SLATE on uhf and trav on fibre screed help!

[Concrete guy]

I also worked with it for many years, in fact I remember when it was first introduced and widely misused, hence the numerous conversation I had with Schluter about it at the time and over the subsequent years. This was back when it was a corrugated design not the square cells it is these days.

Don't shoot the messenger! I'm just passing on the information provided by the manufacturer.

 

[Protilers]

I remember the days that schulter said stick Ditra down with anything.......even bucket adhesive........my, my times have changed...and if I gave you an opinion on what they say "today"....you can bet your life it will change "tommorrow!"......

best wishes

Lee

 

[Rizzle from the Portizzle]

well you may be pleased to now that me gary lee will be testing the decoulpers ditra deco mat dural vs bal flex the plan is to cut ply into 400x400 then cut in half then cover with decoulplers then tile .also use bal flex and tile wait a week to go off then screw to black and decker work bench vice then use vice to see how much movement apart in can take in mm

 

[gamma38]

well you may be pleased to now that me gary lee will be testing the decoulpers ditra deco mat dural vs bal flex the plan is to cut ply into 400x400 then cut in half then cover with decoulplers then tile .also use bal flex and tile wait a week to go off then screw to black and decker work bench vice then use vice to see how much movement apart in can take in mm

Here we go again, I love the tests you guy's do. No messing just honest true to life results. Good work :hurray:

 

[Rizzle from the Portizzle]

well went to trimline today they gave me these and are very keen for us to give them feed back to

 

[bugs183]

I'm working on a big Anhydrite floor for a few weeks so i'm going to do a test of SBR primer versus epoxy, and how well they stick down gypsum based adhesive, inc ditra mat. I'll take some piccis.

 

[Rizzle from the Portizzle]

I'm working on a big Anhydrite floor for a few weeks so i'm going to do a test of SBR primer versus epoxy, and how well they stick down gypsum based adhesive, inc ditra mat. I'll take some piccis.

thats what we all should be doing and sharing its about time we we told the reps that does not work and backed it up .we have been test dummys for long anought

 

[timlee77]

spoke to schluter they said they would always recommend ditra as it has 3mm of movement allowance!! if the goalposts move any further we'll be of the pitch :mad2:

 

[Concrete guy]

I still say I still see absolutely no advantage of an uncoupling membrane for the OP's specification.

The screed is a stable fibre reinforced sand cement base which has had 9 weeks curing time, as long as the UFH has been has been commissioned for a 28 day period there should be complete stability.

Any flexible additives in the adhesive and grout will absorb any sheer force comfortably.

Put it this way, if this floor were to expand and contract by enough that an uncoupling membrane were required, serious consideration should have been given to expansion joints, which I assume are not even in the equation.

I see Ditra matting the area as an unnecessary expense in labour and materials that will also reduce the efficacy of the heating system.

 

[TT Tiling]

i do both and have never had a prob , as long as its dry use a good add and flex grout no probs

 

[Ajax123]

Screed for slate is about 2 inch fiber screed ufh. its been down 7 weeks and will be 10 weeks when i tile. trav room not ufh. i forgot to mention the house is extension so im carrying existing slate opus from kitchen area (already tiled slate) on through extension kitchen not heated and seperate substraight so im putting movement joint in. what about hight of existing kitchen floor to hight of extension with ditra? there is another membrane called norcross permalayer Permalayer (1.2m width) its only 1.8mm thick ?

2inch is way too thin for a sand cment screed. That in itself means ditra is needed. Also the British stone federation Recomend natural stone on heated screed should be uncoupled. This is also a requirement of the tling standard although it does not state how uncoupling should be acheived. Ditra or similar would be an obvious choice.

 

[Ajax123]

I'm working on a big Anhydrite floor for a few weeks so i'm going to do a test of SBR primer versus epoxy, and how well they stick down gypsum based adhesive, inc ditra mat. I'll take some piccis.

What on earth would you want epoxy for with a gypsum addy?? A simple penetrative acrylic would be fine

 

[Ajax123]

I still say I still see absolutely no advantage of an uncoupling membrane for the OP's specification.

The screed is a stable fibre reinforced sand cement base which has had 9 weeks curing time, as long as the UFH has been has been commissioned for a 28 day period there should be complete stability.

Any flexible additives in the adhesive and grout will absorb any sheer force comfortably.

Put it this way, if this floor were to expand and contract by enough that an uncoupling membrane were required, serious consideration should have been given to expansion joints, which I assume are not even in the equation.

I see Ditra matting the area as an unnecessary expense in labour and materials that will also reduce the efficacy of the heating system.

It is not always about expansion and contraction. Ditra will help stabilise the tile face in the much more likely event of long term shrinkage cracking. Additionally it is not always to do with the screed expanding and contracting but the tile face itself which In The case of trav could easily cause it to crack along the natural fissures which would be exacerbated if the tile were restrained.

 

[Concrete guy]

2inch is way too thin for a sand cment screed. That in itself means ditra is needed. Also the British stone federation Recomend natural stone on heated screed should be uncoupled. This is also a requirement of the tling standard although it does not state how uncoupling should be acheived. Ditra or similar would be an obvious choice.

50mm is just fine for a screed that's fibre reinforced.

I'm interested in the BSF and Tiling Standards you mention. Do you have a link to these I'd like to read up on them?

It's quite a few years since I was last installing and at that time neither were the case (as you can see from the technical advice Schluter gave me back then) so it would be interesting to read up on modern requirements.

Are these suggestions? Advice or British Standards?

 

[Gazzer]

Ooooh I feel a :lurk5: moment coming on !