UFH onto timber floors

[Dave H]

Looking for advise, I always use Heat Mat underfloor heating, and on timber floors fix onto 10mm Marmox either screwed or stuck and screwed, doing job for builder where I specified this, but architect has made
enquiries with Heat mat,and says they are happy to go straight onto timber with flexible tile adhesive. Talked to Ardex technical guys and they won't recommend without backer board. Any opinions greatly
appriciated

 

[bugs183]

Hiya with all respect to the tech guys at Heat Mat they are underfloor heating salesmen, not tilers.
I never tile direct to wood, i always use an uncoupling membrane or Marmox, i tend to use Marmox now much more.
I'd stick to your guns on this one Dave, use Marmox, glued and screwed.

 

[Ajax123]

Technically heat mat are correct in that their system can go directly onto timber but that has nothing whatsoever to do with it. The tile floor cannot. It needs to go on a backer board. You are the tiler therefore its your name on the job and your rules. As bugs says they are there to sell underfloor heating and you are there to do the tiling. Your bit takes precedence.

 

[Dave H]

Thanks bugs & Ajax, exactly what I thought, have to stand your ground sometimes, have told builder to ask architect to give me a written spec with
adhesive recommendation or do it my way, be interesting to see what he comes up with! as always when you talk to technical at UFH companies they will not
generally name specific products, they just want to sell their heatmats.

 

[jonnyc]

Thanks bugs & Ajax, exactly what I thought, have to stand your ground sometimes, have told builder to ask architect to give me a written spec with
adhesive recommendation or do it my way, be interesting to see what he comes up with! as always when you talk to technical at UFH companies they will not
generally name specific products, they just want to sell their heatmats.

dave , this is where it gets very confusing for us sometimes.
i am sure that technically there is no problem with heat mats working even though set directly on to ply base . the problem in my eyes and always has been is that i would be worried about direct heat to the wood base underneath. the heat mat manufacturers dont see this as their problem.
this is why i always use dukkaboard or similar under electric mats over timber subfloors and always have done over using ditra that does the job but still lets heat through the floor m possibly affecting the timber base.
i have had no end of issues with being able to spec wf some really quirky underfloor heat systems over last few years

 

[Dougs Third Go]

deffo use backer boards as you'll also be flooding the heat mat with slc prior to tiling.

 

[Uheat - Keith]

Good morning, here we always say:-

For a HEATING system, most times you need 160w/m2 in normal rooms, 200w/m2 in a Conservatory etc.
With a TILED floor finish area, you need a 160w/m2 system (200w/m2 etc as above)
For a WOOD floor base, 100w/m2 Underfloor Heating System output maximum.


We have:- Elektra MD100 Underfloor Heating Mat for installing on to load bearing, firm, timber based floors. This system is from our Warm Floor range (secondary heat) and may not be a full heating system.

Elektra MD160 / MD200 Underfloor Heating Mat for installing on to concrete based floors or Ekoboard insulation boards or Construction boards (Marmox etc) where the floor finish is to be Tiles / Slate / Stone / Marble / Porcelain etc.

We stock a large range of Underfloor Heating Systems so we can cover everything, but as some of you say, some UF Heating companies will sell you anything.

Sometimes, some projects just do not have enough depth to install boards of any type, so we have MD100 on the shelf for these jobs.
Some companies are just box movers and do not have a full and correct solution for everyone, so will try and sell anything to get their sale.

Warm regards, Keith.

 

[Dave H]

UFH-timber floors

Good morning, here we always say:-

For a HEATING system, most times you need 160w/m2 in normal rooms, 200w/m2 in a Conservatory etc.
With a TILED floor finish area, you need a 160w/m2 system (200w/m2 etc as above)
For a WOOD floor base, 100w/m2 Underfloor Heating System output maximum.


We have:- Elektra MD100 Underfloor Heating Mat for installing on to load bearing, firm, timber based floors. This system is from our Warm Floor range (secondary heat) and may not be a full heating system.

Elektra MD160 / MD200 Underfloor Heating Mat for installing on to concrete based floors or Ekoboard insulation boards or Construction boards (Marmox etc) where the floor finish is to be Tiles / Slate / Stone / Marble / Porcelain etc.

We stock a large range of Underfloor Heating Systems so we can cover everything, but as some of you say, some UF Heating companies will sell you anything.

Sometimes, some projects just do not have enough depth to install boards of any type, so we have MD100 on the shelf for these jobs.
Some companies are just box movers and do not have a full and correct solution for everyone, so will try and sell anything to get their sale.

Warm regards, Keith.

Thanks for replying Keith,

I have not used your products, so will have a look the next time, have always been happy
with heat mat, I no Devi also do a 100w mat for timber floors, which they and you say are
suitable for timber floors, where as I see it the problem lies, is that adhesive manufacturers
will not guarantee their products for this, and Ufh suppliers will not give a specific product
as a specification, so it is left to the fixer to take a chance on fixing without backer boards
and hope floor doesn't move, or stick to his guns use backer board.

 

[Time's Ran Out]

Today's plywood has so much moisture content that even 100w mats will have it moving in all directions, even if you prepare all the joints! So IMHO it must be covered with something before tiling.

 

[Dave H]

Totally agree timeless john, it just hard getting the message across to buiders/architects/clients, when they are being told by UFH suppliers that its fine to go straight onto timber!