UFH mats and Hardie backer board

[RDTiling]

Hi all

A customer has a 4m2 bathroom floor, which has floorboards down at the moment. They are fairly solid, so just a few extra screws into the joists to make 100%.

They have asked me to quote both with and without UFH, (first time I've been asked to lay UFH).

Im looking to overboard with 6mm Hardie backer board, but my question is do I also need to add a thermal board like Marmox or can I lay the UFH mat directly onto the hardie, cover with SLC and then tile?

Thanks,
Rich

 

[Qwerty]

I personally would forget the hardi and lay insulation boards instead. Fix with bagged cement tile adhesive then lay out the UFH on top of that. SLC over the lot to encapsulate it all then when dried tile away. Don't forget to check the UFH resistance before, during and after. I always use a UFH alarm for peace of mind

 

[Sean SML Tiling]

Hardie will be fine

 

[Qwerty]

Hardie will be fine

Yes, Hardi will indeed be fine. Out of interest what would be your reasons for choosing Hardi over Marmox? Always interesting to hear differing opinions on this. I'm a Marmox man through and through and used to fix Hardi all the time.

 

[RDTiling]

Thanks for the advice guys.

Two different answers to get to the same end result! - I'll price it both ways and see which one come out cheaper for them.

Good shout about the resistance checks - looks like contents of my tool chest is about to increase again! Any recommendation on which resistance checkers to purchase? Or are they all as good as each other?

 

[RDTiling]

As I only started tiling in June/July I've so far only over boarded with ply but I'm looking to only start using cement boards from now on.

i was always under the impression that insulation boards were only there to prevent downward heat loss on a solid substrate like concrete, which was why I initially thought Hardie plus insulation board as it was floor boards. Good to know though that I don't need both though and this another thread I'll print down for my 'noobie' manual!

 

[Qwerty]

I changed to Marmox as it is cheaper, available in varying thicknesses, cheaper, easier to cut, has superior thermal properties and a lot lighter!

As for brands of multi meters...... they pretty much all do the same job. Find a decent cheapish one from Toolstation or similar and you will be fine.

Don't forget to fit sensor cable when laying the UFH, and mark on a scale diagram where the wires are

 

[RDTiling]

Top-advice as always Geoff - many thanks and it's very much appreciated.

 

[Stef]

I changed to Marmox as it is cheaper, available in varying thicknesses, cheaper, easier to cut, has superior thermal properties and a lot lighter!

As for brands of multi meters...... they pretty much all do the same job. Find a decent cheapish one from Toolstation or similar and you will be fine.

Don't forget to fit sensor cable when laying the UFH, and mark on a scale diagram where the wires are 

Geoff, where are you getting your marmox boards from?

everywhere ive looked its always more expensive than Hardie.
i used wedi in my own downstairs bathroom (6mm) & my only dislike about it was when kneeling to tile the floor my knee would leave a dent where i had been.

 

[Qwerty]

Geoff, where are you getting your marmox boards from?

everywhere ive looked its always more expensive than Hardie.
i used wedi in my own downstairs bathroom (6mm) & my only dislike about it was when kneeling to tile the floor my knee would leave a dent where i had been.

Tilefix direct Stef

http://www.tilefixdirect.com/category/marmox-tile-backer-insulation-boards

I always use an off cut of Marmox on top to prevent denting

 

[Qwerty]

Here is the type of monitor alarm that is handy.....

http://www.ebay.co.uk/itm/like/3507...ff3=1&ff11=ICEP3.0.0&ff12=67&ff13=80&ff14=102

 

[RDTiling]

I always use an off cut of Marmox on top to prevent denting 

The simplest of tiling tools! It's only when someone says something like this you think 'oh yeah....why didn't I think of that'

I'l get both an alarm and multimeter ordered....both handy things to have.

 

[Sean SML Tiling]

Yes, Hardi will indeed be fine. Out of interest what would be your reasons for choosing Hardi over Marmox? Always interesting to hear differing opinions on this. I'm a Marmox man through and through and used to fix Hardi all the time.

Just nobody stocks marmox by me but I used marmox a few times and I do think its a better product.

 

[Ajax123]

As bathrooms are considered "special areas" under part p of the building regs and you are not a "competent person" under the regulatory guidance you should not technically be installing fixed wiring systems without the involvement of either building control or a "competent person" who can certify the work under the regulations. If this doesn't happen it is technically an unlawful installation. In itself this is not an issue unless there is a problem with the floor e.g. A fire at which point you could find yourself in some strife.

This is always a concern of mine when hearing about underfloor heating systems in kitchens and bathrooms.

How do most tilers deal with the issues created by part p

 

[Qwerty]

Final connection made by certified electrician

 

[RDTiling]

I was planning on laying the boards and UFH mats, but have an electrician connect it to the mains, in order that any warranties are validated. I'm assuming a qualified electrician comes under 'competent person' or 'registered third party' as mentioned in part p?

 

[Ajax123]

To meet part p in kitchens and bathrooms the electrician has to be a member of a competent persons scheme e.g. Niceic registered. Provided he is registered he can self certify the work. Problem as I see it is that as he has not installed the cables he will only certify the connection so the cable installation itself is not certified...

 

[CJ]

Some warm up kits come with the alarm.......you only need the one in ya toolbox.

 

[Qwerty]

To meet part p in kitchens and bathrooms the electrician has to be a member of a competent persons scheme e.g. Niceic registered. Provided he is registered he can self certify the work. Problem as I see it is that as he has not installed the cables he will only certify the connection so the cable installation itself is not certified...

My sparky always sees my stages of work in photos or in person, sees the resistance readings I record and certifies every installation no problems. He knows less about installation (laying) of electric UFH then I do!!!

 

[Qwerty]

Some warm up kits come with the alarm.......you only need the one in ya toolbox.

Yes, Warmup kits from Topps often come with a "watchdog" but I think they have stopped this now as have started selling the trade kits instead. My watchdog has just died

 

[Chalker]

Ugh. Dusty no more ply, hardy backer.
converted to insulation boards a while back, easier to cut and lay. Can be got for same price as cement board.
recent job customer supplied Marmox boards, they were good but I have used PCS insulation boards from tile town and they were much harder and heavier . So a vote from me for PCS.
i use them on solid or timber floors and instead of plasterboard in shower areas.

 

[White Room]

Here is the type of monitor alarm that is handy.....

FloorheatPro Electric Underfloor Heating Cable Circuit Monitor | eBay

Bugger...said I would'nt buy any more tools just yet....

 

[jonnyc]

Yes, Hardi will indeed be fine. Out of interest what would be your reasons for choosing Hardi over Marmox? Always interesting to hear differing opinions on this. I'm a Marmox man through and through and used to fix Hardi all the time.

Unless I've missed a reply to this, the main reason I would use marmot or similar over hardie is purely because marmot will help the heat to just come up through tile whereas hardie let's heat through it which wastes money and heat response time.
they both do the job though but other big disadvantage of hardie against marmot is that it more expensive than trimline contractor board I use and takes far more time to fix which adds more cost

 

[Chalker]

Unless I've missed a reply to this, the main reason I would use marmot or similar over hardie is purely because marmot will help the heat to just come up through tile whereas hardie let's heat through it which wastes money and heat response time.
they both do the job though but other big disadvantage of hardie against marmot is that it more expensive than trimline contractor board I use and takes far more time to fix which adds more cost

not heard of trimline. Is it the same as other makes?

 

[jonnyc]

Trimline is a supplier of tiling tools and accesories.they make dukkaboard and also the contractor board.
both are cement faced front and back as marmot,wedi or similar.
i get best price by pallet from trimline although marmot is quite good value.i went off marmot few years back when the started supplying bowed boards. These were made in Egypt and left too long in sun I heard but they may well have sorted that now

 

[Chalker]

Do you rate the boards? Just used some Marmox and was ok, if a little lightweight. Found pcs boards were just as easy to use but were twice the weight and a harder surface.

 

[RDTiling]

Problem as I see it is that as he has not installed the cables he will only certify the connection so the cable installation itself is not certified...

Good shout there Alan. I'll keep that in mind for any future installations.

As as it turns out, customer has decided not to go with UFH. Turns out the brother is a plumber and is going to put a heated towel rail in instead.

 

[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.