Quarry tiles, lime mortar and earth...is that right?

[zelichops]

Hi, can anyone out there confirm for me that I can use 3.5NHL lime mortar to lay reclaimed quarry tiles onto the earth base I discovered beneath an area of concrete we have had to take up when redoing the kitchen. The earth does not seem to be as solid as I would have thought necessary to lay anything and I can't work out how the mortar will bond with it to make the tiles secure. The rest of the room has quarry tiles laid on lime and ash or at least that's what I think it is.

There is also very little gap between the tiles and it would be great if anyone has thoughts on what to use as grout. Looking around the forums I have picked out silver sand and lime mix as an option but does that really stand up to mopping, sweeping etc?

 

[plasticpigeon]

I've just done this job, laying quarries in my kitchen with minimal gaps. I used NHL5 and sharp sand mortar on top of a 100mm limecrete slab. I'd have thought it would have been ok to lay on earth as that is quite a traditional way to do things, but I imagine there is more risk of the tiles moving a bit. Also I bought some stuff that is a lime based grout from ty mawr, which seems to be lime and a very fine aggregate, much finer than silver sand. it needs to be mixed up and used to point the gaps. Brushing it in and watering (if you were considering this) doesn't seem to work very well. Where are you located. I have lots of NHL5 to give away!!!

 

[zelichops]

Sorry for the delay but thanks for your reply. Just have a couple (well a lot) of things I'm unsure about as it's my first time of using lime mortar; do you use the mix dry, how long before it can be walked on, and do you have to take into account any "settling" whilst it's going off to ensure it's level with the rest of the floor. We would really appreciate any direction you can give. I also understand from other posts that the tiles should be cleaned before the old grout is removed and redone, then they can be sealed, have I got that right? We're based in the High Peak, Derbyshire so probably not practical to take you up on your kind offer, but Thanks anyway.

 

[MatthewC]

You need to lay a decent bed of NHL (I used 5) in a wet mix with sharp sand - ideally first lay a 100mm slab with aggregate/LECA/RFG and then (later) a 50-75mm bed of NHL/sand only. It doesn't need to bind on the earth, it'll make a solid bed of its own so long as the area is large enough. Ours didn't settle much, but you correct that when you lay the bed and set the tiles on that. See my blog in May 2011 (click the blue spot on right) for more details of the limecrete floor we laid.