Loose, separated, and cracking flagstone on my hot tub - how best to repair

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FortWorthAreaPool

0
Jun 27, 2014
4
Ft Worth, Texas
Hello - first time poster here,

I have a hot tub that has two waterfalls into my pool. The white flagstone (don't know how better to describe it) is cracking in places, loose in places, and has come off in places.

I have read this thread: http://www.troublefreepool.com/threads/29997-Loose-Flagstone-Coping
I have three questions:
1. in the post 05-09-2011, 01:00 PM in the thread I referenced above, it mentions "TypeS mortar with a bonding agent." I bought some Type S mortar. Do I need to buy bonding agent as well (if so, where to buy and what's it called) or is the bonding agent just a part of the Type S mortar, so there's nothing else to buy?
2. As I mentioned, I also have some stones on the top of the hot tub that seem secure but have some cracks. Is there some sort of sealant that I should put in the cracks (they are narrow, so this task would be difficult), or is there some sealing finish (same idea as using polyurethane to seal a wood floor but I certainly don't want something that slick on the hot tub) that I could coat the entire top of the hot tub with?
3. Any other tips or direction?

I am planning to remove any stones that I can wiggle loose with my hands, clean off the grout, wet the surfaces and re-seat the stones, let it dry, fill in grout, then maybe seal the grout and or stone based upon recommendations here. Please see pictures below.

ht1.jpg
ht2.jpg
ht3.jpg


thanks!
FortWorthAreaPool (how about "FW" for short?)
 
Welcome to TFP FW! :wave:

Although I can't help you with this issue you're having, I just wanted to welcome you. You have a very nice looking pool and I hope you can get those stones fixed right up. :goodjob: You've come to the best pool forum on the web! :cool: Hope you enjoy your stay here with us!
 
Hey Fort Worth,

So I don't KNOW that this is the case but a quick google search turned up that bonding agent is an additive for concrete because I kept encountering people asking how much to add.

A search of home depot.com for "bonding agent" yielded an entire concrete bonding agent section. Here's an example, http://www.homedepot.com/p/Quikrete-1-gal-Concrete-Bonding-Adhesive-990201/100318465

I know that they ARE stone and grout sealants but I don't have enough experience to be able to tell you which one is good or suitable for your project. Sorry I couldn't be of more help. Maybe someone will be along shortly to answer the rest.
 
Thanks, Blueskies,
I looked at the bonding agent link and found two potential applications. If you have an opinion over which to use, please advise. Or whoever replies next, please feel free to advise. I could see either painting it on and letting it dry before seating or mixing it in with the mortar as what seem to be logical options.

"APPLICATIONS
Use As a Paint-On Adhesive
• Apply to surface with brush, roller or spray to the thickness of a coat
of paint. Can be applied to a dry or damp surface
• Place new concrete, topping mixes, Portland cement, plaster mixes
or patches as soon as the adhesive
is dry. Gypsum plasters and fin-
ish plaster should be placed over tacky coat of adhesive
• Make sure basecoat plaster is dry before applying adhesive
• Tools, brushes and other application accessories should be
immediately cleaned with water. Use hot water to clean up any
drippings
Use As a Slurry Coat
• Make slurry from approximately 2 parts cement and 1 part Concrete
Bonding Adhesive
• Apply a thin layer of slurry onto the properly prepared substrate
using a trowel, brush or squeegee, being sure to rub the slurry
thoroughly into the surface
• Apply topping or repair material immediately before the slurry dries"

thanks!
 
Well, nothing fell on the hot tub, and no one took a hammer to it if that's what you're asking.
I assume that over 15+ years the rain and sun and cold and heat separated the joints between the rock and mortar. Then more rain made it worse until some rocks became loose. Then when I noticed that they were loose, I wiggled them free by hand rather than leaving them loose where someone might step or lean on them only to have them give way.
 
Interesting, they look a little more recent than that but I think that you "loosened them up" probably accounts for that.

Those masonry joints come loose usually for one of two reasons......

1. Improper bonding at time of installation

2. Moisture penetrates down into the joint and then the freeze-that cycle pops them loose.

The fix may not be as easy as it appears. I would consider getting a professional estimate first and the going from there.

My success with masonry repairs has been OK but incredibly time consuming to get it looking really good.
 
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