DIY overlay boards for ufh

[J Sid]

to much time down south John and you have a developed a sense of humour 😱

 

[EatingSnakes]

Ah I wrongly presumed your pipes were already fitted into pregrooved boards, like a polypipe type of system so the whole floor was already 16mm higher than the base, you need some sort of insulation under the pipes or you'll be wasting heat into the subfloor.. As it is it'd take a lot more than three of four bags of leveler, more like 10..

The concrete slab is already insulated underneath with 100mm PIR.

I was planning on putting overlay boards on top of the concrete and tiling directly on top of that. I was going to do DIY overlay boards, but now that I've realised I need to bring the floor up by 26mm, overlay boards won't cut it. Might as well reap the advantages of a screed. My calculations suggest I will need 6 bags of the Mapei screed :S

where are the pipes coming from? Please don't tell us from your radiator run

No, the pipes will be coming from a manifold although I have been given the option of a Danfoss TRV by my plumber. This basically feeds into the radiator flow. The idea is that because it is such a small space (4.1 sq m or ~30m pipe run) the boiler pump will be more than adequately be able to cope with it.

 

[Andy Rhodes]

So your plumbers saying you can run the system via your radiator valve because that's what a Danfoss TRV is a normal radiator valve. Is the manifold linking up direct from the boiler

 

[J Sid]

😀I'm not a plumber , but I wouldn't want radiator temp water flowing though my ufh pipes

 

[Andy Rhodes]

if the boiler is controlling the ufh it would have to be on to heat the floor up wouldn't it, because a boiler only has 2 setting on it heating & water or water only, I'd possible look at installing an electric ufh system preferably the matting one

 

[EatingSnakes]

nah. It's not an actual radiator TRV.

It's something like this:
https://www.polypipe.com/housing/po...rlay™/polypipe-ufh-temperature-limiting-valve

That one is made by polyplumb specifically for underfloor heating, it only allows the maximum appropriate temperature for UFH. I hear the Danfoss ones are better because it measures all of the temperature inside of the valve and you dont need the probe.

Anyway, back to the topic.
Will the Mapei screed work?
Does anybody have any experience in making fibre reinforced screeds for thin (26mm) ufh screeds.

Thanks for all the help thus far.

ES

 

[Spare Tool]

I'm no plumber either but surely that valve doesn't reduce rad water temperature it just opens and closes letting bursts of pipping hot radiator temperature water through, its not actually regulating the water temp? @Wayne Brown
The Mapei Reno screed is perfect but I still think you require some insulation under the pipes, even if its just 6 or 10mm Jacoboard or similar..what you board with is saving on leveler so hardly a difference in cost..

 

[Andy Rhodes]

You may have to fit anti fracture matting on top of the screed before tiling to compensate for the extra heat your system is going to generate

 

[Boggs]

You can use the Danfoss FHV valves when extending systems up to 10 sqm but I believe you need a minimum of 75mm screed.

 

[Time's Ran Out]

to much time down south John and you have a developed a sense of humour 😱

Away from this pool tomorrow after 6 weeks! They’ve run out of mosaics.
I’ll be back.
But going down to Reigate for a week thanks to @stonetiler who has helped me fill in some time.
Wife doesn’t think it’s funny!