Hot Water Under Floor Heating On A Sand Cement Screed

[lm tiles]

Any advice on tiling onto a sand cement screed laid over underfloor heating pipes . I would imagine the screed will be pretty weak not like a concrete floor . Ceramic tiles ..

 

[DHTiling]

If the screed is laid right then it won't be weak....use flexi products to tile with...Also a product like ditra mat is ideal for this type of installation.........

 

[lm tiles]

Thanks for getting back as quick . would you advise sbr bonding first

 

[DHTiling]

Most definitely...........:hurray:

 

[lm tiles]

will do m8 .its great to have a back up like this site . does wonders for your confidence .

 

[enduro]

A plumber mate of mine when they have laid this type of heating turn the heating on for a couple of days as hot as it will go then let the floor go cold before i tile, dont know if this helps to stop to much expansion.

 

[Perry]

this may help Pete

http://www.pci-uk.com/PCIUK/En/tilingadvice/howtoguides/tilingontounderfloorheating.htm

 

[GazTech]

this may help Pete

http://www.pci-uk.com/PCIUK/En/tilingadvice/howtoguides/tilingontounderfloorheating.htm

nice one pj...the bit about heating gradually was spot on !:hurray:

 

[Perry]

Had one turn the heating on to 30 deg while still tilling on limestone nice one
:furious3: :mad2:

 

[GazTech]

Had one turn the heating on to 30 deg while still tilling on limestone nice one
:furious3: :mad2:

Dear me ..how considerate...did you revert to mixing rapid by the cup full....lol

 

[Perry]

one of those clever guys who know everything :furious3:

 

[Leatherface]

Guys - to do the job properly - first the screed should be allowed to dry out naturally - dependant upon conditions. Once dry the underfloor heating should be switched on and gradually brought up to maximum operating temperature - . Leave on once max temp has been reached for a couple of days , then allow to cool down prior to tiling. The reason for switching the heating on first is to allow for any initial expansion and cracking of the screed due to the heat.
Once tiles have been fixed again leave heating off for a couple of weeks, then again heating should be switched on and gradually brought up to maximum temp again.
Sounds a drawn out process, but a safe one. This is what I always advise and have never had any tiles crack or lift.

 

[DHTiling]

Spot on advise......works every time.........

 

[White Room]

If I was laying screed on under floor heating, It be would ready mixed with fibres mixed in for strength and leave to cure, never seen covering over screed, but 60mm have even layed 75mm,and your'll need more than a couple weeks. No heating until screed has cured notch up slowly, otherwise cracking will happen. They say concrete reaches its maximum strength after 30 years

 

[Leatherface]

Cheers Dave - will try to be as helpful as I can, where I can. Fair play ti IM Tiles for asking - have seen a few jobs done where tilers have not asked and carried on regardless with disasterous and costly results

 

[DHTiling]

And it will still happen....but hopefully we can show some the errors of there ways so to speak......keep it up mate...

 

[Leatherface]

As far as I know the advice is allow one day per mm of screed for drying out again dependant upon conditions. Please correct me if I am wrong

 

[DHTiling]

its about that..but the average screed is 30 days or so..but there are products that can be used to tile onto screeds as soon as they can be walked on..Like ditra mat.. it is a vapour equalising membrane and great for fastrack installations...and bal do a green-screed adhesive..........

 

[White Room]

As far as I know the advice is allow one day per mm of screed for drying out again dependant upon conditions. Please correct me if I am wrong

Same as, but no nobody wants to wait that long, with solid plastering you would have to wait 6 weeks, could'nt do that now

 

[Leatherface]

Yes I was using Ditra Matting on a job in Cheltenham last week - didn't know it was suitable for underfloor heating though ?
Bal Green Screed adhesive is extortionate in price.
Also if you are able to have an input into the screeding process, which is usually unlikely, some manufacturers do a Fasttrack screed that can be tiled onto in a week or so - Mapei are one such supplier

 

[DHTiling]

Yep.. ditra is great for UFH.....because it isolates the two surfaces thus less chance of debonding due to expansion.....

 

[Leatherface]

Not over keen on the stuff though - hate filling all the holes up

 

[White Room]

Adhesive, ditra, adhesive and then tiles. It'll cost a fortune in heating a floor, cheaper to get a pair of slippers:lol:

 

[Fekin]

Interesting thread

All these soft buggers with ufh.. whats wrong with goold old slippers :lol:

 

[lm tiles]

Thanks for all the help guys ..I have only tiled on top of electric at heating so thought i had better ask as i keep saying this site is worth its weight in gold anyone who does'nt ask ,does'nt learn . I think this lady thinks i'm trying to put the job off till after Christmas i'll show her a print off of these answers and that should at least back me up .

 

[GazTech]

Thanks for all the help guys ..I have only tiled on top of electric at heating so thought i had better ask as i keep saying this site is worth its weight in gold anyone who does'nt ask ,does'nt learn . I think this lady thinks i'm trying to put the job off till after Christmas i'll show her a print off of these answers and that should at least back me up .

good thinking mate

 

[Dan]

Just bumping some threads in the underfloor heating forum. You can now find and search for both electric underfloor heating and water underfloor heating threads. By the way, if you feel some of the threads you want to be seen at the top of the forum need to be bumped back, for the next month or so from now, feel free to do that. Although it's not usually something we allow, whilst we're going through this process of changing over forum software, we see the need for this to happen.

 

[macten]

its about that..but the average screed is 30 days or so..but there are products that can be used to tile onto screeds as soon as they can be walked on..Like ditra mat.. it is a vapour equalising membrane and great for fastrack installations...and bal do a green-screed adhesive..........

Would mapetex also be fine? Also if you are using a product to fastrack tile installation over wet UFH how does that work when the ufh needs commissioning prior to tiling? Does the screed not have to still dry out naturally prior to commissioning or does a membrane mean you can commission earlier?

 

[One Day]

Would mapetex also be fine? Also if you are using a product to fastrack tile installation over wet UFH how does that work when the ufh needs commissioning prior to tiling? Does the screed not have to still dry out naturally prior to commissioning or does a membrane mean you can commission earlier?

very old thread but seeing as you asked.... I believe only ditra is suitable for use over uncommissioned ufh. others require commissioned floors. Ditra is hands down the best uncoupling membrane there is. Everything else is a lesser copy at best or repackaged roofing membrane at worst.

 

[Old Mod]

Would mapetex also be fine? Also if you are using a product to fastrack tile installation over wet UFH how does that work when the ufh needs commissioning prior to tiling? Does the screed not have to still dry out naturally prior to commissioning or does a membrane mean you can commission earlier?

I believe you can turn UFH on after 3 weeks Nick,
And if I'm wrong, hopefully someone will correct me.