Electric under floor heating ??

[liam546]

I am looking to lay under floor heating in my bathroom.

The floor is just wooden floor boards and I plan to lay insulation/backer board, screw down and then lay the loose electric cable. I will then tile with a porcelain tile on the floor.

My question is what is the recommended thickness of insulation board to lay in order to achieve a good U value and to stop heat escaping into the sub floor?

Also can I just hook wire this up to the live in the lighting circuit which is RCD protected?

 

[Taylortwocities]

Follow the maker's instructions.
If you have timber floor, you can overboard with 18mm WBP plywood or something like Warmup® Insulation Board. You won't need both.

A lighting circuit is unlikely to have the current carrying capacity to power the underfloor heating. Take a spur from an RCD protected ring final circuit.

By the way, remember that the project you have in mind is notifiable to yourt local authority. It may be better to have a registered electrician do the sparking and the paperwork. It will be cheaper.\
\

 

[liam546]

Thank you for the advice. I do plan on having an electrician doing the wiring to the socket and thermostat etc.

I have looked at the warmup backer insulation boards which go from 6mm up to 50mm as well as the a product call hardiebacker although I'm not sure this is an insulation board.

I guess my real question is do I go with a 6mm board, 10mm or 50mm? My floor is wooden floorboards on joists.

 

[liam546]

To level my floor initially I've read about taking up floorboards and laying 18mm WBP ply board with wooden shims on the joists to level it.

Would you recommend this?

 

[EFLImpudence]

Is it worth the bother?

Electric UFH isn't exactly wonderful.

 

[liam546]

I don't want my floor to end up being too high and so removing floor boards and replacing with 18mm ply will mean when insulation boards and tiles are laid I'll have a lower floor.

Can I ask why your not keen on electric underfloor heating?

 

[EFLImpudence]

I don't want my floor to end up being too high and so removing floor boards and replacing with 18mm ply will mean when insulation boards and tiles are laid I'll have a lower floor.

It'll still be high

Can I ask why your not keen on electric underfloor heating?

It's expensive to run for little benefit.
It takes a long time to warm.

It doesn't and can't do more than take the chill off the floor.
That may be all you want but how cold will it be without?
You will still put bathmats on the floor insulating it.

I just don't think it's worth it.

 

[liam546]

Thanks again fir comments.

Interesting debate as I've heard many with your view on under floor heating and many that do like it.

If I do go with it I plan to use insulation board to minimise heat loss downwards, to ensure all heat goes up through tiles. In terms of running cost my thinking was I could switch it off if it was costing too much. I do want it to heat bathroom and take chill off tiles. In regards to the finished height of the floor I realise this will be higher than it is currently but I thought if I start my removing floor boards then at least I'd be starting at the lowest point to get the lowest overal height possible.

 

[SimonH2]

I wouldn't want a bathroom floor without either carpet or UFH. Wood is probably "not too bad", but tiled is decided cold under foot. Agreed it's not going to heat the room all that well unless you have it "quite warm" and then lecky UFH will cost a lot to run, but for making a tiled floor comfortable it's "quite nice"