Wet Underfloor Heating for Conservatory with wooden floor

[Dave Blake]

I'm considering using wet underfloor heating in our newly installed conservatory. It will be an extension of the existing gas central heating system (radiators in rest of house) driven by an on-demand gas boiler (no water tank).

The conservatory is 4m x 3m, glass/dwarf walls on 2 sides, was designed to be a warm living room (e-glass, high spec, insulated etc.) and to building regs. It will have a suspended wooden floor (joists and boards NOT concrete slab) because the garden level is much lower than the house and we want the floor at house level. However this not constructed yet so heating can be included into the design.

How viable is underfloor heating in this situation? Or should I just install a radiator (using precious wall space)? Any recommendations for products and suppliers (considering DIY since did all the building work)? Useful web sites? Will underfloor heating work?

Advise, experiences, possible problems and suggestions welcome. Dave

[The Natural Philosopher]

Its definitely on, but not (as) cheap or easy (as in a screed).

Since you are starting fromn scratch. its better than most tho.

Problems will be.

(i) You need GOOD insulation downwards. If you rae using a concrte subfllor I would be inclined to actually build up a solid floor using hardcore sub base, then usual metnods of smoothing, followed by DPM, insulation (50-75mm polystyrene) followed by a screed with teh pipes in it.

Even if you lay a suspended floor just over the top of that, it may be easier than e.g. infilling your joists with insulation, and laying pipes over that. The pattern of contra rotating spirtals that gives the most even heating really doesn't fit in with parallel joists.

(ii) UF and wood floors are NOT happy bedfellows. You will need to use narrow planks, pre shrunk to very low humidity, or 'engineering' wood floors, and either lay fully floating or expect some gapping warping and cupping.

If its a modern style you want I would 100% recommend what I did - screeded floor-with-pipes and real wood engineering type surface.

If you really want a suspended floor feel, it can be done, but expect to have to adjust the odd plank and/or sand bits down after the first year.

Ther is no problem by the way, in filling up an extension floor to get it up to level. Usually the foundation spoli is used to get it roughly right...and any surplus bricks, slabs, bits of dead rate etc etc...are just bunged in and tamped down before casting the first slab :-)

Or should I just

[Dave Blake]

Thanks for your suggestions. Unfortunately building up a solid floor brings problems here (although I can see the advantages too). I have an under-croft beneath the conservatory which is then built on top a block and beam platform. I don't fancy the loading of filling the

340mm space between "floor" and platform with hardcore etc. It was designed to take a single story domestic load but not extra tons of concrete on the platform! And I do like the suspended floor feel. But it is good to know the pitfalls.

One doubt I have is whether any UFH will be able to generate sufficient heat for the room. It was designed to maximise warmth, but it is still a conservatory with lots of glass not a traditional building. I am trying to do some basic heat loss calcs on what the heat requirements could be but that is always speculative. Can anyone tell me if they use UFH in a conservatory how warm it is?

Dave

[Andrew]

OSMA do 22mm 8 * 4 chipboard panels with 10mm plastic pipes fitted into them with heat spreaders - check out their website