Concrete Control vs. Expansion Joints

[scottkotzur]

I recently removed several poured concrete slabs from around my pool. I didn't remove ALL of the concrete because a lot of it is still in great shape and didn't need replacing. the ones I removed though were cracked, uneven, posed a toe-stubbing hazard and were unsightly. I am currently in the process of grading the soil after which which I will tamp, lay down several inches of gravel and finally tamp again. I'm hoping this will provide adequate drainage and support for exceptional longevity.

My confusion is about the joint type I should be using. I've been reading a lot about different joint types, and the more I read the more indecisive I get.

Expansion joints I understand are to be used between poured slabs and anything that is immovable such as the footings to a house, a retaining wall, or in this case the pool.
Control joints are regularly spaced joints that cause the concrete to crack at that joint as the concrete contracts during the curing process instead of cracking randomly throughout the slab.

My questions are:

1. What type of joint should be installed perpendicular to the edge of the pool out to the edge of the form (circled in blue on diagram)?
2. What type of joint should be installed where the new concrete meets the old (circled in red on the diagram)?
3. What type of joint should be installed at the corner of the steps (circled in green on the diagram)?

My gut feeling is that all of these should be control joints, but I just want to make sure before proceeding.

Some follow up questions:

1. what are people's opinion of Zip-Strip or similar materials?
2. What are people's opinion of this product: http://www.deckoseal.com/02/07/deck-o-joint-vinyl-decorative-control-joint/

I'm having a concrete truck come on Saturday and would like to pick up the material either tomorrow or Friday (7/21/16 or 7/22/16) so the sooner you can get back to me the more awesome I'll think you are Thanks in advance for the help!

 

[gwegan]

It depends. I would put in expansion joints at all your locations if I could because they will allow for greater flexibility and movement. Deck O Seal is good stuff. With your extremes of temperature against a immovable object like a pool I would avoid control joints entirely.

Of Vital importance:

The National Electrical Code generally requires that you place a metal or copper grid or mesh 3 feet around your pool under the deck and connect it to the bonding system in your pool. You should make sure the bonding wire mesh or grid under the existing deck is also connected to the bonding system. If you don't know how to do this ask for help or have a qualified electrician perform the work.

 

[Pool Tool]

Red should definitely be expansion joints. Blue and green would be not worth the additional effort to pour separately, so I believe control joints would be fine there. With the green (really only 0.75" wide) I would make the control joint large enough to use Deck o Seal on it because it will likely separate there with any settling. Zip Strip is good stuff, just make sure to install the perforation towards the top

Any bonding installed should also include the stair handle if you are installing one.

 

[scottkotzur]

With the green (really only 0.75" wide) I would make the control joint large enough to use Deck o Seal on it because it will likely separate there with any settling.

Doh. I draw this up in inventor using inches. I did not mean to have any dimensions showing, but since you've seen it...I used inches just because that's the standard units I have set up. That's actually .75 feet or 9 inches; still a very short joint, but not .75" as is called out in the diagram.

 

[Pool Tool]

haha, always the unintended that's noticed. 9" is a much better scenario. Good luck with the pour, hopefully the real hot weather won't be to you by then and set that concrete too fast!