Rebar-pool to deck

Status
Not open for further replies.

Onetype

Member
Apr 27, 2021
11
Bastrop Tx
No, it is not separate. Rebar gets bent down and tied into the decking. This is exactly how it’s done on houses. If they did not tie the decking into the shell the decking would sink where it meets the coping.

Its almost self explanatory if you just think about it (not trying to be rude, but it should be common sense). When they pour concrete decks onto the house they tie the rebar into the slab for the exact same reason, then the opposite side will have a footing like a traditional monolithic slab. This is the correct way to do it.

Here’s a picture of what it will look like, you can see the shell rebar bent 90 degrees and tied into the deck rebar.
 

Attachments

  • 7CB34A8E-C72C-47A8-8780-434F470DFB72.jpeg
    7CB34A8E-C72C-47A8-8780-434F470DFB72.jpeg
    661.9 KB · Views: 61
Last edited:

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
29,790
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
No, it is not separate. Rebar gets bent down and tied into the decking. This is exactly how it’s done on houses. If they did not tie the decking into the shell the decking would sink where it meets the coping.

The pool and the deck need to be separate structures separated by an expansion joint. They need to be able to move independently. Otherwise you can develop cracks in the pool or deck as they put pressure on each other.

 
  • Like
Reactions: JamesW

Onetype

Member
Apr 27, 2021
11
Bastrop Tx
There are 2 types of concrete, and only 2 types of concrete. New concrete and cracked concrete. It’s going to crack regardless eventually, the expansion joints are there to control where the cracking happens (that’s why they run perpendicular to the joint). It’s not a matter of if it will crack, but when. It’s much easier and cheaper to fix cracked concrete than sunken concrete.

It will sink if it’s not tied into the shell. This has been common practice in house building for over a century. Look at any slab on grade addition, or any decking addition and you will see it tied into the main structure.
 
Last edited:

JamesW

TFP Expert
Mar 2, 2011
28,291
  • Like
Reactions: duade and kimkats

Onetype

Member
Apr 27, 2021
11
Bastrop Tx
Concrete is concrete bud. Just because you put water in it doesn’t change the physics.

Go ahead, make them cut the rebar. At least when it starts to sink and separate from the coping you can say “well at least I don't have any miniscule cracks to worry about".
 

PoolGate

Gold Supporter
TFP Guide
Jun 7, 2017
6,621
Damascus, MD
Pool Size
29000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Jandy Aquapure 1400
I would think the different types of concrete used in the pool shell and the deck would necessitate them being separate structures. That said, my deck is not tied into my pool in any way. It has about a 1" expansion joint between the two. My deck has sunk a bit in several places below the level of the coping. Not a lot but close to 1" in some places. Fortunately there are no cracks to go along with the sinking and hopefully never will be. I also am hopeful that the sinking is done and won't get any worse. My ground is VERY hard almost like concrete and I attribute the sinking to poor ground prep.
 

Onetype

Member
Apr 27, 2021
11
Bastrop Tx
There are no "different types of concrete". All concrete is made up of the same exact thing, the only difference is method used and different strengths based on mixture ratios. It's all portland cement, aggregate (some use large, some use small), and water. Some companies use adhesion and other additives, some don't.

Not trying to be an a horse's rear, but unless you want your deck shifting constantly (which it absolutely will) in relation to the pool shell/coping, your PB is doing it correctly.
 
Last edited by a moderator:

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
29,790
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Last edited:
  • Like
Reactions: kimkats and JamesW

Onetype

Member
Apr 27, 2021
11
Bastrop Tx
These are both dealing with subgrade and an expansion joint between the tile and coping, which is not what we're talking about. Expansion joint is used regardless, no one is arguing that. It's simply to keep the inner most portion of the concrete level with the coping/shell and keep it from sinking. The decking does not physically contact the pool shell, it's only TIED into it using #2 rebar and does not effect expansion/contraction. What you posted just illustrates shear cracks when adjoining concrete has no place to expand to. Make sense?
 

Attachments

  • 7B2641DB-77B3-4CE1-89DA-FB2B56DCD841.jpeg
    7B2641DB-77B3-4CE1-89DA-FB2B56DCD841.jpeg
    14.9 KB · Views: 7
Last edited:

Enjoying this content?

Support TFP with a donation.

Give Support

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
29,790
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
These are both dealing with subgrade and an expansion joint between the tile and coping, which is not what we're talking about.

If you look closely you will see both designs have an expansion joint between the pool coping/bond beam and deck.

I didn't realize rebar was flexible and could expand and contract to allow movement between the pool and deck. The construction method you are advocating for is maybe why we see so many pools with cracked coping, bond beams, and tiles. I have never seen it specified on any pool engineering drawings.
 
  • Like
Reactions: duade

Onetype

Member
Apr 27, 2021
11
Bastrop Tx
Right, and again the OP isn't talking about expansion joints. No one is arguing expansion joints. Not sure why we keep having to revisit this.

Rebar doesn't need to expand and contract, it simply keeps the concrete from moving up and down. The expansion joint keeps the concrete from EXPANDING into the shell of the pool, which can result in shear cracks. Again, I'm not sure why this is such a hard concept to grasp. The concrete still has an expansion joint. It can still expand and contract. The rebar is ONLY there to keep it from shifting vertically (which is bad for the the deck and aesthetics).
 
Last edited:

JamesW

TFP Expert
Mar 2, 2011
28,291
If you have rebar connecting the deck and the shell, then the rebar will be pushed and pulled by the deck expanding and contracting.

In my opinion, it basically defeats the purpose of the expansion joint.

See where it say No contact?

No contact means no contact.

1627173909418.png
 
  • Like
Reactions: duade

Onetype

Member
Apr 27, 2021
11
Bastrop Tx
Pushed and pulled? Concrete does not expand like that, we’re talking fractions of a mm. It’s the pressure that is exerted on the shell that is an issue with direct contact.

You are thinking about it entirely wrong.

They also serve as a means for bonding the pool shell.
 
Last edited:

cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
8,648
Southern OK
Pool Size
15000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
CircuPool SJ-40
@Onetype You live in TX.. In can move up to 1/2 inch.. most likely 1/4 inch per night... If you tie rebar into the pool shell it will crack your shell/bond beam..

Why you ask...

The pool, because of the water, does not fluctuate in temps.. It may change 2 degrees overnight..

The Math, (I know basic math so you mathematicians back me up ) I am using my new pool as the example.

bond beam and deck = 130 feet..
temp = concrete surface temp..
Bond beam = 86 degrees/night : 88 degrees/day..
deck = 80 degrees night / 130 degrees day..


Bond beam movement = 0.01716 inch

Deck movement = 0.429 inch

If you tie your pool rebar into the deck it will damage your pool long term.. They do not contract and expand at the same amount.. The deck will try to move the bond beam.. Daily it moves... The damage happens daily.. This is why there needs to be an expansion joint at least 1/2 inch thick to allow this movement, if the rebar were connected it would not allow the movement and damage will occur...

This is not even taking in the effect of bad compacting and using dirt as fill under decks.. it will be even worse then.. the rebar from the bond beam will try to hold the deck up.. After the dirt compacts under the deck the bond beam will be holding the entire weight of the deck...

Please for the love of god do not connect your bond beam rebar to the deck...

A general value for concrete's coefficient of thermal expansion is about 5.5 millionths/° F. If an unrestrained, 100-foot-long slab on grade was exposed to a 100° F temperature drop throughout its cross-section, it would contract about .66 inch (100 feet x 12 inches/foot x 100° F x .0000055). Since the slab is restrained by friction between the base and the bottom of the slab, the slab usually cracks instead of contracting the roughly 2/3 inch.

 

Onetype

Member
Apr 27, 2021
11
Bastrop Tx
I guess I should go warn my neighbor who has a ~40 year old pool with original plaster (which is in amazing shape I might add) that she needs to rip up her deck before it damages the shell 😂

I only know this because one of her big pines fell and took a small section of her deck/coping and I saw hers was tied in the exact same way.

Maybe in ~50 years when I’m on my death bed I may have to worry about it, but at least I won’t have a deck that’s sinking and separating within a decade.
 

JamesW

TFP Expert
Mar 2, 2011
28,291
I guess I should go warn my neighbor who has a ~40 year old pool with original plaster (which is in amazing shape I might add) that she needs to rip up her deck before it damages the shell 😂

I only know this because one of her big pines fell and took a small section of her deck/coping and I saw hers was tied in the exact same way.

Maybe in ~50 years when I’m on my death bed I may have to worry about it, but at least I won’t have a deck that’s sinking and separating within a decade.
Ok, thank you for sharing your information with us.

Maybe you are correct that there are some times where it is a good choice.

I will look into it some more as I get a chance.
 

PoolGate

Gold Supporter
TFP Guide
Jun 7, 2017
6,621
Damascus, MD
Pool Size
29000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Jandy Aquapure 1400
I guess I should go warn my neighbor who has a ~40 year old pool with original plaster (which is in amazing shape I might add) that she needs to rip up her deck before it damages the shell 😂

I only know this because one of her big pines fell and took a small section of her deck/coping and I saw hers was tied in the exact same way.

Maybe in ~50 years when I’m on my death bed I may have to worry about it, but at least I won’t have a deck that’s sinking and separating within a decade.
I'm also interested in some references other than anecdotally.
 
  • Like
Reactions: onBalance

Enjoying this content?

Support TFP with a donation.

Give Support
Status
Not open for further replies.
Thread Status
Hello , This is an inactive thread. Any new postings here are unlikely to be seen or responded to by other members. You will get much more visibility by Starting A New Thread