Cantilever deck new pour surface cracks

[RodB]

Hello, all over 18 months into my build I decided to general contract the pool. COVID kinda messed things up but after 37 years in the army I thought it would be rather easy. So here’s my issue the concrete contractor poured my cantilever patio and all seemed great until a week after I noticed very small cracks at the pool edge in about 15 locations. They extend from the control joints that are in the patio. He will fix it, he’s recommending a skim coat on only the cantilever edge where all the cracks are located. He said it will hold up just wanted to know if anyone had experienced this. The patio can’t be tied to the pool beam because of potential movement. I just don’t know how that could be avoided. Thanks in advance for any suggestions as long as it’s not demo the pool and start over. I’ve attached some pics. Thanks to this great forum!

 

[ajw22]

What type of pool do you have?

Please show some wider pictures of the area to put in context what we are looking at here...

 

[AQUA~HOLICS]

Skim coat is a patch and not a correction to the problem. Keeping the patio concrete separate from the pool bond beam is done with a membrane installed between the two.

 

[RodB]

What type of pool do you have?

Please show some wider pictures of the area to put in context what we are looking at here...

 

[RodB]

View attachment 410714

 

[RodB]

Skim coat is a patch and not a correction to the problem. Keeping the patio concrete separate from the pool bond beam is done with a membrane installed between the two.

Yes I have the membrane in place between the beam and deck. Thanks

 

[ajw22]

View attachment 410714

That pic does not help.

This pic shows three different surfaces.

What are those three surfaces and what am I looking at?

Is this a horizontal slice? A vertical slice?

 

[AQUA~HOLICS]

This is how I see it…..

 

[ajw22]

This is how I see it…..

You don't have separate deck and coping layers with a cantilevered deck. The cantilevered deck is the coping.

And is that pic upside down with the gunite on top?

I asked what type of pool it is and got no answer

Confused!.

 

[RodB]

That pic does not help.

This pic shows three different surfaces.

What are those three surfaces and what am I looking at?

Is this a horizontal slice? A vertical slice?

View attachment 410734

Sorry those pic were for the contractor. I’m not at home I will post better photos of the pool with cracks . Thanks for the quick reply!

 

[AQUA~HOLICS]

looks Like the picture was taken looking straight down from standing on the deck. My wording was trying to explain how the pool owner is describing the picture. Type of pool looks like a Shotcret/Gunite type shell.

 

[RodB]

looks Like the picture was taken looking straight down from standing on the deck. My wording was trying to explain how the pool owner is describing the picture. Type of pool looks like a Shotcret/Gunite type shell.

Exactly standing in the patio looking straight down at the crack which is on the edge of the pool the other surface is the bottom of the pool

Thanks

 

[RodB]

Exactly standing in the patio looking straight down at the crack which is on the edge of the pool the other surface is the bottom of the pool

Thanks

It’s shotcrete

Thanks

 

[RodB]

I attached some better photos just follow the control joint in the patio and zoom on last photo and you’ll see the crack.

 

[ajw22]

I think it is an issue that the cracks follow the control joints on the patio. That is what I wanted to see.

The patio has control joints which are there to control the cracking that concrete always does. But the faux coping does not have equivalent control joints and the cracks are making their own.

The skim coat is not going to stop the cracks from reappearing likely at the same points. All that concrete is tied together and the natural stresses need to be released and the control joints are focusing it on those points.

Rather then a skim coat control joints should be saw cut into the cracks.

 

[RodB]

What if he skim coats and put control joint in the skim coat? What’s the other option live with the cracks? Thanks

 

[AQUA~HOLICS]

The control joint needs to be be deeper than just the skim coat in order to keep the controlled cracks straight.

 

[ajw22]

From

Control Joints in Concrete - When To Cut & Spacing - Concrete Network

Tips for cutting control joints in concrete slabs including information about when to make cuts, depth, proper spacing, corners, and more.

www.concretenetwork.com

Control joints are planned cracks which allow for movements caused by temperature changes and drying shrinkage. In other words, if the concrete does crack-you want to have an active role in deciding where it will crack and that it will crack in a straight line instead of randomly.

...

Cut joints 25% of the depth of the slab. A 4" thick slab should have joints 1" deep.

 

[RodB]

The control joint needs to be be deeper than just the skim coat in order to keep the controlled cracks straight.

So skim coat and cut control joints through the skim coat and into the orginal concrete?

If that what it takes I’ll go with that and the contractor probably already planned on doing that.

I guess with control joints in the cantilever look oh well I’ll take it if it holds up.

Thanks

 

[Jayphil]

Your cantilever coping seem to be poured concrete with a mold to make it look like removable coping blocks. The coping should have been cut at the same place as the patio relief cuts unless is it really an isolated coping properly separated.

I decided not to make a faux-coping and keep the patio and coping one piece but the principle is the same, my relief cuts are going to the border of the pool so that the cantilever if it cracks it will exactly a that place.