Flag Stone Coping Redo - Advice Needed

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T

troye

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Apr 10, 2013
103
Sunny SoCal
Pool Size
15000
Surface
Plaster
Chlorine
Liquid Chlorine
Hello,

Unfortunately this Summer has been a summer without the enjoyment of our pool, for a couple of reasons. One of the reasons is our flag stone coping we had re-done a couple of years ago was loose.

I had to remove a section about 1/3 of the pool that was loose. There is another section that is not loose but lifts a little, it is not a safety issue and I don't want to turn this into any larger of a project so I will wait until next season.

This is the first time I have done anything like this so I am a little lost. I have done some reading on TFP which is helpful, but I still have some questions.

It appears there are different layers of mortar. There was a top layer which I removed and then there is a solid base of mortar. On 1/2 of the section I am working on I have removed all mortar, on the other 1/2 it still remains. The pool wall / beam is in good shape, no cracks or anything.

There is a 3-4" space that separates the pool wall from the cement deck. This has / had mortar there. I removed any hollow sounding mortar which was most of it. I identified some delaminated pebbletech that was removed.

1. Do I need to remove the solid mortar? It is very solid sounding (first picture)
2. How do proceed to build this up where I removed all mortar?
3. Should I use cement in the gap (vs Mortar) between the cement deck and the pool wall?
4. How to build up the wall in the front where the pebble tech was delaminated, Hydraluic Cement?
5. So water does not continue to erode the mortar What should I use to seal the crack between the existing flagstone and pool?

Pictures
1. First layer mortar
2. Gunite / Second layer Mortar
3. Gunite / Second layer mortar closer
4. Gunite - done removing mortar. also shows gap between pool wall and deck
5. Delaminated Pebbletech

Thank you
 
My gut says this might be best for a "pro' that had worked on pools before :( I don't like what my gut says so I have reached out to another person since my other reach out did not respond. There are so many factors at work here and materials that I am not sure what is best. The place the plaster is coming off is my biggest area of concern. Sorry :(
 
OK I will take a stab at it. I have done a fair amount of flagstone work on my pool. I suspect the "solid" mortar was put on the top of the bond beam after the pool was built to do a final leveling off of the bond beam. So I wouldn't remove it or if you do I would replace it and let it cure before setting the flagstone. You don't want your mortar bed between the bond beam and the bottom of the flagstone to be much thicker than 1.5"ish. Clean the area really well as well as the flagstone. if you cannot get the old mortar and grout off of the old flagstone then I would ditch it and get new. You want it to be clean so that it creates a strong bond. Use an angle grinder with a metal cement cutting disk to remove grout lines and extra mortar from the area and surrounding flagstone. You can grind the bottom of the old flagstone to clean it since you'll never see that anyways. You can also use the angle grinder to cut flagstone to size. It is pretty easy once you get the hang of it. I like to dry set all of the flagstone in the area that I am going to work on and take a pic of it. That way as I am placing it I can refer to that pic to make sure that I am getting each one correct. Clean the beam and the flagstone really well with water and a scrub brush. Get some bonding agent, I use Quikrete Concrete Bonding Adhesive. For the mortar and grout I like to use Quikrete Gray Sand/Topping Mix. It is basically portland and sand and actually mentions flagstone as one of it's uses on the bag. Both of these are available at any box shop. You can add coloring to the mortar if you choose when you mix it if your existing grout is colored. Paint bonding agent on the beam area and on the bottom of the flagstones that you are working on. I would do a small area at a time. Lay a bed of mortar on the bond beam all the way back to the deck, work it into the gap between the deck and beam and out to the edge of the pool where the plaster is and level it out. The bed should be high enough so that when you lay the flagstone on it, it would be slightly higher than the existing flagstone. Wear rubber gloves or your hands will be a mess at the end of the day. Work from one end to the other placing the flagstone in the mortar and working it down to level with the existing flagstone maintaining gaps between the Flag that mirror the gaps in your existing coping. Use a large level as you wokr to make sure that you are not deviating from the existing coping height. Use you hands to get extra mortar and smear it over the flag along the sides to grout them in place. on the front where it meets the plaster, use your finger to make that joint nice and smooth. Probably want to tape some plastic to the plaster and float the bag on the water to catch cement that oozes out into the pool. Don't worry about cleaning the top of the flag right away or the grout lines, just pack it in smooth and leave it on and keep working along. After it starts to dry come back with a large porous sponge and clean water and wipe the flag and grout lines. It is a lot like tiling if you have ever done that. Wipe the grout lines parallel to the line and then contrary to it and add more mortar and push it in if you have gaps in the grout lines. I suspect you are losing flags because your bond beam and deck react and move differently to the weather so you need to address that junction. Were it me, initially I would grout right over that area smoothly. When you are all done and it's cleaned up, let it cure for many days. Then I would come back with an angle grinder and grind out a clean straight line along the edge of the flag and deck down to bond beam. Clean it out and fill with silicone. An alternate idea would be to use something like thick cardboard to create a space along the edge of the deck and then remove that after grouting and fill with silicone after drying. In regards to any gaps or cracks between your existing coping and the plaster, if they are not overly large, I would use silicone there as well.
 
@KeithW - THANK YOU. Boy I wish I would have posted this sooner, that would have saved me a lot of time since I did remove about a 12' section of the leveling mortar

I would like to split this into two parts, P1 - Before Flagstone, P2 - Laying down flagstone
Part 1 -
1.5" Thick or less - is there a special leveling mortar or Type S what I need to use?
Do I use the bonding agent at this time?
Should I presoak the bond beam before applying the mortar
I should make the level mortar the same height approx as the existing mortar, I understand this is not critical as when I lay the stone I can make up the different
I guess I will use cardboard or something taped to the existing pebbletech to create a border for the mortar (last picture)
Mortar should be used between the bond beam and the deck, not cement

Great tip on the angle grinder thank you!

Part 2
The Flagstone has virtually no mortar on it, most of the stone I did not have to touch at all. The stone I did have to remove mortar I used the multi purpose tool
I did already dry fit, but great tip. I actually have it sitting on the deck dry fit. I will take a picture also
There is no water in the pool so I am good on that point

For the gap, there is thin piece of foam between the flagstone and the cement as seen here: Foam between paver deck and coping, and the gap is 1/2" approx, is that sufficient?

I might have some questions or need some clarifications once I complete Part 1, but I think I understand most of it.
 
If you are rebuilding the bond beam Type S is prob the best bet. Quikcrete green and white bag. But before rebuilding the beam I would want to make sure that I really needed to do that. You could measure up from the water line on the other side of the pool to the bottom of the flag. then measure up on the demo-ed side. if you are over 1.5" off then you build up.

Yes wet the bond beam and then paint on bonding agent then rebuild bond beam.

You want this to be level with the beam on the rest of the pool after you put down and level the type S.

In regards to the Pebbletech I did not address nor do I know what I would use to repair that. Were it me, I would look into buying a single bag of Pebbletech on the web. I believe that it is technically just a specialized plaster/mortar mix with pebbles in it. If you search Pebbletech repair on Amazon you will also find a number of products for that like this: Amazon.com: Pool Patch SPPP3 Sand Pebble Tec Repair Kit, 3-Pound: Garden Outdoor
 
Sounds good. I will have to add about 1.5" mortar to get to the same level as the existing flag. Okay as I am reading this...if it is 1.5" or less then slap on the mortar and call it a day, otherwise I would need to build up and then add another layer of mortar..got it.

I have already researched how to fix the pebbletec. My question was more about the edge when I am adding the mortar. This is where I will put cardboard, plastic or whatever material and then bring the mortar out to that point. Then I can fix the pebble.

Thank you very much, this has really been helpful. I will give it a shot tomorrow!
 
Hopefully tackling this Sunday. Question - The mortar behind the bond beam between beam and deck is definitely thicker that 1.5" more like 3-4". I need to replace all mortar behind the bond beam..is it okay to use mortar this thick or should I use cement?
 

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kimkats said:
I have PMed Keith and asked him to step back in on this thread. I hope he is able to help.
Click to expand...

Thank you very much!

I think it is the TYPE S mortar that that needs to be used between the bond and the deck which could be thicker than 1.5" and if I am reading correctly that is okay
If I am building up the mortar bed in areas it will be thicker than 1.5" thick - is this okay
Do I build up the mortar bed first if thicker than 1.5" and then do the second application of mortar for the flagstone?
"For the mortar and grout I like to use Quikrete Gray Sand/Topping Mix." So the same is used for laying the stone as well as the grout IF it is less than 1.5"ish, correct?

Thank you. I realize these are probably very elementary questions but this is the first time (and won't be the last as next year I will do the rest of the coping) to do anything like this.
 
troye said:
Thank you very much!

I think it is the TYPE S mortar that that needs to be used between the bond and the deck which could be thicker than 1.5" and if I am reading correctly that is okay - FIGURED IT OUT
If I am building up the mortar bed in areas it will be thicker than 1.5" thick - is this okay - YES it is okay
Do I build up the mortar bed first if thicker than 1.5" and then do the second application of mortar for the flagstone? -Yes, first type s to build up, and then the Quickrete GraySand
"For the mortar and grout I like to use Quikrete Gray Sand/Topping Mix." So the same is used for laying the stone as well as the grout IF it is less than 1.5"ish, correct? -Yup

Thank you. I realize these are probably very elementary questions but this is the first time (and won't be the last as next year I will do the rest of the coping) to do anything like this.
Click to expand...

I hope everyone enjoyed their Sunday!
 
Layman here, with only a vague recollection of hearing of the following. That last pic, is that PebbleTec running above the water line? So some of it is normally out of the water? I was told that was a no-no. Is that condoned by PebbleTec? Or was that the PB's modification? Just posing the question. If that needs to be edge tile, to future-proof it, now's the time...
 
Sorry I missed your earlier question. Yes I would use Type S in the area between the bond and the deck. Let dry and then flagstone. And yes you use the same mortar for the mortar bed and the grout. Lay your mortar bed, smooth it out, work the flagstone into it until level, then spread more mortar into the grout lines and smooth it out.
 
troye said:
@KeithW - THANK YOU. Boy I wish I would have posted this sooner, that would have saved me a lot of time since I did remove about a 12' section of the leveling mortar

I would like to split this into two parts, P1 - Before Flagstone, P2 - Laying down flagstone
Part 1 -
1.5" Thick or less - is there a special leveling mortar or Type S what I need to use?

Type S should be fine, but I'd use something stronger or add a little portland to it for anything thicker.

Do I use the bonding agent at this time?

Yes. Paint it on, or make a slurry of the bonding agent and portland cement and paint that on.

Should I presoak the bond beam before applying the mortar

The bond beam should be moist, but not have any standing water on it. I'd also dampen the coping before setting it to improve the bond.

I should make the level mortar the same height approx as the existing mortar, I understand this is not critical as when I lay the stone I can make up the different
I guess I will use cardboard or something taped to the existing pebbletech to create a border for the mortar (last picture)

You can either form it to the edge by hand, or attach a form of some type. I'd use thin plywood, or expansion joint material and either nail it on with cut nails or screw it on with tapcons rather than trying to tape on cardboard. Cardboard will deteriorate quickly from the moisture.

Great tip on the angle grinder thank you!

Part 2
The Flagstone has virtually no mortar on it, most of the stone I did not have to touch at all. The stone I did have to remove mortar I used the multi purpose tool
I did already dry fit, but great tip. I actually have it sitting on the deck dry fit. I will take a picture also
There is no water in the pool so I am good on that point

For the gap, there is thin piece of foam between the flagstone and the cement as seen here: Foam between paver deck and coping, and the gap is 1/2" approx, is that sufficient?

Yes, that's plenty.

I might have some questions or need some clarifications once I complete Part 1, but I think I understand most of it.
Click to expand...

My responses are in blue above.

troye said:
Hopefully tackling this Sunday. Question - The mortar behind the bond beam between beam and deck is definitely thicker that 1.5" more like 3-4". I need to replace all mortar behind the bond beam..is it okay to use mortar this thick or should I use cement?
Click to expand...

This is just a narrow area under the coping, between the bond beam and deck? I normally don't like using type S in thicker applications, but if I'm envisioning what you're describing correctly it shouldn't be structural, so would likely be ok. I think I'd still opt for something stronger, like standard M25 mix concrete.

Dirk said:
Layman here, with only a vague recollection of hearing of the following. That last pic, is that PebbleTec running above the water line? So some of it is normally out of the water? I was told that was a no-no. Is that condoned by PebbleTec? Or was that the PB's modification? Just posing the question. If that needs to be edge tile, to future-proof it, now's the time...
Click to expand...

It's not ideal IMO, but it's done all the time, particularly with the rolled bond beam style pools that were popular in AZ and So Cal in the 90's. They look something like this:
IMG_0790.jpg

I agree that if there's no waterline tile, now might be a good opportunity to add it.
 
Thanks gentlemen for your response. Looks like the one main thing I did wrong was not to moisten the bond beam before adding the mortar. I hope this is not a huge problem. There are a few cracks.

There is no waterline tile, that was done by the PB. Then the last person that fixed did not use PB to repair the first 4". I am on the fence if now i should go ahead and cut it out and then patch with Pool Patch

How long should let the Mortar bed dry before adding the top coat?
 
I am on the fence if now i should go ahead and cut it out and then patch with Pool Patch
Click to expand...

How long are you going to own this pool? Is this your forever house? Or are you going to be moving in a few years? I don't know what the long-term affects of pebble above the water line are. Harder to keep clean, I'd imagine. Pool plaster exposed to air? That can't be good for its longevity. What else? What benefit would the OP gain by installing the edge tile? Worth the trouble?
 
Dirk said:
How long are you going to own this pool? Is this your forever house? Or are you going to be moving in a few years? I don't know what the long-term affects of pebble above the water line are. Harder to keep clean, I'd imagine. Pool plaster exposed to air? That can't be good for its longevity. What else? What benefit would the OP gain by installing the edge tile? Worth the trouble?
Click to expand...

As for now it is our forever house but you never know. I am more concerned about the look than the functionality. Our pool is about 14 years old. the Pebble above the water line I'm not sure if it is even pebble tec. The last person who fixed the coping used some sort of pebble and it looks terrible, not even a close match.

As far as keeping clean it is not a problem. Usually I keep the water up very high so there is really nothing that is exposed
 

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