Repair advice: cantilevered coping w/o expansion joint

RioTubes

New member
May 24, 2020
3
Los Angeles
Greetings,
Our pool was replastered 8 years ago by the previous homeowner. They poured a concrete deck that also serves as coping that cantilevers over the pool tile (see pics). It appears that they did not build this correctly as there is no urethane expansion joint between the tile and concrete coping/patio. The tiles have been falling off one by one for the past 5-6 years.

- What is the most affordable way to permanently fixed this?
- Can this be fixed without replastering the pool?
- how to determine if there is an appropriately sized joint between the tile and pool deck (can the grout be dug out? What should be the minimum measurement of this joint?
- if there is a decent size joint (that has been grouted over), can that be dug out so that a proper urethane joint could be applied?

Separate but related question. In reference to the photo showing the pool deck. We plan to cut the concrete along with blue tape so that we can build a timber deck to the right of the blue tape so that the deck is independent of the concrete pool deck in case we must replace the pool deck in the future (without harming the new timber deck). The contractor could cut the concrete along the blue tape. the narrowest width of the remaining concrete deck would be about 3 feet. Do you foresee any reason why we should NOT do this?

Thank you!
 

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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
21,274
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
See Expansion Joints and Coping - Further Reading for the difference in construction between precast coping with an expansion joint or cantilevered coping.

Your problem is not the lack of an expansion joint but it is likely the builder did not properly prepare the “decoupling” expansion joint to extend across the entire width of the top of the bond beam to allow the deck to move independent of the pool shell. This joint can be created with a 4mm plastic sheet or 2 layers of roofing felt underlayment.

I am not sure what view your second picture is showing. If someone grouted the decoupling expansion joint for the cantilever then it needs to be opened up. It takes a closer examination of your current decking to figure out if it is repairable. Otherwise you can demo the entire deck and rebuild it with either precast coping or properly installed cantilevered decking.
 

RioTubes

New member
May 24, 2020
3
Los Angeles
Allen,
Thank you. The 2nd pic shows the width of the patio deck directly over the pool tile. The pic shows grout between the top of pool tile and bottom of concrete deck. I should have zoomed for a better pic. See attachment.

Would the process of determining whether there is a proper decoupling expansion joint extending across the entire width of the bond beam be as follows: (1) dig out grout between top of tile and bottom of coping for the entire perimeter of pool, (2) stick a 4mm thick object in this joint and measure how many inches the object can be inserted?

Separately, do you have feedback on whether or not is OK to cut the concrete per my original post? While the blue tape is shown to stop, the cut would continue on the same arc, towards soil. Would this destabilize the pool decking?

Thanks,
Mike
 

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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
21,274
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
You need to remove the grout from along the bottom of the deck. Although you may lose tiles if that grout was the only thing holding them on. See what the bottom of the deck is sitting on. I don’t expect there to be a gap but material that the deck can slide on independent of the pool structure.

Removing some of the concrete should not destabilize anything if a good base was prepared. Do you know if you have any rebar or mesh in the deck concrete? I would cut out a small piece along the edge and see what you find to understand the way the deck was constructed.

@bdavis466 thoughts?