I'm planning to opt for the Hep2o piping system delivered via a Heatbank , unless anyone thinks there are better options.
I'm now at the stage where new well insulated concrete slabs have been laid on the downstairs floors and upstairs is currently bare joists.
I have 3 zones. Upstairs are two small bedrooms only 24m2 in total, downstairs a living area 24m2 and an attached kitchen + bathroom area about 16m2.
I can't seem to find any guidelines for pipe density. Intuitively, I suspect 100m of 16mm barrier pipe will be adequate for the larger areas, perhaps OTT for the upper floor. I'm inclined toward drilling the joists to retain structural strength although I could notch them at this point.
What I think I have to do now is pin the piping to the slab and lay a
50mm screed to cover it with a view toward a ceramic tiled surface, leaving adequate tails to connect to the zone controller.
If I'm heading in the wrong direction, now is a good time to know -)
I have a well insulated new build and I used 2x (almost) 100m loops per
30 sq meter (there were some long runs to get to some of the rooms)..that was tied down to every OTHER bar of the reinforcing mesh in the screed. I think that's about 8" spacing. (200mm) so that should be about 5 meters of pipe for every square meter of floor..I THINK the Polyplumb site reckoned that was 50W/square meter roughly..
I'd say that upstairs is one 100 meter run..thats *just* enough for you...but make sure you plan carefully to use it ALL.
Two is spot on for downstairs as well.
Few things that may be worth considering.
I have no heat in upstairs corridors or landings at all. Enough comes from below to heat them REASONABLY.
*FILL AND PRESSURISE THE PIPE BEFORE SCREEDING. And LEAVE THE PRESSURE ON. You can hire a suitable pump. This is really important to make sure the pipe is never subject to constrictions etc. This almost mandates that you have the pipe and manifold installed and filled BEFORE screeding. Do not screed empty pipe.
If tiling take time to get screed very level. If you c*ck up it will mean expensive levelling compound, or in my case a lot of expensive rapid setting tile cement to raise up tiles over the slumped sections of flooring..it may be worth investigating te sort of 'liquid slurry and vibrator' flooring systems I saw on Grand Designs..wish I'd known abdout that.
Make sure screed is thick enough so you can screw stuff to the floor without unduly worrying about pipes under...pipes tend to go in through doorways in a blockwork house..on the ground floor..you may want thresholds there ..
Site your main thermostat sensibly. I suggest an upstairs corridor or landing ;-)
I didn't UFH my upstairs, which I regret, but had little option with 'exposed' beams and a floor thickness of only about 50mm..With joists at
400mm spacing I'd fill the rafters with 50mm of celotex, and loosely clip the pipes up and down each joist to give an average of one run per
200mm. Worth pressure testing these before the floor goes down as well, but no need to hold pressure up afterwards..try not to screw the flooring into the pipes tho :-)
Especially for the thought on pressurising the pipe. I'd not considered that the pipes might be flattened by screeding. That might have been a very expensive error....
Jeff Might I suggest a few ideas to consider. The 1st being to the type of pipes that you are using. Personaly I would opt for, and have i the past, some pex-al-pex piping since it holds its shape whilst fitting. If you dont have any joints below the screed, and there is no reason why you should, then I wouldn't be overly concerned about pressure testing the system before screeding. I am concerned when you mention a well insulated concrete slab being already present. I am assuming that you have laid the insulation over this concrete slab rather than under it, if you have any more than 100mm total concrete slab thickness above your insulation then the time for heat recovery will be too great- 75mm total is ideal. I used reinforcing mesh once when I did this job as it seemed a good idea and would suggest that nobody in the future does the same, there is a risk of indenting the pipe if you stand on a pipe while laying the concrete, there is no risk if you dont use mesh. Suggested spacings between pipes are anywhere from 125mm to 200mm depending on the heat source. It might be worth giving themalfloor
01738 620400 a quick call for a cost, they are extremely competitive and their manifolds are excellent quality. Another thing to consider before screeding is photographing each room with 50cm markings so that you always know where the pipes are for the future... and also ensure that you dont lay pipes directly under the toilet where you will be wanting to place screws to fix the toilet. Hopefully this is helpful, but if you need any further information then please call me (calum sabey- newark traditional kitchens 01556 690544)
As I recall it was 100mm slab on top of the celotex board, though it may have been less as we were somewhat constrained in getting within architect plans for the proposed floor level. We used heavy duty mesh in the footings for the attached extension but not on the slab.
I'll check out the pipe you mention and the point about the toilet (and other sanitaryware is a good one). I'm already planning to avoid door thresholds by going thru the wall. For the bathroom area which is where the heatbank will be sited I'm anticipating a little heat from that and perhaps I may not need to put much at all under this fairly small area, which will be only large enough for a shower, basin and wc plus the heatbank.
There is no risk if the pipe is pressurised either.
No, depending on the insulative qualities of the room. At the permitted maximum for screed..IIRC about 40C - that IIRC equates to 80-50W/sq meter output.
There is no reason not to use the highest temp you can ..
Bugger. Thats a waste really. You need another layer of insulation on that slab ..as Calum says otherwise its going to take some real time to warm up..I used about 25mm polystyrene in mine....if you can add that and 75mm screed with the pipes in that would be best.
I have had such trouble screwing bogs into tiled floors that the latest one I just followed a tip here..put 4 tile spacers underneath, squirted silicone under, and removed the spacers..Its solid as a rock.
IMHO it is not possible to have a bathroom that is too hot ;-)
Calum here again. My comment on the spacings being decided upon the heat source was that many UFH installations are done by people who are also installing geothermal heating. In that case the temperature is lower and pipes should be run closer together (125mm). I would suggest that you drill a hole *8mm or so) in the concrete to assertain the thickness so far. If it is 50-75mm and you have a good level of insulation below (min 60mm kingspan or similar) then you could get away with a light screed of
25-50mm on top of your pipes. If doing this then make sure you seal your existing concrete before laying the new concrete since your old will no longer be green.
In your situation i would also consider putting more zones in. Think about a zone for each room, its not much more money and gives you more control ie. you probably dont want your bedroom floor to be too warm before you go to bed but you do want living space to be warm. Then you can have a room stat in each room, with your bathroom having an open loop (which is also important to protect your boiler and pump).
Unfortunately most architects stipulate a slab underneath the main slab. In my experience this is not necessary and wastes alot of money. Much better is 100mm of compacted sub base, a vapour barier, 100mm insulation, UFH pipes, 75-100mm concrete. Calum (NewArk Traditional Kitchens 01556 690544)
I agree whole heartedly with the rest. I stuffed in 50mm polystyrene insulation on architects advice: with hindsight 100mm would have been better, and kingspan even better
I was discussing this with my builder chum yesterday and he thought likewise - a lighter screed over the pipes - which will also be covered with heavy ceramic or slate tiles. He also suggested a secondary layer of some thin insulation material. We have 2300 headroom at present so
2250 won't be too bad but we may have to raise the old doorway with a lintel as it's now just about 6 foot.
I know the insulation board is 60 mm thick because I ordered it and saw it go down, though the slab on top is more like 100mm. I can see it because we are just about to lay the DPM for the extension and the edge of the main room is visible. We've more height to play with in the extension and will be laying 75mm insulation there.
I might be able to, but there's no way I'd do it. UFH heating is an abomination - UFH systems that work and are switched on are far worse. Frightful. Still, there are a old codgers who think back to the '70s and still misguidedly think UFH is a new and even worthwhile thing, instead of the crock that it really is.
I just think that they are absolutely ghastly. Very uncomfortable to live with. A great dis-incentive to buy a house with this in, or even visit, when it's turned up. Whether tales of slowness and inflexibility are true I don't know (or even care, really). I just wouldn't have it!
Several that have functioned, unfortunately.
The choice is yours, of course, I'm just saying that I hate it! You may love it to bits!
Well there are tons of visitors here who are delighted with how nice and cosy it is, and ho much better it is not to have ugly dust trapping radiators everywhere.
All I can say is that you cannot have ever experienced a properly implemented system in a well insulated house.
So far you haven't actually said what is at the core of your prejudice..
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.