Will this work?

[Chablais]

I am hoping to install UFH on an existing beam and block floor, but am struggling with the heat loss calcs to work out if it will work, or if I will lose too much heat downwards.

The largest space is an open plan, living, dining and kitchen with a floor area of 64m2, half of the space is open to the pitched roof. 

I calculated a heat loss of 2995W for the combined space

I have limited scope in making the floor build up deeper

My proposal is:-

 

Remove the existing 50mm screed and replace with 40mm PIR and 40mm liquid screed with pipes embedded.

I have access underneath the floor, so proposing to fill the void between the beams with 50mm rockwool as easy to compression fit, then board over with 100mm Kingspan Kooltherm bonded to the concrete beams, taped at joints and foamed at all edges as best I can.

To try to mitigate losses from the floor edges, where they are at external walls, I am fitting 75mm EWI from foundation level to DPC and then 100mm up to eaves.

The P/E is .38 using external walls only

 

Or should I not bother with the 40mm PIR on top as I will end up heating the Beam and Block floor anyway, and concentrate on sealing up the crawl space. It tapers from 1600 to 600mm too large a volume to fill with beads I think. So am laying DPM and lapping and sealing to walls.

If it is worthwhile how do I work out the pipe spacing required to produce enough heat?

Heat will be supplied via a gas combi, but looking at ASHP for future.

Hope someone can help

Thanks

 

 

5918-02A Detail floor plans.pdf

5918-03A Detail sections.pdf