Expansion Joints- Opus Pattern Floor.

[MW Smith Ceramics]

Just a quick one ,

So I've got a 75 metre floor coming up, existing kitchen, hall and utility with solid quarry tiles that we are taking up back to concrete base then 80 to 100mm sand & cement screed to the extension about 30 square metres ( no underfloor heating in the screed ) so the builders are bringing new floor up flush with existing.......now the client wants the floor laid ASAP after the screed has gone in ( this is a must ) so this is the method of fixing I'm looking at doing as follows......

Tiling onto the existing concrete with an S1 adhesive then on the new screed laying Schluter ditra mating with an S2 adhesive up to/not over the joint between old & new floors and putting a Mapei mapesil mastic seal movement joint in about 5mm as I'm using Mapei ultracolour grout the mastic is a bang on match....a little wider than 3mm joints in tiles and laying onto the Schluter with an S1.....

My only concern is the tiles are natural slate opus Romano pattern so the movement joint may be an eyesore!!.....any thoughts / advice on this one would be really helpful

Thanks

 

[MW Smith Ceramics]

Oh I'm laying Schluter 14 days after screed has gone in......

 

[Old Mod]

Oh I'm laying Schluter 14 days after screed has gone in......

Make sure u tape and seal Ditra joints with Kerdi Band & Kerdi Coll adhesive, if you're using it to fast track floor.
Schluter will not guarantee install if u use tile adhesive.

 

[MW Smith Ceramics]

Hi 3fall,

Right okay mate, Schluter didn't mention that!......what are your thoughts on the movement joint......I already know the builder will say no......is there another way around it???......

 

[Old Mod]

Hi 3fall,

Right okay mate, Schluter didn't mention that!......what are your thoughts on the movement joint......I already know the builder will say no......is there another way around it???......

Ok so moved this to its own thread Mark.
With a pattern like that, the best u'll manage without cutting pieces in half to accommodate expansion, is work out which part of the pattern has most joints that line up along it, put that line on your expansion joint.
Discuss with client from there about possible outcomes if u don't cut the tiles that bridge the expansion.

 

[Old Mod]

Don't forget u'll need a green screed adhesive to lay your decoupler.
Regular on top.

 

[MW Smith Ceramics]

O

Don't forget u'll need a green screed adhesive to lay your decoupler.
Regular on top.

okay bud, yes I see what your saying there but of course where we run a tile over the movement joint this could hairline crack - ( possibly ) all depending on movement but surely it helps with no UFH........on some contracts we have done in the past on any big domestic jobs that required movement joints with a modular pattern floor we would put a material called pesilastic - ( an anti fracture membrane ) over the movement joint and any cracks in the screed......where as on the commercial we would Schluter up to the movement joint and then install construction joints.........what do you think to running the Schluter say a metre over the joint between the 2 floors ???

 

[Old Mod]

All I can say is that it's not designed for that, clients would need to be aware of risks involved.
Trouble is if they had future problems and pointed the finger at u, u wouldn't legally have a leg to stand on.
I can't say yes that will work, cos it's not the correct way to fit a decoupler.
It may work, it may not.

 

[MW Smith Ceramics]

Your right mate, it needs a movement joint.....period.......Schluter is to accommodate contraction/shrinkage & not to be fitted over movement joints at all then?.....bloody hell we used to do that all the time with pesilastic!.....this is what makes this forum great.......getting the right answers from industry professionals ........I'm going to have a chat with Schluter on Monday see what they are saying.....so thanks for your time anyway 3fall......much appreciated......

 

[Old Mod]

The new screed will dry slower than normal with a covering of Ditra, however this is an advantage, there'll be less chance of cracking or curling.