I think I've been very stupid

[Sulphurman]

Dear Tiling forum,

I hope you can help - I'm one of those blokes who decides to completely renovate a house with not an enormous amount of experience...although I've done 4 now so I should really know better.

I've bought some calibrated limestone flags, 22mm thick, 600mm x free length. Some to lay in the kitchen and some to lay on the patio. They all look fairly similar but the patio ones are not so polished. The missus is looking forward to a good looking job but I'm now worried.

I have done a few tiling jobs before and I am slow and methodical and the jobs have looked very good when complete. This is a big job, about 40M2 inside and 22M2 outside, I've not laid flags before but hard work doesn't faze me.

The kitchen floor is still to have the insulation/wet underfloor heating/ screed, so the level and adhesive bed+tile thickness is still determinable. However, outside I think I might have messed it right up. I've laid a very flat screeded slab (to the correct fall) with some ronafix and fibres in it, with about 6mm or so allowance for adhesive. I now think I might've got this monumentally wrong. Can anybody offer me some advice please? I need the flags to butt up level to a cast iron drain grill thingy that runs along by some doors. I was assuming that I could use a thin adhesive both inside and out, but I'm now reading about de-coupling mats and seeing people talk about beds of 30mm.

Feeling like a right donut :-( or am I worrying unduly?

Any advice very much appreciated and apologies for the 1st post being the "help, I'm an idiot" type. Thanks.

 

[Ajax123]

assuming you use an adhesive suitable for outdoors I see no reason why a thin bed addy will not be ok. When I did my quarry tile path a few years back I used a standard set flexible adhesive from Ultra I think it was. fast tillers use rapid set as they can grout same day and theres less chance of the kids walking on the tiles and moving them. I used standard set as it gave me time to work as like you I am quite slow at tiling.

 

[One Day]

Nice thick chunky stone on a well prepared slab with adequate drainage... I'd say usual thin bed (but solid bed) will be fine. Try BAL stone and tile ptb.
Thinner stone, I'd want to use ditra or even ditra-drain.

 

[Rich Midge]

Ultra ProFlex ES or Setaflex Standard Set are both good externally and can be bedded down to 3mm. Rapid may be the way to go through if the you're planning on tiling it before the spring.

 

[Rich Midge]

Nice thick chunky stone on a well prepared slab with adequate drainage... I'd say usual thin bed (but solid bed) will be fine. Try BAL stone and tile ptb.
Thinner stone, I'd want to use ditra or even ditra-drain.

Is there a minimum depth with Bal ptb?

 

[Sulphurman]

Wow, thanks Ajax, Impish and Midge, I'm breathing a sigh of relief as I type! Thank you very much for the speed of the replies too.

Could I be really cheeky and ask for some advice on the interior as well? I've been told by the stone merchant that if I'm having underfloor heating I'll need a de-coupling mat, but I'm a bit concerned as to how thick the bed needs to be under the flags. I have never had to tile over a heated floor before but I'm guessing if the bed was too thin it wouldn't work so well?

I get the idea in theory, differing layers may heat and cool at differing rates! Also haven't a clue about putting in expansion joints.

Thanks again. What a top community!

 

[Rich Midge]

I'd wait for @Ajax123 to get back to you re the screed, ufh etc internally. Personally I always decouple over a heated screed if fitting stone. You'll find plenty of threads on here regarding the correct prep, drying times etc. You may want to pm Ajax as I'm pretty sure he could possibly even sort the screed out for you or will certainly point you in the right direction.

 

[Tile Shop]

Is there a minimum depth with Bal ptb?

Minimum 3mm, maximum 25mm

 

[Sulphurman]

Hello again, can I ask, what should I allow in mm for the ditra mat and adhesive? I'm trying to work out my levels.

I've got 22mm approx calibrated stone flags and need to get my finished floor level exactly right.

Also can you advise on what to use below the mat and above it please? The screed will have ronafix and fibres in it, like the outside slab.

Also!! Can I put expansion joints in the screed, then put the dirt mat straight over the top, or is that a no-no?

Cheers in advance

 

[Tile Shop]

4mm...... 3 for ditra and 1 for the addy..... providing the floor is dead flat.

 

[J Sid]

4mm and 4mm for me

 

[Ajax123]

sorry.. missed this one. decoupling is a must with soft stone over heated screed. british stone federation recomendation.

 

[Sulphurman]

Thanks very much. So I'm looking at about 6mm allowance? Maybe up to 8mm if floor is a bit uneven?

I'd really like your opinions on the way to go over expansion joints in the screed please. I want the stone to just flow through the room space but it's a bit of a funny shape here and there....not sure if I even need any joints.

Will try uploading a plan.

Thanks again for your combined experience.