping and about the first 2' of decking.
There is no concrete bond beam at the top of the pool.

No questions on the bonding, I can sort that out regardless of the solutions above.

Thanks in advance!

 

[Jimrahbe]

5,

I would vote no... Later in life you might want to replace the coping.

That said, I have no idea what is "correct'...

Let's see what @1poolman1 has to say...

Thanks,

Jim R.

 

[proavia]

I also vote no.
I believe the coping and decking need to be able to move independent of each other and the joint between the two filled (and maintained) with the proper joint compound.

 

[1poolman1]

Though I'm not a builder, every seminar I took (that made me decide I didn't want to build pools, I'm not that patient) had separate coping and deck always able to float freely apart from each other. Had to do with the differing stresses in the different materials, I believe.

 

[Bperry]

Most of the way through a new VINYL pool install. For the coping/decking we are doing poured concrete. Our PB wants to do a 12" coping and a separate pour for the wider decking. Coping is cantilevered (styrofoam) forms.

The questions are:
1) Should the perpendicular rebar be stubbed out of the 12" coping and made continuous into the decking? (I believe it should).

2) At the construction joint created between the two, should that joint get a foam expansion material with caulk? Or just pour the decking right up against the coping? Of maybe poured up against the coping but with a thin plastic bond breaker? Something else??

NOTE that the pool walls are steel with a 5" top steel "collar". There is angle bracing about every 5-6' all the way around the pool which will bridge BOTH the coping and the decking. i.e. there will be equal support for the coping and about the first 2' of decking.
There is no concrete bond beam at the top of the pool.

No questions on the bonding, I can sort that out regardless of the solutions above.

Thanks in advance!

It depends on how the coping is (or isn’t) bonded to the pool walls. Generally you want the coping to move independently of the surrounding deck so that expansion and contraction of the large flat deck will not put pressure on the pool wall. But I don’t know how the coping on that is secured so hard to say. You definitely don’t want any part of the pool structure tied into the decking, and ideally you have at least a 3/8” expansion joint between the coping and decking if the coping is not part of the decking. For cantilever decking, you want something under the decking to allow it to slide over the top of the pool structure without damaging it when the decking expands.

 

[Jimrahbe]

Calling @bdavis466

Any thoughts on this one??? Long time, no see!!!

Thanks,

Jim R.

 

[bdavis466]

I would want the coping completely isolated from the decking with foam and sealant in the expansion joint. I would build an expansion joint on the angle bracing so the deck movement won’t push on them and to keep the pool walls free of the the expansion forces.

Perhaps a safer option is to make the coping extend to the end of the bracing so it all becomes one unit and then start the deck with an expansion joint from there.

In full disclosure I have never seen a vinyl liner pool in person so my advice is worth about as much as you paid for it

 

[halleys5]

Appreciate all the input!
The coping won’t be “connected” to the pool wall, but between the bonding lugs and concrete over pour, I’m sure it won’t truly be free floating either.

 

[jkhamr]

I've only completed building my first pool for myself, just finished the last concrete pour today. I have however been in the construction industry for 36 years, have owned an architecture firm for 28 of those years providing design and c.m. services mostly on commercial projects. With that said, assuming you've backfilled your pool walls with 1-1/2" +/- limestone rock, you should not see any relevant movement between your pool wall and pool deck. In my opinion your coping and deck should be poured at the same time unless you are wanting to color or stamp your coping something different than the rest of the deck? If you are doing tow separate pours, I would still dowel the coping and deck together but separate them with expansion foam and caulk the joint.

 

[halleys5]

I've only completed building my first pool for myself, just finished the last concrete pour today. I have however been in the construction industry for 36 years, have owned an architecture firm for 28 of those years providing design and c.m. services mostly on commercial projects. With that said, assuming you've backfilled your pool walls with 1-1/2" +/- limestone rock, you should not see any relevant movement between your pool wall and pool deck. In my opinion your coping and deck should be poured at the same time unless you are wanting to color or stamp your coping something different than the rest of the deck? If you are doing tow separate pours, I would still dowel the coping and deck together but separate them with expansion foam and caulk the joint.

Thanks J
I thought about dowels but then pictured my concrete guy's expression when I tell him that's what I want.. Probably the best approach though.

Interestingly, your pool setup is VERY similar to my new one that is under construction.
28,000 Hydra, 4' steel w/8' deep end, 2.25HP superpump, Hayward SWG, 140k BTU heater... no slide or board for me though.
Congrats on your final concrete. All ready for next season!!

 

[MAPR-Austin]

Perhaps a safer option is to make the coping extend to the end of the bracing so it all becomes one unit and then start the deck with an expansion joint from there.

This is my thought as well. Doesn't make sense to me to have the wall brace potentially subject to pressure from deck movement.

On first glance I feel like I would be to have the top of the walls tied into the coping for additional strength, but I assume there is a reason why that is not done. It would certainly make any future renovation or coping replacement much more labor intensive, and potentially catastrophic if they went to tear the coping out with a machine.

 

[jkhamr]

Thanks J
I thought about dowels but then pictured my concrete guy's expression when I tell him that's what I want.. Probably the best approach though.

Interestingly, your pool setup is VERY similar to my new one that is under construction.
28,000 Hydra, 4' steel w/8' deep end, 2.25HP superpump, Hayward SWG, 140k BTU heater... no slide or board for me though.
Congrats on your final concrete. All ready for next season!!

Good luck with getting yours wrapped up! We've actually been using ours for about 3 weeks, so we did have some good times this year, probably going to do the last of my homework on winterizing and close it down in the next couple weeks.

 

[jkhamr]

Thanks J
I thought about dowels but then pictured my concrete guy's expression when I tell him that's what I want.. Probably the best approach though.

Interestingly, your pool setup is VERY similar to my new one that is under construction.
28,000 Hydra, 4' steel w/8' deep end, 2.25HP superpump, Hayward SWG, 140k BTU heater... no slide or board for me though.
Congrats on your final concrete. All ready for next season!!

I also just noticed another similarity, I've got taylor juniper trees coming on Thursday, looks like the same trees at the back of your pool!

 

[bdavis466]

I've only completed building my first pool for myself, just finished the last concrete pour today. I have however been in the construction industry for 36 years, have owned an architecture firm for 28 of those years providing design and c.m. services mostly on commercial projects. With that said, assuming you've backfilled your pool walls with 1-1/2" +/- limestone rock, you should not see any relevant movement between your pool wall and pool deck. In my opinion your coping and deck should be poured at the same time unless you are wanting to color or stamp your coping something different than the rest of the deck? If you are doing tow separate pours, I would still dowel the coping and deck together but separate them with expansion foam and caulk the joint.

You are correct that the pool won’t move, but the deck will and that’s how damage occurs. The concrete decking expands and contracts daily with the changes in temperature and typically the path of least resistance is that big gaping hole it’s wrapped around… the coping needs a true expansion joint, completely isolated from the deck, 1/2” minimum width and sealed to prevent water and debris from entering the joint. If the pool is in an area subject to a freeze/thaw cycle or expansive soils then this is even more important since there is a possibility of heaving.

The skimmer and auto filler (if present) should be tied to the coping, not the decking. You don’t want either of those (and their associated plumbing) riding along with any deck movement. That’s how skimmers crack.

Here’s a really good post by a really good looking humble guy on the topic

Expansion Joints and Coping

Expansion joints – or more appropriately called isolation joints – are an essential part of constructing a structurally sound pool and deck. Concrete (and other similar decking options) expand and contract with changes in temperature which make an expansion joint necessary to prevent the deck...

www.troublefreepool.com

 

[bdavis466]

On a steel walled pool, the expansion joint is that much more important because the walls aren’t nearly as structurally sound as 12 inches of reinforced Shotcrete yet cracked coping and horizontally sheared bond beams are very common from overlooking the expansion joint.

Do a search on this forum “bond beam repair” and just about every thread is a result of not having an expansion joint. That’s exactly what led me to make that post describing that isolation joint.

Perhaps the steel walls are designed to flex somewhat but why risk taking that chance instead of just constructing it properly to begin with and completely isolating it?

 

[bdavis466]

Additionally, on this type of pool I would not recommend cantilever decking in lieu of coping. That type of construction is difficult enough to execute on a concrete shell and would be even more difficult on steel walls

 

[jkhamr]

Additionally, on this type of pool I would not recommend cantilever decking in lieu of coping. That type of construction is difficult enough to execute on a concrete shell and would be even more difficult on steel walls

I think people have some confusion with the term "coping". I have an aluminum bullnose, an actual coping, on top of my metal panels that the pool deck is poured into and it remains in place. I wouldn't pour a 12" strip of concrete then come back and pour a wider pool deck. A concrete cantilever should be poured as one piece with the rest of the pool deck, 5"-6" thick with rebar at 12" o.c., then saw cut for expansion control. Even if you were coloring and stamping, you'd pour as a whole, then mark off the pattern areas to color and stamp. If we're talking about an actual stone coping there should be expansion between the pool deck because as you said varying materials expand and contract differently and you'd expect some surface variation. Until water is in the pool, the metal panel of the pool kit basically serves as a retaining wall for the rock backfill, typically the rock backfill is the same depth as the metal panel and 36" wide. The cantilevered pool deck bears on the rock not the metal panel, no structure necessary from the metal panel for the pool deck to bear on. There should be expansion and a reveal between the top of the metal panel and the bottom of the cantilevered pool deck with caulk between the liner track and bottom of the cantilevered pool deck. Movement of the metal panel wouldn't affect the concrete pool deck unless the backfill is done wrong. The op was talking about their concrete contractor pouring a 12" cantilevered concrete "coping", then coming back and pouring the rest of the concrete pool deck. If that's what they're doing, it's no different than any other concrete cold joint and should be doweled together with rebar.

 

[bdavis466]

Saw cuts are control joints to guide cracking, expansion joints are completely isolated from one surface to the next.

If the pool is designed for cantilever decking, then absolutely the rebar should extend from the bullnose on into the decking. This does not replace the need for an expansion joint since it will need to be on top of the pool wall to prevent the decking from placing forces on the walls and bracing.

The skimmer will need extra attention since it is fixed to the pool wall, but the access will be encased in the decking which are two separate structures that move independently.

@jkhmr, My responses in this thread were directed at the original question since the construction that you’re planning on yours is a different application and I didn’t want the two to get confused.

Sounds like you have it planned out

 

[jkhamr]

b, we're on the same page! I enjoy the conversation, always good to have input from pool building experts. My pool building experience is very limited, but I have designed many hotels and private residences with pools and there's a great crossover in construction methods from pool construction to the building sector. I am always looking for different, better, more cost affective methods of constructing anything. I did not isolate my skimmer, your suggestion in hindsite makes sense, hopefully that won't come back to bite me. I'll make sure to include that detail in the next project I work on.