Laying natural sandstone paving slabs

[jb1468]

Bit of advice before I commence the job, hoping to avoid any pitfalls and tips welcome.

Bought in B&Q (says sourced from India) 20mm thick. Needed a thinner stone to allow gate to open when laid. Not a large job - 6 Square metres (path to door). Will be using an edging to separate path and decorative stones.

I have never laid such a product, however I have laid standard slabs a few times and done tiled floors dozen of times so I think I should be OK skill wise. It's been a few years mind since I worked with slabs. Will need to cut several of them (all straight cuts) and plan to use an angle grinder as I have one (trying to keep costs down)

Base is concrete (clean and solid). Questions is around adhesive and grout. I plan to use a mortar mix. Any issues with this? What would be the best ratio mix of sand/cement? Do I need to dampen the concrete base or slab when laying?

I assume I need to use a sealer before grouting?

Do I just use mortar again or should I be looking into an outdoor grout? I am worried about staining the stone during grouting. How best to avoid this or clean up from it?

If worst happens and it does stain can it be buffed out later?

Appreciate any help or advice offered

 

[mikeey84]

Best tip for working with sandstone in my experience is get some sdr and make a cement slurry to paint the underside with prior to laying.

Helps them stick and helps prevent staining coming through

 

[HERTS P&D]

https://www.pavingexpert.com/sbr_01

Andy

 

[jb1468]

On reflection maybe for such a small area its better to use an exterior stone adhesive from the likes of Mapei?

 

[mikeey84]

You can get small tubs of sbr from wickes rather than a big 5l bottle

 

[jb1468]

You can get small tubs of sbr from wickes rather than a big 5l bottle

Cheers in Northern Ireland - no Wickes. Might be able to get smaller quantities in builders merchants local. Still weighing up which product to use.

 

[mikeey84]

Ah, fair enough. A proprietary version maybe a better idea!

 

[jb1468]

Any reason why I can't use Bal rapid flex one adhesive to lay these sandstone 20mm thick stones onto a concrete base. From my reading it seems to suggest it is suitable.