My first Shotcrete pool

Well, we've officially started our first shotcrete pool. We are mainly a vinyl liner company, but a hot tub customer of ours owns a concrete company and decided to build himself a shotcrete pool. Noone within a few hundred miles builds shotcrete or gunite pools, so we're on our own.
The pool is 20' X 40' freeform with a bench and steps, 2 skimmers on 2" lines, 4 looped returns on 2" lines and 2 main drains sharing a 2" line. The pump is a Jandy Stealth 1 HP, Jandy CL580 Cartridge Filter, Jandy AE3000T Heat Pump, Jandy AquaPure SWG w/ PDA, 600 sq. ft. flagstone decking, diving rock, and built in bbq.
We've got the excavation, steel (#5 rebar installed on 8" centers, with a 20" deep beam with 6 #5 bars all around the pool) and initial plumbing done. They are shooting the shell tomorrow. Being a vinyl installer there are a couple things that I do not know, and I am hoping someone here can help me. When laying the flagstone decking, is it mortared onto the top of the pool. The flagstone is 2" thick and will be dry-set on tamped crushed gravel. Also, should there be any kind of expansion joint between the 6" tiles and the flagstone coping.

Thanks for the help.

Brad
Waterworks Pools

After the shotcrete, level out the face and top of the bond beam with a brown coat. This will make the tile and stone installation easier. Install the flag stone on the bond beam with type s mortar. Try to keep the flagstone grout joints tight, wide joints tend to develop cracks. Try to keep your flagstone over hang no less than 1 1/2", this will help hide the natural uneveness of the flagstone at the tile line. The gap between the tile and flagstone gets grouted.

Hope this helps.

Hi, Brad and "Fig"

Fig, you obviously know your stuff.......If I understand you correctly, you're saying to tie the deck (flagstone) to the bond beam with mortar. When I built my one and only pool, ("rookie" written all over me) my pool guru had me seperate the decking completely from the beam with a layer of roofing felt. (could've been any material....just make sure there was no masonry connection)

His thinking was that the pool wall and decking expand in different directions and any masonry bond would crack. The gap between these two surfaces (caused by the roofing felt) was then sealed with polyurethane cauling to provide a flexible, waterproof bond allowing the wall and decking to do there thing.

Was that a bogus idea or have I completely misinterpreted your post? :)

You do not want to tie the pool coping to the pool deck. Keep the flagstone coping over-hang over the bond beam on the deck side to a minimum because the pool and the ground around it will move at a different rate when the temperatures change. On the back of the bond beam coping flagstone install Poli-Void roll foam then install the deck stone. Then zip the top of the foam off (instructions come with the Poli-Void), fill the gap with a caulk that will match the color of the grout used for the stone on the deck. While the caulk is still wet then apply sand on it to match the color of the sand in the stone grout (the idea is to make the caulk and sand look like the mortar between the stone work). Nothing ruins the look of a good stone job than to have a caulk joint that does not match the surrounding material.

Thanks Fig and Duraleigh. I'm just trying to get this straight. Basically, I'm going to cut my flagstone so that the deck-side of the stone is fairly even with the back of the beam all the way around the pool. Then I add poly-void to the back and grout on the top. Then install my decking.
Does anything change because the deck is dry-set and will not be on a concrete base and also not mortared or grouted in?

Brad
Waterworks

Hi, Brad,

As posted, I am a rookie on this but I do understand the principle. That is, put some type of flexible connection between the pool wall and the decking....otherwise, it will crack.

So, since your drysetting, it makes sense to me that your flexible connection will take place automatically because you do not intend to mortar the joints.

I understand what fig is saying by mortaring the first row or coping to the bond beam....that makes sense, too. That would mean to me an expansion joint between the flagstone coping and waterline tile is unnecessary and not workable anyway.

If we're all on the same page, it would then seem logical to me that it is not necessary to use polyvoid since you are using no grout on the remainder of the decking material.

I'm on fairly thin ice and fig understands this better than me. I did a poured concrete decking....as you said..different animal.:)

I was thinking the same thing. If my deck won't be anchored to anything than I shouldn't need an expansion joint and the individual stones can move on their own. And the coping pieces would need to be mortared down because otherwise they could just topple into the pool. Thanks

Brad

If your going to just put sand between the deck stones then you will not need the caulk. Two things to think about though, one don't let the deck stones touch the pool coping stones and two if you are doing a sand set on the deck stones and water is allowed to to drain down between the coping stone and the deck stone then make sure the water will drain away from the bond beam of the pool (this is important if you live in an area that has freezing weather). If you are going to mortar between the stones on the sand base then you will need to caulk between the coping stone and the deck because you do not want a void space and you do not want mortar between them. Hope this helps.

That's great Fig, I appreciate the help. Once we're all done I'll post some pictures.

Brad