Wet Underfloor Heating with Timber Joists (1st Floor) + Eng Wood

[Steve111222]

Hi,
We are renovating our house - its currently been gutted and we are thinking of putting Wet Underfloor heating in the whole house and currently weighing up the options. The ground floor will definitely be UFH (concrete floor so will be 100mm celotex + pipes + screed + flooring.) and we are debating weather to put it upstairs as well.

1. The first floor is made of timber joists - has anyone had any experience of UFH here and what would the floor build-up need to be?
   
   I have heard that it needs battens + insulation between the joists. then run pipes, but i am not sure how much insulation and what needs to cover the pipes before laying the floor
   
   
2. Any recommendations for specific wet underfloor systems?
   
   
3. I am quite keen to go for a wood floor, but i'm not sure how effective it will be with UFH...has anyone got Wet UFH with Engineered Wood Floor? What size / thickness planks did you use and did you have any issues with the floor getting too hot / bowing / cracking?

 

[Anstiss Ltd]

My suggestion is to speak to the companies that sell this stuff.

I've used continental under floor heating

They will give you lot of option will discuss it all with you and if you can give them a sketch a full plan upstairs and down.

If you buy from them they will then give you a cad layout too

 

[Steve111222]

Hi yep I have reached out to a few. They all say that eng wood is fine, just that it takes longer to heat up, but then will retain the heat longer once it is warmed up.

There's two options for the timber floor from what i can tell - either insulation + spreader plate + pipe or foil-backed insulation which has grooves cut in for the pipes to run along; so will weigh up the options and take it from there.

 

[Anstiss Ltd]

Continental do a product called OneBoard that is what I'm fitting upstairs.

It's a 22mm structural board with the spreader plates built in to the top surface. You cover it with a 6mm board so total floor is 28mm

This reduces warm up time and means you can lay your final structural floor before the underfloor heating goes in

 

[Screech20]

I’ve been looking into UFH too, and have been looking at the screening in between the joists option. Have any of the suppliers mentioned that?

 

[Steve111222]

Continental do a product called OneBoard that is what I'm fitting upstairs.

It's a 22mm structural board with the spreader plates built in to the top surface. You cover it with a 6mm board so total floor is 28mm

This reduces warm up time and means you can lay your final structural floor before the underfloor heating goes in

Ok cool - I'll take a look at that, thanks. did you still need to put insulation in between the joists though i take it?

 

[Steve111222]

I’ve been looking into UFH too, and have been looking at the screening in between the joists option. Have any of the suppliers mentioned that?

Hi - did you mean Screeding in between the joists? one of them did list that, but they said you need to check if the joists would be able to cope with the extra weight of the screed, which I'm not too sure how to check; so not sure if i will go down that route.

 

[Anstiss Ltd]

Ok cool - I'll take a look at that, thanks. did you still need to put insulation in between the joists though i take it?

Not actually fitted yet, but the plans do show insulation between the joists so as to maintain correct zoning of rooms

 

[Anstiss Ltd]

Hi - did you mean Screeding in between the joists? one of them did list that, but they said you need to check if the joists would be able to cope with the extra weight of the screed, which I'm not too sure how to check; so not sure if i will go down that route.

I looked at this option using an aggregate called lytag it's like an expanded clay ball so makes the screed lightweight.

But I would have had to increase my joist to c24 in some places and decreased the centres to 300 cc in one room with long spans, this made it unviable and labour intensive.

I do agree though that you get a better heat distribution.