Pool coping all came out

[palmtreeguy]

Hey everyone,

I recently moved into a house with a pool in Phoenix (built in 2008). Inspector flagged a couple loose travertine coping stones before purchase, but I didn’t think much of it at the time, being a first-time pool owner.

Well I just pulled the culprits out to glue them back onto the pool beam, and literally all coping stones came out. All had broken off from the pool beam, but they remained in place from being interlocked. As you can imagine, all of the caulking around the coping stones is cracked or gone. Stones were fixed to beam with gray mortar (pale gray mortar between coping stones and black mortar between tiles & coping).

Now the real treat is that pulling them all out made me realize there is no expansion joint (possibly sand, initially, but no spacer/caulking or any space for any of it). You can’t slide a piece of paper between the coping and decking stones in most places – so I don’t even know how I would waterproof from here (?). Is it a Phoenix thing to not need an expansion joint since temperatures don’t dip below zero? I am resigning to just glueing the coping back to the beam as it was, unless someone has a better idea. Otherwise I think ½” would have to be taken out the back of all coping stones to make room for the expansion joint, but I’m not equipped for that. Considering the pool/decking is 15+ years old, I imagine the bulk of the settling is done, and seasonal variation is not extreme enough to warrant putting in a new expansion joint...? Might be wishful thinking.

This pool was built by the biggest pool builder in town, but they said this was no longer under warranty, and that they didn’t have any records or blueprints to help me out.
After doing a lot of reading on this forum, I would gladly take someone’s second opinion on the way forward. Last thing I want to do is make matters worse, but this has to be a DIY project (that hopefully lasts a couple years).

As it stands, my plan is to:
1-Clean all coping stones of leftover grout with chisel & clean stone bottoms & beam tops with wire brush
2-Glue coping stones back to beam as they were (with polyurethane construction adhesive)
3-Polysand where I can on the side and back of coping stones (most places there is no gap whatsoever so there will be no waterproofing)
4-Caulk between pool tiles and coping bottoms (where there was black mortar)
5-Hope for the best

Any feedback appreciated.

Thank you!

 

[ajw22]

Welcome to TFP.

Coping stones are laid on top of the bond beam and should only be the width of the bond beam. Your stones look like they go over the bond beam and the ground.

The purpose of the expansion joint is to allow the pool structure and deck to move independently. That cannot happened when coping stones couple the bond beam and deck.

I would want to remove the mortar from an area and see how wide your bond beam is and where the ground really starts. And what material is under that thin layer of mortar.

Coping stones should be laid in a bed of Type S mortar. I would not use construction adhesive.

I would clean off an area using an oscillating tool and see what is under that layer of mortar and then have more knowledge in how to proceed.

Expansion Joints and Coping - Further Reading

www.troublefreepool.com

 

[Bperry]

Hey everyone,

I recently moved into a house with a pool in Phoenix (built in 2008). Inspector flagged a couple loose travertine coping stones before purchase, but I didn’t think much of it at the time, being a first-time pool owner.

Well I just pulled the culprits out to glue them back onto the pool beam, and literally all coping stones came out. All had broken off from the pool beam, but they remained in place from being interlocked. As you can imagine, all of the caulking around the coping stones is cracked or gone. Stones were fixed to beam with gray mortar (pale gray mortar between coping stones and black mortar between tiles & coping).

Now the real treat is that pulling them all out made me realize there is no expansion joint (possibly sand, initially, but no spacer/caulking or any space for any of it). You can’t slide a piece of paper between the coping and decking stones in most places – so I don’t even know how I would waterproof from here (?). Is it a Phoenix thing to not need an expansion joint since temperatures don’t dip below zero? I am resigning to just glueing the coping back to the beam as it was, unless someone has a better idea. Otherwise I think ½” would have to be taken out the back of all coping stones to make room for the expansion joint, but I’m not equipped for that. Considering the pool/decking is 15+ years old, I imagine the bulk of the settling is done, and seasonal variation is not extreme enough to warrant putting in a new expansion joint...? Might be wishful thinking.

This pool was built by the biggest pool builder in town, but they said this was no longer under warranty, and that they didn’t have any records or blueprints to help me out.
After doing a lot of reading on this forum, I would gladly take someone’s second opinion on the way forward. Last thing I want to do is make matters worse, but this has to be a DIY project (that hopefully lasts a couple years).

As it stands, my plan is to:
1-Clean all coping stones of leftover grout with chisel & clean stone bottoms & beam tops with wire brush
2-Glue coping stones back to beam as they were (with polyurethane construction adhesive)
3-Polysand where I can on the side and back of coping stones (most places there is no gap whatsoever so there will be no waterproofing)
4-Caulk between pool tiles and coping bottoms (where there was black mortar)
5-Hope for the best

Any feedback appreciated.

Thank you!

The reason the stones are loose is the lack of expansion joint. The deck expands and contract in heat/cold and breaks them loose. Not just in AZ.

 

[palmtreeguy]

Welcome to TFP.

Coping stones are laid on top of the bond beam and should only be the width of the bond beam. Your stones look like they go over the bond beam and the ground.

The purpose of the expansion joint is to allow the pool structure and deck to move independently. That cannot happened when coping stones couple the bond beam and deck.

I would want to remove the mortar from an area and see how wide your bond beam is and where the ground really starts. And what material is under that thin layer of mortar.

Coping stones should be laid in a bed of Type S mortar. I would not use construction adhesive.

I would clean off an area using an oscillating tool and see what is under that layer of mortar and then have more knowledge in how to proceed.

Expansion Joints and Coping - Further Reading

www.troublefreepool.com

Thanks for your input. I was surprised to see the coping stones go past the beam as well. I figured it was years of water getting under there and eating away at some parts of the beam. The beam length matches the length of the coping most places, but I pictured some places where it doesn't. I can dig a bit more tomorrow as you suggest. For now all I know is that previous owner didn't maintain very well... so I wouldn't be surprised if this setup has been going on for a long time and water has been getting in for years on end.

 

[Jimrahbe]

PTG,

Does your pool have an overflow drain, to keep the water from getting too high?

Another possible reason that your coping has come up is the pool water was allowed to get high enough to get under the coping... Between the bond beam and the coping, causing the mortar to fail..

Thanks,

Jim R.

 

[palmtreeguy]

The reason the stones are loose is the lack of expansion joint. The deck expands and contract in heat/cold and breaks them loose. Not just in AZ.Tha

The reason the stones are loose is the lack of expansion joint. The deck expands and contract in heat/cold and breaks them loose. Not just in AZ.

So is there a point at all to mortar them back in without making an expansion joint of my own? (Other than no longer being a fall hazard). Or will they just pop loose every year? The coping stones are so tight, there is no way to make an expansion joint without grinding away at the back of the coping, and I have no idea if that's even possible.

Last thing I want is to mortar them back to the beam, and then the deck pushes them and breaks the beam/pool tiles.

 

[palmtreeguy]

PTG,

Does your pool have an overflow drain, to keep the water from getting too high?

Another possible reason that your coping has come up is the pool water was allowed to get high enough to get under the coping... Between the bond beam and the coping, causing the mortar to fail..

Thanks,

Jim R.

Hi Jim,

Thanks for your input. It doesn't have an overflow drain, as far as I know. There's an auto fill but that's it. The previous owner were barely ever home at all, so it's not impossible the pool could have overflown during the Phoenix rainy months...

 

[ajw22]

So is there a point at all to mortar them back in without making an expansion joint of my own? (Other than no longer being a fall hazard). Or will they just pop loose every year? The coping stones are so tight, there is no way to make an expansion joint without grinding away at the back of the coping, and I have no idea if that's even possible.

Last thing I want is to mortar them back to the beam, and then the deck pushes them and breaks the beam/pool tiles.

You use a concrete saw to trim about 3/8” from the edges of the stones on the deck side. This is assuming the coping stone aligns with the outer edge of the bond beam.

Otherwise you have to plan your expansion joint cut to align with the outer edge of the bond beam as the diagram in post #2 illustrates. If you don’t create the correct gap along the outer edge of the bond beam then your efforts will be worthless.

 

[Jimrahbe]

PTG,

Let's see what @1poolman1 has to say...

Thanks,

Jim R.

 

[palmtreeguy]

Quick follow-up. I went and got an oscillating tool and diamond blade. Grinded most of the mortar off the beam for one tile. Two things:

(1) Beam material seems to be reinforced concrete. I didn't grind all the way through because I don't know how fragile this is, but enough to see the beam material.

(2) Seems to me that the beam is a bit wider than the coping, even in places where it looked shorter (because it was covered in dirt at the edge). It looks like the back edge of the beams are just not clean cut, a bit uneven (maybe eaten by water?), but it definitely goes a bit past the coping. I took out a tile right after the coping (triangle, pictured) and the uneven beam edge was probably 2" further than the coping stone line.

What are your recommendations from here?

 

[Bperry]

Quick follow-up. I went and got an oscillating tool and diamond blade. Grinded most of the mortar off the beam for one tile. Two things:

(1) Beam material seems to be reinforced concrete. I didn't grind all the way through because I don't know how fragile this is, but enough to see the beam material.

(2) Seems to me that the beam is a bit wider than the coping, even in places where it looked shorter (because it was covered in dirt at the edge). It looks like the back edge of the beams are just not clean cut, a bit uneven (maybe eaten by water?), but it definitely goes a bit past the coping. I took out a tile right after the coping (triangle, pictured) and the uneven beam edge was probably 2" further than the coping stone line.

What are your recommendations from here?

You’ve got straight lines on the decking/coping joint which are much easier to cut back with a saw.

 

[palmtreeguy]

Quick follow-up. I went and got an oscillating tool and diamond blade. Grinded most of the mortar off the beam for one tile. Two things:

(1) Beam material seems to be reinforced concrete. I didn't grind all the way through because I don't know how fragile this is, but enough to see the beam material.

(2) Seems to me that the beam is a bit wider than the coping, even in places where it looked shorter (because it was covered in dirt at the edge). It looks like the back edge of the beams are just not clean cut, a bit uneven (maybe eaten by water?), but it definitely goes a bit past the coping. I took out a tile right after the coping (triangle, pictured) and the uneven beam edge was probably 2" further than the coping stone line.

What are your recommendations from here?

Actually let me amend (2): the pool beam does seem to be varying in position around the pool, albeit not by design; pictured are the pool stairs, where you can see that the original beam met the coping line (in middle), but it seems to have gotten eaten away around it.

 

[ajw22]

The bond beam is gunite/shotcrete. You don’t want to cut into the bond beam.

The expansion joint needs to follow the outer edge of the bond beam.

You then fill the expansion joint with foam backer rod and flexible mastic. The expansion joint can be up to 1” wide although a wider joint will use much more mastic to fill it.

How to Caulk Your Pool's Expansion Joint

Ensure the longevity and structural integrity of your pool by mastering the essential skill of expansion joint maintenance with this how-to.

blog.intheswim.com

DECK-O-SEAL: Concrete Pool Deck Products

www.wrmeadows.com

 

[palmtreeguy]

I appreciate everyone's help and answer, I couldn't have tackled this without it.

I'll keep at it, I'm in the process of cleaning up all the mortar and grout off all the coping tiles and beam. If I understand correctly the next step will be to cut-off about 1/2" from the deck to make the expansion joint. Now, what kind of saw would you recommend for this? I have an oscillating tool with diamond blade, but I'm guessing it's not enough to cut travertine pavers.

Also, can I cut the stones in place, or is it too much a risk to hit the beam? The current deck stones are sitting on sand; if I do have to take them out, do I need to be careful about re-leveling them afterwards?

Thanks again!

 

[ajw22]

Concrete Saws - Saws - The Home Depot

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www.homedepot.com

You should be able to rent a concrete saw.

You may want to talk with a local mason about the best tools and methods to trim the stones. They may have some pro tips that can help.

 

[Bperry]

I appreciate everyone's help and answer, I couldn't have tackled this without it.

I'll keep at it, I'm in the process of cleaning up all the mortar and grout off all the coping tiles and beam. If I understand correctly the next step will be to cut-off about 1/2" from the deck to make the expansion joint. Now, what kind of saw would you recommend for this? I have an oscillating tool with diamond blade, but I'm guessing it's not enough to cut travertine pavers.

Also, can I cut the stones in place, or is it too much a risk to hit the beam? The current deck stones are sitting on sand; if I do have to take them out, do I need to be careful about re-leveling them afterwards?

Thanks again!

Depending on how thick the tile is and can be removed for cutting, a tile saw rental could work. Concrete saw rental from Home Depot could also work fine if you cut them all in place. Just lay a long straight 2x4 board in place so the saw runs along the board to keep the saw cuts straight, otherwise they can wander a bit.

An oscillating tool is not gonna cut it.

 

[palmtreeguy]

Thanks for your help on the saw question.

So one more thing came up while I continued cleaning out the beam tops and coping bottoms... How thick is the mortar supposed to be between the coping and beam??

If you look at the pictures, it feels like the backside of the coping (where it meets the deck) has an uneven line for some stones, which then got filled-in with sand. In many places that stuff if 1" deep, and I wonder if that is in fact the mortar, not the beam, and as such, whether or not I should grind it down. Do you think that's the mortar? Those holes go way past the pool tile, so I'm afraid I might break the pool tiles if I grind too deep, and make matters way worse.

I also can't seem to find an ideal mortar thickness for when I apply the new mortar, any recommendations?

 

[Bperry]

Thanks for your help on the saw question.

So one more thing came up while I continued cleaning out the beam tops and coping bottoms... How thick is the mortar supposed to be between the coping and beam??

If you look at the pictures, it feels like the backside of the coping (where it meets the deck) has an uneven line for some stones, which then got filled-in with sand. In many places that stuff if 1" deep, and I wonder if that is in fact the mortar, not the beam, and as such, whether or not I should grind it down. Do you think that's the mortar? Those holes go way past the pool tile, so I'm afraid I might break the pool tiles if I grind too deep, and make matters way worse.

I also can't seem to find an ideal mortar thickness for when I apply the new mortar, any recommendations?

Shotcrete is a very non uniform process. The back side of the beam isn’t going to be uniform but as long as it’s generally the minimum thickness it should be fine. The mortar thickness can vary a lot as well.

 

[ajw22]

The bond beam is never level. Mortar thickness varies to level the coping.

 

[palmtreeguy]

Much appreciated once more!

I finished cleaning the beam and tiles (holy Crud that took way longer than expected). Seemed like 1/4"-1/2" mortar depending on places... I'll do the same thickness when mortaring them back on. Just gotta go find myself a saw now, and hope I don't break any deck tiles while making me a nice expansion joint. Hopefully nothing else comes up!