Laying calibrated sandstone floor - advice please!

[SJRuss]

Hallo tilers!

I'm embarking on my first floor tiling project in our barn and am after a little advice!

It's 45m2 or so through hall into kitchen/diner and we've chosen to go with 25mm calibrated sandstone in one size. The overfloor is concrete - no u/f heating installed - just insulation kingspan underneath the 4ins of concrete to current b/regs.

We need to make up about a 2ins discrepancy between the original barn floor and kitchen extension so are planning to lay the sandstone on a 5:1 sand/cement mix and possibly sbr/pva the backs of the flags?

Are we on the right track do you think guys and gals? Any pointers with laying these types of flags?

Thanks in advance!

Si.

 

[SJRuss]

Anyone guys?

 

[DHTiling]

You could wetfix them..but you need to know what you are doing to use this method..

 

[Perry]

butter the backs with tile adhesive when you put them in the screed and if your screed is a less than 2"" you will have to use sbr or you could build the floor up and tile as normal

 

[White Room]

Could you not do a screed mixed with sbr and slurry the floor with 1-1 with sbr

 

[Aston]

hi

this is a tricky '1st floor tiling project' you are taking on here mate but i admire you confidence...

a few tips..

1.set out as normal but project your setting out lines up the walls where possible so you can see where you laying.
2. if 'wet bed fixing', i would personally think 4 and 1 or 5 and 1 is ideal for sandstone, just make sure you mix thouroughly an evenly using buckets to gauge your mix, not shovels. ALSO do you have any local suppliers who can deliver ready mixed s/c with a retarder in it to give you some working time? that might be a good idea labour wise?
3. make sure you give the concrete a good wetting down or it will suck the water out of your mix...if its only been recently laid then you should be fine but just test the suction.
4. use timber battens to screed off, dampen them to stop them warping
5. as whitebeam, sbr the floor prior to laying sand and cement
6. as pjc, back butter the tiles using spf BUT dont use a rapid set because it will set too early, it needs to conicide with the setting time of the sand and cement mix.
7, have a bucket of water and a brush handy to wet the back of the sandstone prior to back buttering. you can use a cement slurry mix tocoat the back of the sand stone if you dont want to use spf.
8. when tapping the back of the sandstone, dont go too mad, i would recommend using a piece of wood to distribute the impact. sandsone can break quite easily mate, so go easy!

finally, do small managable sections/bays at a time, dont over stretch yourself because your gonna get tired!!

al the best.....

 

[SJRuss]

Thanks so much for the posts so far guys! Really impressed by the knowledge base indeed!

Erk! That's a fairly sizeable task ahead then!

Okay - the choices are wet-bed laying and making up the 2" discrepancy between the 2 floors that way - leading to around a 3-3.5" bed in the deepest part [acceptable?]

Or - bring the level up so that I have a level floor throughout and lay with adhesive. Hugely expensive that way I'd have thought as the screeders will charge around 1400 pound for the 45m2 mark - plus extra 1" kingspan to bring the level up in the lower part to offset a bit of the cost of a potentially thicker screed. Or will the s/c mix be expensive in it's own right hand mixed etc?

Can't order in 45m2 of readymix as the laying will take longer than the s/c will to go off? Or were you implying that I order in the readymix to bring the level up first before wet-laying the slabs on that once it's off?

Argh! Thoughts? :mad2::mad2::mad2:

 

[Perry]

if you have the whole of the floor to build up to 2" screed it first then tile it as you will use the same amount of screed whatever you do and you would find that easer if you haven't any experience

 

[SJRuss]

Thanks fella - I would tend to agree there for sure.

So I guess get a screeding firm in to bring level up and then work my way through the tiling [daunting!] or leave the screed and get an experienced tiler instead to do the whole job using deeper s/c mix as he works through to bring level up that way?

Screed around 700 for the area needing bringing up - also been quoted 650 for a tiler to come in and do the entire job - around 15 a square metre?

 

[grumpygrouter]

Thanks fella - I would tend to agree there for sure.

So I guess get a screeding firm in to bring level up and then work my way through the tiling [daunting!] or leave the screed and get an experienced tiler instead to do the whole job using deeper s/c mix as he works through to bring level up that way?

Screed around 700 for the area needing bringing up - also been quoted 650 for a tiler to come in and do the entire job - around 15 a square metre?

This isn't the place to be discussing pricing but as a word of caution, that price given to you is extremely low for fixing natural stone......be very careful that the man is a competent tiler for this type of work and at that price!!

 

[SJRuss]

Sorry - didn't mean to bring up costs! Will bear what you've said in mind though.

I think I'm likely to try and get it laid myself - that in mind, I would say the way forward would be for me to get the level bought up with a screed, so that a least then I'm only laying a calibrated slab onto a level uniform bed of s/c. And I say 'only laying' and 'at least' with the greatest of respect for you guys of course! Thinking about the job - I suddenly can't breathe too well!

Previous posts suggest laying into wet-bed with a spf? What does that stand for - an adhesive? Why would I need to do that? Too seal the slab to stop colour of cement penetrating? :dizzy2:

By the way - these slabs are 25-30mm EXTERNAL slabs with a riven surface - not actually internal sandstone tiles as such - just for your reference!

 

[Perry]

spf single part flexible adhesive it helps it stick like s**t to a blanket but if you are screeding it first it i would still back butter the tiles with adhesive will help getting a solid bed

 

[SJRuss]

Thanks for the post.

I have to admit to being a little confused now. If I screed to bring the level up, it'll only be in the area that actually needs bringing up - so I'd have 2 different surfaces on which to lay the stone - concrete and screed finish.

Regardless of the surface - I'll still have to bed them down on wet s/c as they are heavy external slabs surely? Are you suggesting that I also butter the back of the slabs as well with spf too?

Argh! :smilewinkgrin:

 

[Aston]

whats the difference of floor depth at the highest point of the floor mate??

you say theres a 2 inch difference at the lowest point but whats the approx depth of the highest?? if its only a few mill then that rules out doing a sand and cement screed.

the most cost effective way to tile the floor would be to wet fix the slabs as above, but the term wet fix doesent actually mean its a very wet mix ie like mortar, its a firmer mix and the use of spf adhesive is the give the slabs extra bond when it makes contact with the sand and cement..

my honest advice would be to get a tiler to give you a price to do the job, i am sure theres plenty on here who are local to you, if you are from the merseyside area , then i'd be happy to come and see you :0) .as i said above, its a difficult first task and it might be the wisest thing you could do in the long term...

 

[Ken Bruty]

Yoiks:yikes: £15/m2, BE VERY CAREFUL!!