UFH and decoupling membrane which way round

[wetdec]

imo over that way you know you have an absolute bond between floor and membrane. As has been said either is ok................

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[The Legend; Phil Hobson RIP]

The Durabase I have is an uncoupling membrane a bit like a sandwich of thin plastic with raised discs on one side, bought it of someone on the forum, may even have been you Wetdecs. All I need to know really is do I fit the ufh first then slc then durabase then tiles or is it durabase ufh slc then tiles, I have two conflicting sets of advice and to be honest it makes sense to me either way. Thanks to all contributors so far.



Either way Stevoe mate, Gerard from Dural will confirm this.If you need his mob no. PM me or post again here. Ci is de-coupling WP primarily tanking

 

[peckers]

ufh
slc
ci
tiles

 

[wetdec]

Durabase Ci Suppliment.


CI Matting – Underfloor Heating Systems



The increased stress within the installation caused by thermal movement can cause problems to the installer. Separation or Isolation Membranes are ideal for removing shear stress from tiled installations. This removes a major obstacle to fixer confidence in installing these systems.

By absorbing this stress the membrane allows the tiled surface to remain intact. The air spaces under the membrane have two benefits, they allow residual moisture to gradually escape therefore helping to prevent cracks forming in the substrate. The air spaces also allow the heat to be spread evenly across the floor surface making the heating action more general and effective.

CI matting requires no special precautions when used within a heated installation.

The only requirement is the selection of an adhesive suitable for use with the substrate. This adhesive must be capable of bonding to the substrate and achieving a mechanical fix with the fleece on the underside of CI matting.

The electrical heating elements should be installed onto the surface of the CI matting following the manufacturer’ instructions. Standard thin set adhesive can be used to fix tiles in place. A modified flexible grout should be used to complete the installation.


..

 

[peckers]

Durabase Ci Suppliment.


CI Matting – Underfloor Heating Systems



The increased stress within the installation caused by thermal movement can cause problems to the installer. Separation or Isolation Membranes are ideal for removing shear stress from tiled installations. This removes a major obstacle to fixer confidence in installing these systems.

By absorbing this stress the membrane allows the tiled surface to remain intact. The air spaces under the membrane have two benefits, they allow residual moisture to gradually escape therefore helping to prevent cracks forming in the substrate. The air spaces also allow the heat to be spread evenly across the floor surface making the heating action more general and effective.

CI matting requires no special precautions when used within a heated installation.

The only requirement is the selection of an adhesive suitable for use with the substrate. This adhesive must be capable of bonding to the substrate and achieving a mechanical fix with the fleece on the underside of CI matting.

The electrical heating elements should be installed onto the surface of the CI matting following the manufacturer’ instructions. Standard thin set adhesive can be used to fix tiles in place. A modified flexible grout should be used to complete the installation.


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so do you stick the heating mat direct to the top of the ci and then flood with slc so as it fills the cavitys in the ci and then goes over the top of the matt? if you wern't using slc and decided to just tile direct onto the heating mat then wouldn't it be very difficult to force the adhesive threw the heating mat and being able to fill the cavitys in the ci? ensuring the cavitys are full? or would you suggest filling the cavitys in the ci first with tile adhesive allow to dry then heating matt then slc or just tile? I have done it the other way matt slc decoupler then tile and never had any issues. I have always thought that by doing it this way that any expansion caused by the heating matt will not affect the tiles due to the decoupler being between them. But it seems i could be wroung..

 

[wetdec]

so do you stick the heating mat direct to the top of the ci and then flood with slc so as it fills the cavitys in the ci and then goes over the top of the matt? if you wern't using slc and decided to just tile direct onto the heating mat then wouldn't it be very difficult to force the adhesive threw the heating mat and being able to fill the cavitys in the ci? ensuring the cavitys are full? or would you suggest filling the cavitys in the ci first with tile adhesive allow to dry then heating matt then slc or just tile? I have done it the other way matt slc decoupler then tile and never had any issues. I have always thought that by doing it this way that any expansion caused by the heating matt will not affect the tiles due to the decoupler being between them. But it seems i could be wroung..

We use a pourable adhesive over the cable (just cable not meshed) and bring it flush ready to tile. To fill the voids and leave to dry I supose is a possibility but would draw out your working time.

The heat from an underfloor cable doesnt have the capacity to crack the tiles. An uncoupling membrane used over a heated floor isolates the tiles from the screed movement during expansion and contraction which involves huge tensions and will crack your tiles.

The ci pdf doesnt cover this aspect so what I posted was written as a suppliment to the pdf.

The most importand bond when using an uncoupling membrane is the one to the actual floor the less fiddling in that area the better.

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[wetdec]

Your welcome.........

,

 

[DHTiling]

IMO an Uncoupling membrane works more efficiently over the top and just the tiles on it..

They can be used either way but on top makes the uncoupling work better, as in uncoupled from ALL stress.

Ditra do point this issue out, so i wonder why Dural don't..??

 

[wetdec]

Cant answer that one Dave you better ask them probably involves maths. Would say tho if your cable is under the membrane and the screed tears so does your cable as there is no give there............

By uncoupling you are isolating a problem should it occur the problem originating in this instance at the screed they are designed primarily to counter screed difficulties

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[Dumbo]

just thinking if it was a wetroom wouldnt it be better to lay wp over the whole floor and tray and not underneath?

ted

 

[wetdec]

Ye dead right Neil

,

 

[Dan]

Just bumping some of the older popular (sometimes not so popular) threads. Probably wont be current discussion these days but I just need to do it. So just ignore the thread if it's not current for you.