UFH pipe options, which is best?

Ruggers · 28 Oct 2020

Could anyone advise with some of these basic UFH questions.
I've been looking at the different pipe available for wet UFH and it seems that pex-A seems to be the one thats rated the highest, for those fitting UFH, is this correct & is there any benefit to using the pert pipe or Al pert or others i've missed?

The UFH will be fit to the ground floor only, there will be 5 heating zones totalling 70m2, the living room totals 24m2 so will require 2 loops. New build block & beam floor with 150mm insulation. I will be running the pipes in myself & someone will commission it when they instal the boiler. Upstairs will be radiators all on a system boiler.

- Once a pipe construction type is chosen, does the brand make a difference?
- Would 16mm pipe at 200 mm centres and 100mm from any walls be suitable?
- Who specifies the screed depth & type?

cross thread · 28 Oct 2020

Contact continental underfloor they will advise you, we have used them several times

Ruggers · 29 Oct 2020

Nothing coming up on a search when i type them in. UFH comes up and is called continal, is this the correct one. They use their own brand stuff?

Ruggers · 30 Oct 2020

Thought on this?

Someone at the home show also said that in your kitchen where you generate heat from the cooker, and a living room where you might have a log burner, it's a good idea to add a floor screed stat as well as the room air temperature stat. These are often used to stop the floor slab overheating, but can be used to make sure the floor doesn't go off totally in that room when cooking for example. If you have an air temperature of 21 degrees set in the kitchen, when cooking it might reach this quickly turning off that zone, it might be an option to set a minimum of 17 degrees on the floor sensor so that them rooms sill maintain minimum heat in the slab for when you turn off the alternative heat source.

It's a bit belt and braces but seemed a good suggestion. Not sure if this would be easy to configure.

muggles · 30 Oct 2020

Pex-al-pex or pert-al-pert would be my choice. It's better quality and easier to work with. 200mm centres should be fine. Go for a liquid screed for best heat transfer. Your screed supplier will advise on depth. Floor screed sensors are a very good idea and not at all expensive - usually around £10-15 each

Ruggers · 30 Oct 2020

muggles said:
Pex-al-pex or pert-al-pert would be my choice. It's better quality and easier to work with. 200mm centres should be fine. Go for a liquid screed for best heat transfer. Your screed supplier will advise on depth. Floor screed sensors are a very good idea and not at all expensive - usually around £10-15 each

Thanks, do you think for the price of the screed sensors it's a good idea to have them in all 4/5 zones or just the two rooms with extra heat sources?

I know the screed sensors are usually for the purpose of preventing overheating, and in the suggestion I was given, to use them to prevent the slab temperature dropping too much if the other heat source is active. But can they be used for both high and low alongside the air temp. or just high or low only?

muggles · 30 Oct 2020

Yes, put them in every zone. It's much better to have them and not need them, than to need them and not have them. Some floor coverings require the temperature to be limited - they aren't just there to protect the screed.

I've never heard of them being used as a low limit but presumably such a feature is available with certain controls

Mr Chibs · 31 Oct 2020

I recently had wet ufh, didn’t bother with floor sensor, as it’s only in one room. I will be using a thermostat to control temp.

if memory serves, my plumber advised against the aluminium Type pipe, said it was hard work.
I went polypipe, on a big coil you just have to get used to working with it, as it’s a bit springy and want to do its own thing.

I fitted it myself, into red floor trays.

Screed depth for me was dictated by the rest of the floor level through the house.
Ended up being around 65/70mm.
I choose liquid screed, and very happy with the flatness.

Polypipe ufh guide is quite good even if you don’t use their system.

Good luck.

Ruggers · 31 Oct 2020

Mr Chibs said:
if memory serves, my plumber advised against the aluminium Type pipe, said it was hard work.
I went polypipe, on a big coil you just have to get used to working with it, as it’s a bit springy and want to do its own thing.

I fitted it myself, into red floor trays.

Screed depth for me was dictated by the rest of the floor level through the house.
Ended up being around 65/70mm.
I choose liquid screed, and very happy with the flatness.

Polypipe ufh guide is quite good even if you don’t use their system.

Good luck.

Thanks for the info. I'm sure all require some form of oxygen barrier within the pipe and thought this had to be aluminium, but different pipes can handle different max temperatures & pressure, and as you say, some form better than others. This is where i'm unsure. I've called some suppliers but many just say it's all the same which didn't feel was a satisfying answer. Europe seem to only use Pex A, not pert. You never have the temp up high anyway but it was more of a safe guard incase the blending failed.

I'm expecting a similar screed depth but probably going with the pipe direct to insulation with tacker clips.

When the screed was poured, did you or the builder need any polishing floats or machines or does it just level it's self?
I'll check out the polypipe.
I've spoke to a supplier called VPS but need to check many others.

Mr Chibs · 31 Oct 2020

Well, like I said it was my first install.

I thought the trays would be a better idea, yes adds a bit to cost, but it did allow me to fine tune the coil design, so you can lift out the pipe and redo any bits you are not happy with.

having done that, I done think i could have easily managed using the clips unless you have a tacker.
Also it’s a pig to get out the clips without buggering up The insulation. I used about 5 clips here and there, where I’d double up the trays.

when the screed was laid, a laser level got the level, then tripods set to this level, then in comes the pump, and before you know it, you have a floor...

The floor is then dappled with a big bit of metal tubing, to get the level as flat as possible. It surprised me how level.

A day and a half later, I got a scrapper out, to take off the Laitance... yes they don’t tell you this at first... but it was pretty quick. It’s the top layer that dries powdery, and needs to be removed.

You only need floats if you want a polished finished.

I went for snail layout, two coils.

HTH.

Ruggers · 31 Oct 2020

The trays definitely make it look easier. Even the rails you can lay in a row at the ends where the bends are.
Is that two loops or one loop of pipe used for that room? Did you find with the snail layout the whole floor is the same temperature?

Just regular tubing to move it around where it needed to go then let it self level?
I've seen people use big floats on poles and also makeshift versions of round pipe on poles but that was for concrete slab not screed.

Mr Chibs · 1 Nov 2020

Haven’t fired it up, due to other works holding things up.

It’s a two loop design.
I looked at the strip clips, but think you would have to go serpentine design, as you won’t be able to secure at the corners, unless you clip it.

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UFH pipe options, which is best?

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