UFH Spreader plate - insulation below?

[Hilldes]

Working through spec for 1st floor UFH with Wunda. Most likely will go for F04 spreader plates fixed to top of posi joists.

 

In the data sheet, the F04 has a layer of EPS immediately under the spreader plate. EPS is supported on battens fixed to the joists. Not keen on additional effort to fix the EPS.

 

Asked if I could omit the EPS as will have 100mm mineral wool acoustic insulation below the spreader plate between each joist. Answer was yes, but essential the mineral wool is immediately below the spreader plate. I'm thinking the mineral wool will lie on the ceiling plasterboard, so will be around 140mm below the spreader plate.

 

Anyone encountered this and found a solution? Any major issue with the mineral wool being some way below the spreader plate?

[willbish]

I guess it depends what heating requirement you need upstairs.

If you've really good insulation levels, air tightness etc etc and minimal heating required having a slightly less than optimal UFH system upstairs isn't going to be the end of the world.

 

[Hilldes]

10 minutes ago, willbish said:

I guess it depends what heating requirement you need upstairs.

If you've really good insulation levels, air tightness etc etc and minimal heating required having a slightly less than optimal UFH system upstairs isn't going to be the end of the world.

 

Thanks @willbish that is my thinking too. We won't need much in the way of heat output.

 

I guess the only downside might be the entire ceiling void will be warm - warming cables, water piped etc.

[willbish]

Won't the ceiling void be warmed from the ground floor anyway? In a low energy house all areas near enough same temperature and UFH flow temps low.

 

I'll shortly be considering this too. I am going to install 4 loops of UFH upstairs despite not really needing any heating upstairs. Aluminium spreaders installed from below. 

 

You've got me thinking now, services or sound insulation next...