Indian Sandstone and Slurry Primer

[Jever]

Hi all,

I'm planning to lay an indian sandstone patio soon and have been doing some research.

It appears that the professionals coat the backs of the stones with a slurry primer just before they lay them, which improves the bond with the underlying cement and therefore prevents the pointing from failing.

I've seen this product mentioned:

Everbuild 503 Premium SBR Bond Bonding Agent

Reduce cracking and shrinking when mortaring with this SBR bonding agent from Everbuild. It’s great for waterproofing outside areas that are liable to be damp, humid or continuously exposed to water or steam. Use it as a bonding agent, primer, sealer and admixture for renderings and floor...

www.toolstation.com

but this appears to be a cement additive, rather than being applied directly to the back of the stones. If it's an additive, how much should I put in with each mix?

Does anyone know any slurry product that goes directly on the back of the stones?

Thanks in advance

Jever

 

[imroberts]

I've been looking at porcelain paving for which I understand a slurry primer is absolutely crucial.

This is one such example, from my own research this is one of the most common / well regarded:

Pavestone Priming Slurry - 12.5kg Tub

Pavestone Priming Slurry 12.5 KG Tub Approximately 15m² per 12.5kg tub. A key characteristic of porcelain is an exceptionally low water absorption value, meaning that the paving tile will not draw moisture to the same degree as other paving materials. This is a great benefit when it come to...

www.pavingdirect.com

With this product you apparently mix the slurry primer and apply this to the back of the slab at 1-2mm thick. This bonds to the back of the slab and also to the concrete base when you lay the slabs.

I can't comment on Indian sandstone but if a slurry primer is required I would expect it to be a similar product and process.