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Posted: Tue Jun 27, 2006 11:46 am
by buk
If I lay 10 mm thick (thin) slate (riven front, machined back) on a patio in the UK, the results are going to be:
a) Enevitable?
b) A disaster?
c) Fine, so long as you seal it.
d) Fine, so long as you don't walk on it it, or have a frost, or...
e) Other?
What if 4 x 300 square tiles were laid on top of 600x600x50 concrete pavers?
How? Tile adhesive & grout?
Or is the whole idea to stupid for words?
Posted: Sun Jul 02, 2006 11:59 pm
by buk
Could someone explain what a "very stiff" means in the following:
"Lay on 35-50mm of a very stiff Class IV mortar over a prepared base or sub-base".
Also, is "Granolithic mortar" made with sub 10 mm aggregate a suitable alternative for this application? (I'm trying to save some cash, but not if it is not safe.
Looking around at various suppliers (on the suppliers page) of slate paving suitable for external pedestrian/patio use, many of them offer 10 mm & 12mm thick products for this purpose. The only remaining question is whether the product in question is of a suitable grade--the prospective supplier claims it is, but won't make guarentees because of "the risk of poor installation". Several of the reputable supppliers listed here will likewise make no guarentee for similar reasons.
The problem I have is that the supplier I am considering is cheaper than most others, mostly because they are local which means I avoid transport costs. (I can fetch the tiles in two or three trips in my own car rather than paying £45-180+ quoted by other suppliers.).
So, how do I determine if this particular batch of chinese slate tiles are up to the job? I ask, they say sure, but you gotta seal them. Looking around, the sealing is to prevent staning from spills rather than prevention of delimination as warned about on the slate page of the main website:
Some of the slate products sold as suitable for patio or pavement construction are actually internal flooring grade tiles, totally unsuitable for the soggy British climate and likely to delaminate with the first serious frost. So make sure any imported slate is guaranteed to be suitable for external use.
How can I independantly verify the supplier assertion?
Cheers, Buk.
Ps. Sorry to push, but the low price is likely to end any time soon.
Posted: Sun Jul 09, 2006 12:15 pm
by Tony McC
"Very stiff" means minimal added water - just enough water to bind everything together.
Granolithic isn;t available in 10mm. It's 6mm to dust and is more expensive per cubic metre (or barrowful) than a 'normal' concrete or mortar.
I can't comment on the viability of your Chinese Slate. There's good stuff and there's crap. There's stuff that delaminates after a shower of rain, and there's stuff that is as hard as nails. How you tell the difference is something that comes with experience - price is not always the best guide to suitability.
All I can suggest is that you use a reputable supplier, such as Midland Slate & Tile, Rock Unique, Silverland Stone, Global Stone/Kent Blaxill, rather than some small trader or garden centre. Generally speaking, these more reputable traders are more willing to exchange sub-standard product on the very rare occasions it escapes their notice and makes it out into the big wide world.