Patio Laying Questions

[DixieDeanLiverpool]

Hi all. I'm laying a patio. Relative novice, but experienced tile layer!! Hope some skills transfer.

It 22mm Indian brown mix sandstone. What depth of mortar should I use, 25, 30 or 35 mm? A wettish mix seems to be recommended. Should I use a plasticiser? Should I use a SBR bonding coat on the underside? I plan to lay using a full bed. Am I better using something like Easy Joint to joint it or a builder's sand mortar? A large area is an existing patio which had concrete slabs laid on 30mm of sand over crushed limestone. Can I lay direct onto this with the concrete or should I remove the sand and adjust the limestone with some ballast or type 1 (which)? Should the new areas just be mortar laid onto some ballast or type 1?

Lots of questions - all replies appreciated.

 

[Ian H]

When I put ours down it said a full bed of 50mm grit sand/cement. I mixed it wet with nothing added and pointed with building sand/cement that was also wet.

I'm not sure on the other questions. I put a membrane down on soil and the 50mm of mix straight onto that. It's fine a few years on except they seem to need jetwashing more regularly now.

 

[r896neo]

Remove the sand and replace it compacted type 1. Mortar straight onto the type 1.

Lay on between 25-50mm, I use about 40mm. With sandstone there is no tea bonding problems so I would say just add sbr to your mix instead, about 100ml per bag of cement. Don't lay bone dry flags on wet cement, dampen the flags if they are dry and mist throughout the day if its warm and sunny.

I prefer a good wet mix and i add plasticiser too as grit sand makes a very dead mortar so this fluffs it up a fraction. Similar consistancy to brick laying mortar.

Pointing you can use a compound or you can use mortar. Either a damp semi dry mux firmly iron and struck in or use a pointing gun and put it in wet which will give a better joint. Both can be 4:1 plastering sand :cement

 

[DixieDeanLiverpool]

r896neo Thanks for your comprehensive reply. It's much appreciated. Also, thanks to Ian H.