Limestone Slabs advice

[engineer21]

Hi guys, first time here and pleased ive found somewhere i think i will get good advice

ive bought some black limestone slabs 20mm ish think, these are to be laid over my existing front steps to house.

as my existing front steps are concrete what can i use to stick the slabs with? both vertical and horizontal.

i realise digging out the steps and starting again is prob the most professional way but really not what i want to do.

should i use something like tilers adhesive? or would something like no more nails etc work best? bear in mind its external and for a front door.

also what is best to grout the joints? and how big a gap should i be leaving?

thanks any advice appreciated

 

[Flintstone]

Get a good quality tile adhesive, s1 or s2 rated, slow setting probably best for you. Make sure the steps are clean of any debris, prime the step with acrylic primer as per instructions and tile it making sure you get a solid bed of adhesive, not dabs!

 

[Martyn Leeds]

I reckon 'no more nails' or a similar product might just do the job, definitely worth a try.

I need to stop drinking on a Monday morning, anyway, i'm off to the pizza shop to ask them for fish & chips..

 

[engineer21]

i didnt think anything from a tube would be popular round here!

but been told by my local diy shops to lay sand and cement....i also know that wont last in a thin bed

cheers local tiler will look for some of that

 

[One Day]

If you want the black limestone to stay black, then you also need to consider that water sat under the stone, or saturated in the adhesive bed will likely lead to effloresence.
It would be worthwhile using a product like Ditra-drain on the existing steps before fixing the stone.
It will add another layer (and expense) but will greatly aid drainage beneath the stone.

 

[One Day]

This is worth a read: Pavingexpert - The Curse of Black Limestone - http://www.pavingexpert.com/stonpv05.htm