The Brew Cabin

Posted: **Sun Aug 12, 2012 11:16 am**

Hello, I'm about to embark on a 20m2 patio of Indian sandstone, 22mm calibrated slabs in varying sizes:

900 x 600
600 x 600
600 x 295
295 x 295

I've prepared the ground and have about 80mm Type 1, compacted, and that sits in a very solid clay base.

I had planned to use Lafarge Slablayer, but can't seem to get it for love nor money. However B&Q sell a Tarmac product, Flexible Slab Fix. The instructions are the same - level to 25mm and lay the slab.

The main differences between Slablayer and the Tarmac product are that the instructions for the Tarmac one do not mention to wet the mixture, e.g. rely on natural curing over time. Both seem to be a dry mix of sand and cement.

So, I guess two questions. Firstly, if anyone has used this Tarmac stuff then would they recommend I wet the mixture? Perhaps with a fine rose head on the hose? And secondly, does anyone know if this stuff will be suitable for under the 22mm sandstone?

I can't afford to have Â£500 worth of slabs breaking when we start using the patio

Many thanks

Jim

Posted: **Sun Aug 12, 2012 11:27 am**

never heard of these products jim but they sound like something only a complete nutter would use
1 tonne of grit sand and 6 bags of cement are your friends here and a cement mixer and some hard work
read the main site for info on laying flags
LLL

Posted: **Sun Aug 12, 2012 11:43 am**

Many thanks LLL

Okay, so with a tonne of sharp sand and six bags, what sort of thickness of mix should I use under the slabs? Would 25mm be about right?

Jim

Posted: **Sun Aug 12, 2012 12:40 pm**

between 25mm and 50mm. Read the main site for a very comprehensive guide.

Here http://www.pavingexpert.com/stonpv03.htm

Posted: **Sun Aug 12, 2012 1:00 pm**

i normally aim for 35-50 mm and with your area 1 bulk bag and 6 bags of cement should achieve that
if you do 10 big shovels of sand to half a bag of cement and around 5 litres of water per mix its should work
the water content is variable according to how wet the sand is and how hot the day is,i normally aim for a mix that is wet enough to smooth flat with a towel but not sopping wet if that makes sense
LLL

Posted: **Sun Aug 12, 2012 1:38 pm**

Perfect, thank you so much for the advice. I've never used natural stone in the past, just manufactured slabs (Bradstone, Marshalls). Those patios have worked well. I'm just paranoid about the natural stone that's both thinner and more expensive

Thanks again

Jim

The Brew Cabin

Indian sandstone 22mm on tarmac flexible slab fix? - Do i or don't i....