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Discuss A UFH biggy ?? . in the Plumbing Jobs | The Job-board area at PlumbersForums.net

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townfanjon

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Mrs Townfanjon and myself look like we have bought a new house , it wants a fair bit of work and I am seriously considering UFH everywhere . Its not 100% finalised yet but should be within a day or two .
Floor is suspended timber ( so not ideal ) and its a bungalow as well, so a pretty large area , I have seen the low-pro pipe system and wondered if any of you have tried it.
Thanks in advance for any thoughts and opinions .
 
Insulation below the joists/ infill

Two option if you can have a bit of extra height then use overboards if not use the alu spreader panels etc
 
As Shaun says, take the boards up and insulate. Then either go for spreader plates and cover with fermacell gypsum floor boards. Only trouble doing this, is that the joists can be unequal distances apart and that plays havoc with your pipe centres.
I’ve used lopro and it works well. You will still need to remove the floorboards and insulate. But then cover with green chipboard. Then install the lopro. You will need a lot of their self levelling, and will be quicker to get somebody with a screed pump to do it. A bungalow could use 4 pallets of the stuff!
 
Don’t use spreader plates, they’re expensive and a waste of time....as you’ve got to insulate it anyhow, I can’t stress about proper 100mm insulation, that overlay stuff is crap to. I’ve used the below method now on three houses and works as good as screeded ufh. Lath along the joists with roofing lath and put 100mm PU insulation across and staple your loops to the insulation and then dry screed 25mm deep to top of joists.... job done!
 
I found the spreader plates needed to be made tighter on where the pipe ought to go to allow a proper grip on the pipe and proper heat conduction. Of course, you need to do this before fitting the plates to the joists. You can trim the plates down to size if need be.

Bogrodder - why are the plates a waste of time? They do seem to spread the heat to some extent. I don't understand what you mean about having to insulate anyway, and how that is related to the use of or lack of use of plates.

Personally, I have issues with the way we think about underfloor heating. We say that modern, low water content, radiators are good because they have a quicker response time. Then we say that UFH is good because it has a huge thermal mass (especially if you screed instead of using plates).

So low thermal mass = quick response = good.

And high thermal mass = slow response = good.

To me this seems bonkers.
 
They’re a waste of time as, they’re very expensive item to purchase and you’ve got to insulate underneath anyhow. They take
I found the spreader plates needed to be made tighter on where the pipe ought to go to allow a proper grip on the pipe and proper heat conduction. Of course, you need to do this before fitting the plates to the joists. You can trim the plates down to size if .

That is another reason they’re a waste of time, the surface contact with the aluminium is probably 60%, so will be very inefficient. At least was dry screed you have near 100% surface contact.
 
And did you consider the extra weight with a screed and as it's timber it will flex but the screed won't and could crack
 
Thanks to all thus far , the house is too big for spreaders plates , I have them in the bathroom and they are ok , but not a full house .
Personally I have never heard of a screeded floor on top of a suspended timber floor .
 
Over boards it is then
 
And did you consider the extra weight with a screed and as it's timber it will flex but the screed won't and could crack
shaun why do you seem to always seem to make a habit of diving in nose first, on subjects you seem to nish about.
 
And did you consider the extra weight with a screed and as it's timber it will flex but the screed won't and could crack

You can stand on 100mm PU foam support across laths, the screed is a dry weak mix at 25mm thick.
 
shaun why do you seem to always seem to make a habit of diving in nose first, on subjects you seem to nish about.

Your kidding right
 
You can stand on 100mm PU foam support across laths, the screed is a dry weak mix at 25mm thick.

Guess you didn't read what I said

I said about the joists flexing, cement doesn't so will likely crack
 
Guess you didn't read what I said

I said about the joists flexing, cement doesn't so will likely crack

Dry weak screed mix doesn’t doesn’t bond like floor screed, it’s stays loose so won’t be able to crack
 
Dry weak screed mix doesn’t doesn’t bond like floor screed, it’s stays loose so won’t be able to crack

So it's flexible in its self and not slab like, so hold each end and the middle with move etc yea right
 
Here’s the method I use, that is a well documented method to do it. You can see that screed mix is barely enough to cover the pipes, much cheaper/quicker way to retro fit ufh between joists.

ABDB3156-6B9F-4917-AC63-FA8D8D3A6F23.jpeg
 
If I could suggest, uheat offers a great kit of ufh. The low profile gypsum boards are fantastic and very very good. You will not raise the floor much about 18mm plus whatever you put on top. I would highly recommend either stone or tile finish. You will not lose any heat any the floor stays longer warm and in the summer it gives a nice cool effect. If you use wooden floor you may lose about 22-25watts on a meter square as far as I remember. If there is no option above floor then only option below and I would do it in the same way as @bogrodder has explained. It is a very good and effective way of laying ufh.
 
That Passport you showed us is definitely priceless.
One day..........I will venture across the moorlands and find one of those for myself. Then I will live amongst thee and learn your plans for taking over us.
Sneaky people who have their own passports for their own County.
 
Bit late coming onto this thread however the two most mentioned systems seems Screed Infill and Retrofix panels. We offer both solutions. Which system you use all depends if your joists can accept the extra 20kg/m2. The screed placed on top is a Drymix – 8:1 damp sand/cement biscuit mix, 20-25mm thick. The retrofix system is a 18mm gypsum panel which can be laid directly onto screed or floorboards and then tiled over without any additional layers. I've attached specifications of both systems.
Dropbox - UltraSlim.jpg
Dropbox - UDry.jpg
 
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