Floor boards- Ply or insulation board?

[MTiler]

Hi Peeps

Im quoting on a job and the customer is thinking of having electric UFH. The floor is floor boards so am I better off plying the floor or using insulation boards (and what thickness)? Ive read conflicting views on this and my head hurts!
I plan to put slc on top of the UFH mat.
The customer plans to get it themselves but I'll point them in the direction of UHeat.

cheers

missyT

 

[mikethetile]

depends how much deflection there is in the floor, if there is deflection then its wise to overboard, if theres little or no deflection then insulation boards will be fine

 

[MTiler]

That makes sense but Ive read that ply isnt ideal with UFH because the heat can cause it to move.

missyT

 

[TrumpersUnited]

Hi Peeps

Im quoting on a job and the customer is thinking of having electric UFH. The floor is floor boards so am I better off plying the floor or using insulation boards (and what thickness)? Ive read conflicting views on this and my head hurts!
I plan to put slc on top of the UFH mat.
The customer plans to get it themselves but I'll point them in the direction of UHeat.

cheers

missyT

I'd use 10mm PCS boards or marmox, glue and screw boards down with screws and washers supplied. then i would lay heating mat and level over with a flexible leveler and use a good SPF to fix tiles

 

[White Room]

What tiles are you fixing

 

[MTiler]

Customer not sure yet but wont be bigger than 300 - 400s.

missyT

 

[diamondtiling]

When you say floorboards are they chipboard flooring or old floorboards? I would want to replace with 18mm ply and add extra strength with noggins etc, 10mm marmox on top for the best insulation properties. Can you work with these heights?

 

[MTiler]

Theyre old floor boards, which seem relatively secure. I'll be screwing them down before over laying with Ply or insulation board. Ive warned the customer of the extra height and as he is having new units put in that can be taken into consideration.

missyT

 

[diamondtiling]

Mapei fibreplan would be my choice of SLC Missy T

 

[Sean Page]

I'd screw 6mm hardibacker boards down, not forgetting SPF on the floorboards first to take up any voids. Then UFH, SLC etc