How to keep flagstone from flaking off

[trs]

I have a flagstone deck around a pool, and over time the flagstone has begun to flake off in thin layers.  By tapping on some of the flagstone pavers, you can tell that on a few pavers, there are stone layers are in a sense de-laminating, and soon will flake off.  I have used general stone sealers to minimize water infiltration, but this has not solved the problem.  Is there any type of epoxy that can be used on flagstone which will soak down into the stone and pretty much bond the loose layers together?  Any thoughts out there?  Thanks

[Mark D.]

I have discussed your problem with glue manufacturers and there are definite problems with using epoxy for this application. You could use a penetrating epoxy, and if you got it into the parts which are separating it would hold those parts together, but if the stone is starting to come apart there are other sections which will follow. If you saturated the whole thing in penetrating epoxy that would work, at least for awhile, but then you have the problem that you now have a gloss on your stone and the glue seals it so it is not going to breathe. When moisture condenses under that seal it will give a white hue to the stone until it has evaporated out the way it came in. Penetrating epoxy has no viscosity. It has the consistency of water until it starts to gel.

The best result would be to use a product by Tenax called Petrolux, which is basically a lacquer. It will still affect the shine and will probably give your stone the wet look, but it will breathe where the epoxy won't.

I am still awaiting more information as there is a worldwide stone show going on in Italy this week and all the people I would call on are there.

Mark

[trs]

Mark, thankyou for looking into this for me.  Please let me know if you find out anything more on what I could use.  The Petrolux product you mentioned, would this be more along the lines of a stone sealer than a glue?  Also, if I end up having to stick with the stone sealer approach, is there a recommended sealer?  Thankyou again.

[Mark D.]

There is a sealer by Tenax called Protex. This is a resin based sealer and after 2-3 applications it will have penetrated and sealed the stone so the weather won't affect it and will help prevent further flaking. It is not a glue, it will not bond it all together. You should chip off any loose pieces and clean it thoroughly before you use this. Wipe it on and wipe it off (to remove film). Wait 20 minutes between applications. This product will help prevent further flaking, but again this is not a permanent solution.

It is natural for flagstone to flake as it is a sedimentary stone. The only way to permanently prevent this would be to impregnate the stone with an epoxy resin. This would change the color & the gloss and there is no way to fully polish it off unless you honed the entire deck level first.

Mark