Mate and I have just laid our patio (never done one before), and although it looks great, I left it for three days to go off and upon checking the smaller (300x300) slabs can be lifted fairly easily if you put a finger around the edge! I'm guessing the larger ones are only held down by weight so was it just that the mortar mix wasn't strong enough or what?!
We went for a roughly 4 or 5:1 fairly dry mix under indian sandstone. He's done some building and out of a ton bag of sharp sand was roughly working it out as half a bag of cement to about 10 shovels to get the 5:1 as he said that was about right so I just took his word for it. Has he gotten the measurements massively wrong??
The issue is the dry mix. The bedding mix needs to have some water in it to help it bond to the underside of the stone. Its also worth adding SBR in to mortar mix as this will further strengthen the bond
Yes what Steve said,dry mix without SBR fails for most indian stone, if they are not rocking it may last a little while but will fail in due course
LLL
Thanks for the replies, having another crack at it this weekend with a much wetter mix to get the suction. Just trying to decide what the best method to joint is... old fashioned 3:1 mortar and a bit of graft, or one of the brush in pot type type products, and even then, which one?!
