DIY Related: Why FLEXIBLE adhesive / grout?

[zygo]

I have posted (elsewhere on this forum) a project to tile a small room in granite. The subfloor is about 80mm sand/cement mix laid on 80mm Celcon insulation board, laid on DPC placed over an existing concrete garage floor (probably 100mm deep).

I plan to use Mapei grout and adhesive (after laying a screed on a primer). I think the adhesive and grout come in quick set and standard set (I'm a slow and fussy DIYer, so I'll be using the standard set type), and also in flexible and ... rigid/hard(?). I am advised to use 3mm spacers.

Given the sub-structure, which would a professional use? And why?

Thanks everyone. Of all the forums I've visited on this project for different trades, this is easily the most helpful.
Z

[GazTech]

HI zygo,
These days most pro's would opt for the flexible type adhesives and grouts. Mainly there being little in price difference and the peace of mind that they have chosen to go above the normal spec.....Gaz

[zygo]

Thanks GazTeck. that was fast!

I didn't know there was a price difference or that one was better than the other - I just thought they were suited for different applications. Maybe I should ask: If flexible products are the norm, when would a pro avoid flexible and insist on the hard set type?Perhaps the answer's 'never'. I guess there's always a chance of some movement even in a concrete floor, due to different rates of expansion and contraction so flexible allows for this without cracking and loosening the tiles. Would that be it?

BTW Is Kerra-quick a fast-setting adhesive - the name suggests it is. If so, what's the slow set type called? Kerra-slow?????

Z

[GazTech]

Thanks GazTeck. that was fast!

I didn't know there was a price difference or that one was better than the other - I just thought they were suited for different applications. Maybe I should ask: If flexible products are the norm, when would a pro avoid flexible and insist on the hard set type?Perhaps the answer's 'never'. I guess there's always a chance of some movement even in a concrete floor, due to different rates of expansion and contraction so flexible allows for this without cracking and loosening the tiles. Would that be it?

BTW Is Kerra-quick a fast-setting adhesive - the name suggests it is. If so, what's the slow set type called? Kerra-slow?????

Z

....being from Bal I couldn't possibly comment on Mapei products.....

[grumpygrouter]

Thanks GazTeck. that was fast!

I didn't know there was a price difference or that one was better than the other - I just thought they were suited for different applications. Maybe I should ask: If flexible products are the norm, when would a pro avoid flexible and insist on the hard set type?Perhaps the answer's 'never'. I guess there's always a chance of some movement even in a concrete floor, due to different rates of expansion and contraction so flexible allows for this without cracking and loosening the tiles. Would that be it?

BTW Is Kerra-quick a fast-setting adhesive - the name suggests it is. If so, what's the slow set type called? Kerra-slow?????

Z

A flexible adhesive is suitable for everything a non-flexible is suitable for, but not the other way around.

For setting times and such for the mapie products, check out their website - www.mapei.co.uk - and look in "products for ceramic and stone materials".

[zygo]

So eventually I suppose the non-flexible type will be phased out as redundant.

Thanks for the link to Mapei. Wanting to avoid Screwfix, I called Mapei yesterday for stockists in Essex (as surprisingly their website does not have that facility) and they gave me two firms. Neither has a website but from what I can see they are tilers, rather than tiler suppliers. Screwfix have a branch near me so maybe I'll go there after all.

z

[zygo]

....being from Bal I couldn't possibly comment on Mapei products.....

OK, so who stocks BAL products in Essex? and what are your product names for slow setting bagged flexible adhesive and black flexible grout? Preferably within reach of Chelmsford or Basildon, Essex.

(I left you another vote of thanks, GazTech, for the laugh you gave me!)

Cheers,
Z

[grumpygrouter]

BAL Single Part Flexible is the adhesive and if it was me I would still use the Mapei grout (Ultracolor Plus). As for stockist, 'fraid I can't help there, though Topps usually stock the stuff but they are expensive!!

[zygo]

This is gonna sound naive but I was planning to apply the adhesive to the floor and then lay the tiles. Should I be applying the adhesive to the tiles? (12in granite onto skimmed concrete subfloor).

[grumpygrouter]

No, apply adhesive to the floor and trowel with appropriately sized trowel. Only lay enough adhesive to fix your tiles within the open time of the adhesive - usually about 15 to 20mins - and then trowel out the next bit. take you time and ensure that you reduce/eliminate any lipping between tiles as you lay. Try to keep the tile surface clean of residual adhesive as you go along, and clean out your grout joints as well.

[deanotile]

If you follow the power point I sent you starting from the back of the room each section is a bay. As grumpy described trowel the adhesive in the first bay do not cover the lines with the adhesive leave them showing so you do not go out of square. Fix the tiles in the first bay then repeat the process working back to the door.

[zygo]

Thanks deanotile.
I just had this moment of hesitation that I had ASSUMED it rather than read it. I have tiled bathroom and shower room walls (only) in the past and never thought for a moment that I should apply addy to he tile but I read something ambiguous on a website today that made me wonder if I was going mad. Think of it as a momentary lapse of common-sense.
Next I shall be asking for advice on grouting as I now understand that 6mm spacers are quite normal for floors and the flexible grout from Mapei and BAL seem to work up to a staggering 20mm. I was planning on 3mm spacers as it's not a specially large room.
z

[deanotile]

3mm spacers it's all good

[zygo]

Thanks.

3mm spacers it is then.

z

[Dave]

Also zygo the floor you are wanting to tile is classed as a floating floor....but with it bieng a screed and not timber it can be tiled....But i would advise flexible adhesive and grout......a lot of new builds/extensions now have this type of insulation built within the floor structure and flexible products must be used...it's all down to thermal changes etc in the substrate....

[zygo]

That makes sense, Dave. I like replies and advice that appeal to my common sense. I might not have mentioned that I laid the dpc and the Celcon but I had a plasterer lay the sand/cement on top as I thought it would be nicer to have it level!

I would not have known this was a floating floor (which I thought had something to do with loose laying those awful laminate floor planks on top of foam underlay). But you live and learn.

Thanks.
Z

[Dave]

It's the foam layer that classes it as a floating floor...as the screed is really just floating on top of it,,if you see what i mean....

p.s I think the terminolgy is a warma floor.....

[zygo]

Oh.
Did I mention that the screed on top is 80/100mm thick?
Z

[Dave]

Exactly what it should be......