Vinyl Pool Coping Repair/Replacement

[DT770]

UPDATE 08/29/2023 - Check latest post for progress details

Hey TFP members,

Hoping to get some suggestions/advice regarding replacing/repairing loose natural stone coping on a steel wall vinyl liner pool. The current coping is installed in a way that seems unconventional, and using the same approach with the repair process is unlikely to bring lasting results.
As the pool was acquired with the house, there are some other unconventional methods employed by whoever was the installer, but that's a topic for another day!

For reference, we are located in a freeze-thaw climate.

Pool Details

• 2002 Build - Kidney Shape
• Steel Wall Vinyl Liner
• Plastic Steps

Coping Details

• Natural Stone on Mortar Bed
• Mortar Bed rests 50/50 on concrete (bond beam? collar?) and top of steel wall
• Diamond lath "attached" with screws to top flanges of steel wall
• Diagram attached below

Problem

• The coping is loose in many places - Repairing these segments will most likely disturb other well secured stones, so a full repair/replacement is in order.
• See attached pictures for reference.

Concern

• The coping is installed with a mortar bed applied over the concrete collar/bond beam and top flanges of the steel walls. In our situation, the concrete "collar" seems much smaller in width than what is typical. As a result, the width of the concrete is equal to less than the width of the steel wall flange, effectively halving the surface area for achieving a good bond to the coping stones in a mortar installation.
• As mortar does not form a strong bond to metal, the installer had secured diamond lath with self tapping screws to the steel wall in what I assume is an attempt to prevent the mortar bed from fracturing and crumbling due to being applied over dissimilar materials; something akin to a reinforced mortar bed. Pulling up some of the loose stones revealed that the lath is corroded and brittle, to the point where it can be easily broken without any tools and the screws no longer serving their function.
• Refer to the diagram below for a visual representation.

Spoiler: Diagram

Extra Thoughts

• Coping installations that forego mortar and instead opt for polyurethane adhesives seem to be quite common, but it doesn't seem to be a particularly long lasting solution according to some online sources and various threads here at TFP, especially in a freeze-thaw climate.
• Some detail a hybrid approach where both mortar and adhesive is used to install coping. There is a good example of this approach on Topic 3 of this Unilock Guide.
  1. An interesting solution, but I have doubts about its reliability in cases where mortar thickness exceeds 1/4", as it seems to be difficult to ensure consistent contact of the adhesive bead with a gap that large.
  2. Adds difficulty to leveling the stones due to the fast bonding nature of polyurethane adhesives, greatly reducing the amount of time any single stone can be adjusted.
• Potential case for an epoxy mortar?

I could not find any existing threads on TFP that could be of help, so any suggestions and best practices on how to tackle this are greatly appreciated!

 

[ajw22]

Nothing lasts forever outdoors. The diamond lathe buildup lasted 20 years. What length solution are you looking for? 40 years? 100 years?

I have not looked but maybe there is a synthetic version of diamond lathe that is some type of plastic or carbon fiber. The metal rusting seemed to be the weak point in the existing design.

 

[kimkats]

You have a big job ahead of you. I don't have any suggestions but am hoping to learn with you on this one.

 

[DT770]

Nothing lasts forever outdoors. The diamond lathe buildup lasted 20 years. What length solution are you looking for? 40 years? 100 years?

I have not looked but maybe there is a synthetic version of diamond lathe that is some type of plastic or carbon fiber. The metal rusting seemed to be the weak point in the existing design.

A fiberglass lath did quickly cross my mind, but I haven't looked into it yet. Will search and see if it can be a potential solution.

As for longevity, I don't know if the coping has had a total redo before, but there are signs of previous repair attempts (forgot to mention this in my post). The poor state of the coping was noted in 2020 when we first moved in.
In the attached picture, the profile of the initial mortar bed is clearly seen. Take note of the separation from both the metal flange and the stone, as well as another mortar application overtop the old mortar. This can be seen on roughly half of the pool's perimeter.

Spoiler

 

[DT770]

Took some measurements and made some changes to the diagram. Turns out there is even less adequate surface area to bond to as the concrete is 3.5" wide, while the steel flange is around 5"...
@jimmythegreek any advice?

 

[ajw22]

@jimmythegreek any advice?

He is no longer on the site.

 

[DT770]

He is no longer on the site.

Ah, was not aware of that. Anyone else I can try to ping that is knowledgeable in pool construction?

 

[ajw22]

Let's see if @AQUA~HOLICS has thoughts.

 

[AQUA~HOLICS]

Sorry but I have no experience in this area.

 

[DT770]

Looks like I may end up having to be a pioneer on this endeavor.

One small step for man, one giant leap for TFP's technical library...

 

[Newdude]

 

[kimkats]

HEY! Pass some of that over here!

 

[dleonard1122]

I see you tried pinging Jimmy for info. When I was doing my coping, I kept the following thread that he was involved in bookmarked and referenced it religiously. There's good discussion on what materials to use and how everything should be laid out. In post #81 Jimmy mentions he uses cement board (or sometimes steel mesh) on top of the steel walls to account for the thickness of the liner track. So, maybe cement board is an option for you? I ultimately didn't go that route because the steel mesh was easier to handle and cut around all of the radiused corners of the coping, but I could see over 20+ years the cement board holding up a little better.

New DIY Build Underway

A 4to5" thick form is what I use with fibermesh concrete out of a redimix truck. I make it 1.5" narrower than coping depth to account for overhang amd I dont want the deck on it I want the coping overhanging a hair on the backside over the base material so easier to screed for deck. I use...

www.troublefreepool.com

Another option comes from one of the contractors we got quotes from before we realized just how expensive it was going to be to pay someone to do it. They mentioned they use hard plastic over the steel walls. We didn't go this route so I don't have any other experience with it, and it certainly isn't TFP approved like the above info from Jimmy, but if we're looking for a material that won't degrade over time then that could be another option.

 

[DT770]

Thanks for the quick reply! I've seen Jimmy mention the cement board approach elsewhere but not in as much detail as in the thread you linked. I've read through it and bookmarked too, it's definitely a great resource.

His approach of using cement board or mesh to account for the added height of the liner track seems to be aimed at tracks that are installed proud of the steel wall top flange, which is the case with all top mount liner tracks. As our pool has a dual bead side mount liner track that is installed flush with the top of the steel wall, using cement board will result in a thick "bed" for the coping stones. This would make the joint between the track and stones 1/2" at a minimum if using 1/4" cement board and 3/4"+ if using 1/2" cement board. This method might be a feasible option, but only if we decide to relay all of the stones as relaying a section(s) would make those stones sit higher than the rest from the original install.

As for the lath method, can you describe how you installed it? Did you use fasteners to secure it or just embedded it in the mortar like a traditional reinforced floating mortar bed?
In our case, the original installation uses diamond lath secured to the steel wall with self tapping screws. I am skeptical of reusing this method as the bed visibly deflects over the steel wall when under load and all of the bearing ability is handled by the flimsy 3.5" concrete collar along with some reinforcement provided by the lath.

I wonder what the builder you asked meant by using hard plastic over the walls. I don't see how it can solve the issue as plastic is not a suitable substrate as much as metal is for cementitious mortars.

 

[dleonard1122]

Ah, yeah with a flush liner I can see how that would be an issue.

We used self-tapping screws to install the metal lathe to the tops of the steel walls. In the thread Jimmy mentioned a certain brand he liked that he recommended because they wouldn't corrode.

Your situation might be being made more difficult because of the relatively thin width of the concrete collar poured behind the lip of the steel wall. In our installation, I want to say at least half of the coping stone was supported by the concrete collar.

 

[MAPR-Austin]

Have you considered doing poured in place concrete coping? Use stainless self tapping screws and fiberglass rebar to attach to the steel panels. It is a bit more involved than setting stones, but you end up with a very strong 4"x1' concrete ribbon that is tied to the pool walls.

We have done this several times, if you're interested I can dig out some progress photos that would give your contractor some guidance.

 

[Newdude]

if you're interested I can dig out some progress photos that would give your contractor some guidance.

Teach us either way. If It doesn't help now It will for future searchers.


And DT will have a much better idea to make a well informed decision.

 

[DT770]

Ah, yeah with a flush liner I can see how that would be an issue.

We used self-tapping screws to install the metal lathe to the tops of the steel walls. In the thread Jimmy mentioned a certain brand he liked that he recommended because they wouldn't corrode.

Your situation might be being made more difficult because of the relatively thin width of the concrete collar poured behind the lip of the steel wall. In our installation, I want to say at least half of the coping stone was supported by the concrete collar.

Yes, I saw the screws recommended by Jimmy; ours seem to be zinc plated and have held up quite well, surprisingly. Your concrete definitely has adequate width, providing much more surface area to achieve a good bond. I think it would be a great retrospective for you to update the TFP community with how well your installation holds up as time goes by!

Have you considered doing poured in place concrete coping? Use stainless self tapping screws and fiberglass rebar to attach to the steel panels. It is a bit more involved than setting stones, but you end up with a very strong 4"x1' concrete ribbon that is tied to the pool walls.

We have done this several times, if you're interested I can dig out some progress photos that would give your contractor some guidance.

So like a cantilever concrete coping but one that is separate from the pool deck? Some examples would be great to see!

Personally I like how architectural concrete looks but if we were to do a 4" pour then the coping will be over an inch proud of the surrounding pavers. Perhaps that can be made to work or even slope the pour but it's something I will have to pitch to my family as we are looking to keep the natural stone.
How would self tapping screws facilitate attaching rebar? Something like using the screws to secure strapping to keep the rebar in place? Personally I would approach this with chemical anchoring.

 

[MAPR-Austin]

Correct on the cantilever coping. Chemical anchoring would also work, we are just accustomed to doweling the rebar into the shell. You can color and stamp the coping - it won't be natural stone but it also won't look like a slab out of a parking garage.

Here are some pictures of a similar project, it looks like we used regular rebar not fiber, this was done quite a while ago.

Make sure there is a suitable expansion joint material between the coping and deck, it will need to be finished with sealant.

Take extra care to protect the liner track, this pool got a new liner after the coping but there was still a little cement cream that got into the track and had to be removed.

Keep water in the pool if at all possible.

Stegmeier forms have a 3.5" finish height, so you would have a little bit of fall away from the pool. Capstone Form - Decorative Concrete Forming Systems and Deck Drains for Swimming Pools | Stegmeier LLC | 817-467-9028

 

[DT770]

A quick update on another potential method of restoring some of the stones. The idea is to use a suitable sealant (Ex: MS Polymer) to attach a tile sheet membrane to the top of the steel wall. This will provide a much better bonding surface for regular or modified mortars and is perhaps the most long term solution available without any (evident) negatives.

Correct on the cantilever coping. Chemical anchoring would also work, we are just accustomed to doweling the rebar into the shell. You can color and stamp the coping - it won't be natural stone but it also won't look like a slab out of a parking garage.

Here are some pictures of a similar project, it looks like we used regular rebar not fiber, this was done quite a while ago.

Make sure there is a suitable expansion joint material between the coping and deck, it will need to be finished with sealant.

Take extra care to protect the liner track, this pool got a new liner after the coping but there was still a little cement cream that got into the track and had to be removed.

Keep water in the pool if at all possible.

Stegmeier forms have a 3.5" finish height, so you would have a little bit of fall away from the pool. Capstone Form - Decorative Concrete Forming Systems and Deck Drains for Swimming Pools | Stegmeier LLC | 817-467-9028

Thank you for the information! I have a decent amount of concrete knowledge and everything you mentioned is indicative of a proper installation. We are unlikely to go with a concrete coping but it's great to have pointers and reference pictures.
With the Stegmeier forms, having a coping edge be 3.5" and taper to the surrounding pavers would make for an acceptable slope that wouldn't be an eye sore, at least in my opinion. Perhaps the only downside is reduced concrete strength/longevity due to the decreased thickness at the outer edge, but then again it's only subject to foot traffic.