Concrete deck questions… any concrete gurus?

[fun4stuff]

We are having a concrete pool deck poured. Located in Michigan.

There is an 18” stacked paver wall around 2 sides. 4-5’ around the fiberglass pool is mostly rock for drainage. Otherwise the 4 sides of pool will have 14’, 8’, 10’, and 8’ of concrete.

2 issues.

Issue 1:
A neighbor (who has worked in construction and now sells construction material) was telling me i should insist on 2-3’ crushed compacted rock under the concrete to help prevent concrete from cracking.

The guy doing our concrete says sand is better. He is going to add a lot of rebar and some kind of “steel mesh”. 4” thick concrete.

Issue 2.
Initially we were under the impression that we would have an expansion joint between the coping on the wall and the pour concrete. Now concrete guy is saying he can’t do the expansion joint because his forms “won’t fit”. So he’s going to try and make the the gap very narrow and then fill with poly sand.

Some of this info is second hand from my wife, as i was not home when concrete guy was here Friday.

I’m hoping a pro will be able to weigh in on these two issues.

Thanks!

Pics are a couple days old. They have not started prep’ing for concrete yet.

 

[ajw22]

Issue 1:
A neighbor (who has worked in construction and now sells construction material) was telling me i should insist on 2-3’ crushed compacted rock under the concrete to help prevent concrete from cracking.

The guy doing our concrete says sand is better. He is going to add a lot of rebar and some kind of “steel mesh”. 4” thick concrete.

Rebar and steel mesh should keep the concrete from cracking. Having a gravel base would be even better.

Make sure the rebar steel is connected together to meet the NEC 3 foot perimeter bonding requirement and connected to your bonding grid.

Issue 2.
Initially we were under the impression that we would have an expansion joint between the coping on the wall and the pour concrete. Now concrete guy is saying he can’t do the expansion joint because his forms “won’t fit”. So he’s going to try and make the the gap very narrow and then fill with poly sand.

A narrow gap filled with sand can collapse over time until you no longer have an expansion joint. The guy doing your concrete will be long gone by the time you have problems.

If he can do a narrow gap he should be able to do a 3/8"-1/2" gap.

Foam tape should be placed along the edge of the coping and then he builds to that point.

Quikrete 4 in. x 50 ft. Foam Expansion Joint 6917-05 - The Home Depot

Visit the Home Depot to buy Quikrete 4 in. x 50 ft. Foam Expansion Joint 6917-05

www.homedepot.com

Quikrete 1/2 in. x 4 in. x 5 ft. 2 lb. Expansion Joint 691703 - The Home Depot

Get the Quikrete 1/2 in. x 4 in. x 5 ft. Expansion Joint 691703, for in between concrete slabs it is a filler made from resilient cane fibers and is used to prevent damage during expansion and contraction

www.homedepot.com

It sounds like your concrete guy is using forms for a cantilever deck instead of a concrete pour that butts up to an expansion joint on coping.

Expansion Joints and Coping - Further Reading

www.troublefreepool.com

Decorative Concrete Forming Systems and Deck Drains for Swimming Pools | Stegmeier LLC | 817-467-9028

At Stegmeier LLC, we provide the highest quality concreate forming systesms and deck drains for the swimming pool industry across the United States. Decorative Concrete Forming Systems and Deck Drains for Swimming Pools | Stegmeier LLC | 817-467-9028

www.stegmeier.com

 

[fun4stuff]

Rebar and steel mesh should keep the concrete from cracking. Having a gravel base would be even better.

Make sure the rebar steel is connected together to meet the NEC 3 foot perimeter bonding requirement and connected to your bonding grid.



A narrow gap filled with sand can collapse over time until you no longer have an expansion joint. The guy doing your concrete will be long gone by the time you have problems.

If he can do a narrow gap he should be able to do a 3/8"-1/2" gap.

Foam tape should be placed along the edge of the coping and then he builds to that point.

Quikrete 4 in. x 50 ft. Foam Expansion Joint 6917-05 - The Home Depot

Visit the Home Depot to buy Quikrete 4 in. x 50 ft. Foam Expansion Joint 6917-05

www.homedepot.com

Quikrete 1/2 in. x 4 in. x 5 ft. 2 lb. Expansion Joint 691703 - The Home Depot

Get the Quikrete 1/2 in. x 4 in. x 5 ft. Expansion Joint 691703, for in between concrete slabs it is a filler made from resilient cane fibers and is used to prevent damage during expansion and contraction

www.homedepot.com

It sounds like your concrete guy is using forms for a cantilever deck instead of a concrete pour that butts up to an expansion joint on coping.

Expansion Joints and Coping - Further Reading

www.troublefreepool.com

Decorative Concrete Forming Systems and Deck Drains for Swimming Pools | Stegmeier LLC | 817-467-9028

At Stegmeier LLC, we provide the highest quality concreate forming systesms and deck drains for the swimming pool industry across the United States. Decorative Concrete Forming Systems and Deck Drains for Swimming Pools | Stegmeier LLC | 817-467-9028

www.stegmeier.com

Thank you for your response. Seems that there is a lot of geographic variability in practice regarding sand vs gravel base.

Concrete guy ended up graining down coping to flatten it to we could do a proper expansion joint. Used the foam kind of above.

Rebar and steel mesh should keep the concrete from cracking. Having a gravel base would be even better.

Make sure the rebar steel is connected together to meet the NEC 3 foot perimeter bonding requirement and connected to your bonding grid.



A narrow gap filled with sand can collapse over time until you no longer have an expansion joint. The guy doing your concrete will be long gone by the time you have problems.

If he can do a narrow gap he should be able to do a 3/8"-1/2" gap.

Foam tape should be placed along the edge of the coping and then he builds to that point.

Quikrete 4 in. x 50 ft. Foam Expansion Joint 6917-05 - The Home Depot

Visit the Home Depot to buy Quikrete 4 in. x 50 ft. Foam Expansion Joint 6917-05

www.homedepot.com

Quikrete 1/2 in. x 4 in. x 5 ft. 2 lb. Expansion Joint 691703 - The Home Depot

Get the Quikrete 1/2 in. x 4 in. x 5 ft. Expansion Joint 691703, for in between concrete slabs it is a filler made from resilient cane fibers and is used to prevent damage during expansion and contraction

www.homedepot.com

It sounds like your concrete guy is using forms for a cantilever deck instead of a concrete pour that butts up to an expansion joint on coping.

Expansion Joints and Coping - Further Reading

www.troublefreepool.com

Decorative Concrete Forming Systems and Deck Drains for Swimming Pools | Stegmeier LLC | 817-467-9028

At Stegmeier LLC, we provide the highest quality concreate forming systesms and deck drains for the swimming pool industry across the United States. Decorative Concrete Forming Systems and Deck Drains for Swimming Pools | Stegmeier LLC | 817-467-9028

www.stegmeier.com

 

[ajw22]

Concrete guy ended up graining down coping to flatten it to we could do a proper expansion joint. Used the foam kind of above.

After everything is installed it is best to top the foam expansion joint with Deck-O-Seal or Sikaflex 1A.

 

[Bill1974]

Provided the subsoil is compacted well and is not an expansive type of material, settling should not be an issue. Was the neighbors recommendation 2' -3'(ft) or 2"-3"(inches)? 2-3 feet would be great but that would be a lot of work.

Make sure to bond the rebar. Sealing the expansion joint is a good idea as ajw22 recommended. If there are any questionable spots for a safety cover anchor now is the time to dig and check.

 

[fun4stuff]

Provided the subsoil is compacted well and is not an expansive type of material, settling should not be an issue. Was the neighbors recommendation 2' -3'(ft) or 2"-3"(inches)? 2-3 feet would be great but that would be a lot of work.

Make sure to bond the rebar. Sealing the expansion joint is a good idea as ajw22 recommended. If there are any questionable spots for a safety cover anchor now is the time to dig and check.

It was 2-3”. Typo.

Ended up being sand and mesh rebar. Bonded. They compacted all the sand with a mechanical compactor. There is a ton of crushed stone all along the fiberglass pool. A few feet at least. A lot of sand was brought for the rest. As the deck was enacted 18”, as our backyard slopes.

It rained a tone after the sand was brought in. Like record amounts all in a few week period. Hopefully that helps compact it.

I talked to a handful of local concrete guys who all said sand was fine. Our concrete guy said “ that’s what you want”. A couple were saying if we weee on clay, then you would want to have a base of a few feet of compacted sand or some crushed rock.

So we have a retaining wall on two sides. On one side they grinding top cap of the wall flat poured up to it with ann expansion joint.

On the other wall which doesn’t face our house, there is a 2” gap between to concrete deck and retaining wall. Supposedly he could t pour right up to it because the wall was an inch too high for his slope. Couldn’t fit a form?? That’s what he told my wife.

Some people were saying we could put backer rod in and fill with caulk… it’s a pretty big gap though. I’m tempted to just fill with some kind of crushed 3/4 gravel and either leave as is or then fill with that gator poly sand stuff. Thoughts??

At least it isn’t on the end facing our house- deep end of pool, so most loungers will be at shallow end . I think it won’t be too noticeable once we have furniture and plants out.

 

[Bill1974]

Is the concrete sloped to the wall where the gap is? If so I had a similar situation, my contractor said a gap was needed to drain water away. It wasn't possible to pitch the concrete enough to drain to the sides. He was thinking of leaving a couple of feet for a planting in bed. We settles on a french drain that goes to a drywell.

 

[fun4stuff]

Is the concrete sloped to the wall where the gap is? If so I had a similar situation, my contractor said a gap was needed to drain water away. It wasn't possible to pitch the concrete enough to drain to the sides. He was thinking of leaving a couple of feet for a planting in bed. We settles on a french drain that goes to a drywell.View attachment 615232

yes, said the gap was needed for drainage. You hardly even notice the stones