SBR cement slurry as tiling adhesive?

[Harold Davis]

Hi,

I'm making a hearth. I've built a shallow wall around the edge made of stone blocks, and in the middle I want to lay 17mm thick brick slips on top of the screed that I made using sharp sand/cement/SBR (ratios 2.5/1/0.1). The brick slips need to be level with the wall.

The problem is that the screed is a bit too high, and so I need to save as much space as possible in whatever I use as adhesive under the brick slips.

Would it be feasible to use SBR cement slurry (say 1.5/1 cement/SBR) as the only layer between the screed and the brick slips? (This is not counting a wash of SBR with water on the screed if required, which will have practically no thickness, but I was guessing this wouldn't be needed because both the slurry and the screed contain SBR already, so I'm not anticipating poor adhesion. Of course I could be wrong.)

Many thanks in advance for any help with this.

Harry

[tabbypurr]

I don't see a problem

NT

[Tim Watts]

Is this the wall of the hearth or the floor? Is this going to support a fire or stove and thus needs to survive high temperatures?

Having used SBR a fair bit, I don't think this is a case where it would work well.

If it's not going to have to survive high heat, just use a proper tile adhesive - most of those will go down to 1-2mm bed thickness if you try. I'd probably use Bal Bluestar for something like this, or maybe Greenstar.

The SBR plan is going to have 2 problems:

1) It's very slippery so the tile is going to need to be pressed into place for the full set time.

2) If you did need to remove the tile and it did bond (see 3), it's not coming off, ever.

3) It's not really a good gap filling mix, so whilst you think you want practically zero thickness, you do need some to work into the texture of the surfaces.

I you need something that supports heat, how about fire cement? Would that work?

[Harold Davis]

Tim Watts wrote in news: [e-mail]:

It's the floor, in front of an open fire, so some heat but no high heat and not a lot of weight either.

Under the grate itself, which won't be seen, I'll put some heat-resistant screed (Vitcas brand) and no brick slips.

Any views on Nicobond Quickfix, which is what I used to stick the same brick slips to the chimney breast? My feeling is that I probably couldn't get it down to 1-2mm.

The tiles are quite heavy, and I have ample so maybe I could put other ones on top to press them down. Not sure how much weight would be needed.

Oh that's not a problem! :-)

OK got you. Maybe I could paint both surfaces with SBR and water?

That's made for higher temperatures, but I've got some. Not sure what the advantage would be over just ordinary sand plus cement in this application though.

Harry

[Harold Davis]

[e-mail] wrote in news: [e-mail]:

Thanks, NT. What do you think of Tim Watts's ideas on this?

I just want to be sure I don't eff this up, having already got the screed higher than I wanted to!

Harry

[Tim Watts]

In that case, I think a mix-it-yourself (powdered) cementious floor tile adhesive is your best bet. There is no reason that cannot be squeezed down to 1-2mm - it's very fine powder, no coarse sand. It will handle the heat as mine are done with the same, even under the stove, which gets bloody hot.

[John Rumm]

FWIW, a builder friend of mine always claimed good success using nothing but a mixture of plain ordinary portland cement and water as a floor tile adhesive... I don't recall him adding SBR or PVA to the mix, although it was usually applied to a screed that may have included some anyway.

[Capitol]

When I was a lad working as a builders labourer, we always used neat cement and water. The mix was also the grout and the tiles were quarry.

[Tim Watts]

How did that work? All the times I've mixed cement slurry (as a bonding aid), the lumps left after I've scraped out the mixing pot always seemed very soft, even after some considerable time. I *thought* you needed some sort of filler, even if that was very fine sand.

I'm not doubting you, but it's not been my experience of neat cement...

[Capitol]

The consistency when mixed is very close to putty. It was applied with a pointing trowel.

[Tim Watts]

Ah - perhaps it was to do with the slurry I've mixed being very wet (so as to paint on old concrete to get a bond).

[tabbypurr]

Fire cement is absolute s**te. It's used when nothing else can take the heat.

NT

[tabbypurr]

You can stick floor tiles down either way. Commercial tile adhesive cement or acrylic mixes, or a cement & sand mix. I would not use fire cement though. If using cement, soak the tiles overnight first.

NT

[stuart noble]

I stuck some loose quarry tiles down on our front path with Gripfil Original. No room for any thickness of adhesive, but seems to have worked well