Substrate Query

[CUSH68]

Hi all

Quoting for a kitchen floor. Problem is a wall has been knocked down and the tiles will now cover ply (new area) to concrete(old area).
Tried to talk customer into ditra matting but he didn't really want to know.
Expansion joint would also be a problem as its a 3 size pattern.
Any help would be appreciated,

Cheers

Mark

[wetdec]

Walk away or mesh it your problem is going to be deflection or settlement at the transition before latteral m8


Tiler

[CUSH68]

Thanks for the quick reply wetdec,

Could you explain the method you would use to mesh between the substrates, something I have never done before.

Cheers

Mark

[robbo]

I think the customer needs to be told out right that they need to use some sort of proprietary product to combat the deflection between the two substrates or tiles will crack along the joint where the two floors meet as a timber floor will always slightly flex and concrete normally won't!

[wetdec]

Mesh sheet/band they use for plastering over you may of seen it when they form arches.

Fix it to both substrates across the transition.......prime......flex adhesive.......mesh...... screwed down tight while wet ........this will strengthen the joint and lessen the chance of deflection for you.

Obviously there should be as little vibration as possible before you start ye.


tiler

..

[robbo]

Perhaps Fast flex on and around the join area would be a good idea, but its not cheap....

BAL Fastflex Powder & Liquid
A two part, rapid-setting, sulphate-resistant, water-resistant and frost-resistant floor tile adhesive and isolating, anti-fracture underlay, suitable for use in interior and exterior locations. Suitable for fixing ceramic floor and porcelain tiles and mosaics (including fully vitrified), dark natural stone and slate. Suitable for use on tile backer boards, glazed tiles, concrete bases, cement:sand screeds, tongue & groove floorboarding, plywood overlay, floating plywood/chipboard floors, ceramic/quarry tile/terrazzo/hard natural stone bases, vinyl tiles/sheet, mastic asphalt, steel, glass reinforced polyester (GRP), steel and galvanised steel. Conforms to BS EN 12004, Type C, Class 1F.

[Dave]

Deflection needs be at a very minimum for mesh to work....IMO.....works good for lateral though...........

[pjtiler]

without an expantion joint it,ll
quack

[mart1]

Lay a 5 micron thick visqueen sheet ( Slip membrane )over the joint your concerned about and there will be no deflection transfered to the finished surface. no need for any matting of which is only money for old rope and the clever germans have ceased upon.

[grumpygrouter]

Lay a 5 micron thick visqueen sheet ( Slip membrane )over the joint your concerned about and there will be no deflection transfered to the finished surface. no need for any matting of which is only money for old rope and the clever germans have ceased upon.

How does it do that then?

[mart1]

This method of using a slip membrane has been used throughout the construction industry for many a year and is still probably classed as a trade secret. just think about it.. you are debonding the finished surface from the main substrate thus it does not matter what problems may occure with any settlement. Believe me this works and i can say that with all honesty.

[whitebeam]

I'd need to see it, Then I would probably understand it a bit more.

[pjtiler]

oh this old chestnut re appearing eh
fine for lateral movement but horizontal quack quack

[Pawelzik]

...wall has been knocked down and the tiles will now cover ply (new area) to concrete(old area). Tried to talk customer into ditra matting but he didn't really want to know....

As Dave said I suppose too that mesh works only is too weak.
Insist on the uncoupling method , you are right and the pro, otherwise you can´t guarantee or stay away from the job.

Or lets see it from the customers side: I think he/she can understand the deflection problem so he/she should understand that some additional work must be done. Are we talking about a huge amount of money? No, not realy compared to what it will cost if the tiles are laid, will crack and a big area must be lifted up again for repair works.

May be you can ask Wetdecs if there is a thin uncoupling matting for less.
Martin

[grumpygrouter]

This method of using a slip membrane has been used throughout the construction industry for many a year and is still probably classed as a trade secret. just think about it.. you are debonding the finished surface from the main substrate thus it does not matter what problems may occure with any settlement. Believe me this works and i can say that with all honesty.

Not really sure what you are saying here Mart. This indicates to me that you have not got the top surface attached to the substrate but just to a piece of film, is that right? If so, isn't this exactly what Ditra or Durabse does as an "isolating" layer? These substances do not provide security against deflection, only lateral movement. I don't see how a 5 micron thick sheet of polyethylene can stop several dozen kilograms from deflecting a floor joist for instance.

Have you go examples you can show us or some sort of document?

Cheers.

[CUSH68]

Got some sense out of customer today. He has changed his mind about the three size pattern and now wants 600 x 300 porcelain brickbond. Is this a case now where if the setting out alows I can run a grout line along where the 2 substrates meet and fit an expansion joint ( or matching silicone joint)?
Thanks all for the ongoing help

Mark