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Posted: Thu Sep 02, 2010 8:09 pm
by kristy22
A patio was laid nearly one year ago in Fossil Mint Indian Sandstone. Some of the slabs are flaking. Is it frost damage? What should I do? Apply a sealant and if so, any recommendations please.
Posted: Fri Sep 03, 2010 9:51 am
by Tony McC
Fossil Mint is probably the softest and least suitable of the imported stones, but people love it for reasons that escape me completely.
Sealants won't fix the delamination or prevent any further occurrences. You may find that the flaking, as you call it, reaches a point where no more occurs, but that can't be guaranteed. The only viable alternative is to replace the worst affected flags with ones that seem to be less prone to the problem.
Posted: Fri Sep 03, 2010 1:59 pm
by jonnyboyentire
The only sealant that may help is one which actually permeates into the molecular structure of the stone. It will get into the microscopic voids and does help to bonds them together. Depends how bad it is I suppose. I can point you in the right direction for the sealant 
but be warned it is not cheap like the £40 quid b&q stuff!
How big an area?
Posted: Fri Sep 03, 2010 6:26 pm
by kristy22
Thank you Tony Mc C and jonnyboyentire for your replies. There is a single garage driveway with a concrete base at the front and patio at the back. I wish that I had known it was the softest before buying it. I think it would be difficult to replace the slabs. Interested in the name of the sealant please, jonnyboyentire. Also, please, what would you clean the stones with as they are barely a year old but suffer from premature ageing.
Posted: Fri Sep 03, 2010 8:21 pm
by pickwell paving
soapy water and a stiff brush or i know someone who swears by jeyes fluid but have never tried it personally, try it on a spare slab if you have one or in an inconspicuous area, nothing acidic on indian stone and if the slabs are delaminating i wouldn't use a pressure washer.
Posted: Fri Sep 03, 2010 9:17 pm
by lutonlagerlout
i too am interested in the sealant that works on a molecular level johnny :;):
would like to see the data sheet on that one
as said kristy sealants wont stop de lamination
a photo would be handy
cheers LLL 
Posted: Sat Sep 04, 2010 10:38 am
by Tony McC
I still don't think a sealant can arrest delamination. I know some decorative 'flaky' stones are held together by an epoxy resin injected under pressure, but the cost is unrealistic for this type of project, where the stone is essentially worthless.
I looked at having a 330kg piece of stone treated with the resin so that we could use it for my Dad's headstone, and it was going to cost around 5,000 Euro, including the transport to-and-from the factory in Italy plus VAT, etc. That's roughly 15 Euro per kg of stone. A 560x560x22mm Fossil Mint flagstone weighs around 19kg. So on that basis, it would cost 285 Euro (240 quid) to impregnate with resin, whereas a new flagstone costs around 7 quid.
Posted: Sat Sep 04, 2010 11:41 am
by kristy22
That sealant sounds really expensive 
!! Shall try the Jeyes fluid. What causes the delamination??? Shall try posting a pic. Sounds all.
Posted: Sat Sep 04, 2010 11:42 am
by kristy22
Sorry, sorry, meant to say Thanks all:laugh:
Posted: Sat Sep 04, 2010 12:33 pm
by Bob_A
A year old is still relatively new could it be that the stuff that is flaking off is just loose bits?
Perhaps once all those bits have gone you'll be left with something more solid?
This is more of a question rather than a diagnosis.
What is the jeyes fluid meant to do?
Posted: Sat Sep 04, 2010 12:47 pm
by Tony McC
Jeyes Fluid is handy for killing off moss, but it will do bugger all about the delamination!
Posted: Sat Sep 04, 2010 1:19 pm
by lutonlagerlout
jeyes is very toxic
IIRC they can no longer state it is a pesticide (EU rules) but we use it at the allotments for just that
LLL
Posted: Sat Sep 04, 2010 3:06 pm
by kristy22
Thank you Bob_S. The stone is flaking in sheets, rather than loose bits. Maybe it was the cold last winter but if it happens again this winter, the stone is going to get thinner and thinner. Would the sealant stop the flaking???? Shall try the Jeyes fluid on the pointing. Still looking for the name of a suitable sealant. Any advice please??? I feel over this problem.
Posted: Tue Sep 14, 2010 12:26 am
by lutonlagerlout
the construction of the paving looks a fair job from where i am sitting, looks like someone has been playing around with 1 of those 40 quid karchers (fail)
IMHO the stone was probably not the finest and the cold winter has found it out
i would use a weak bleach solution on the flags before any more cleaning efforts
no point at all sealing
LLL
