A UFH biggy ?? .

[townfanjon]

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 .

 

[ShaunCorbs]

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

 

[Chalked]

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!

 

[Last Plumber]

Mrs Townfanjon and myself look like we have bought a new house

Leaving the land of the White rose?
If you're staying, can I have that passport?

 

[townfanjon]

Leaving the land of the White rose?
If you're staying, can I have that passport?

Hell no , dont be silly , and the passport is priceless .

 

[Sharp Point]

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!

 

[Sharp Point]

I can’t upload an image....damn, says some error

 

[Ric2013]

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.

 

[Sharp Point]

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.

 

[ShaunCorbs]

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

 

[townfanjon]

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 .

 

[townfanjon]

I can’t upload an image....damn, says some error

Have another go pal lol

 

[ShaunCorbs]

Over boards it is then

 

[townfanjon]

Over boards it is then

Erm ... watch this space , not sure yet lol

 

[Sharp Point]

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.

 

[Sharp Point]

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.

 

[ShaunCorbs]

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

 

[ShaunCorbs]

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

 

[rpm]

Leaving the land of the White rose?
If you're staying, can I have that passport?

LP, you would have to dig him up and crowbar his fingers away to get that passport!

 

[Sharp Point]

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

 

[ShaunCorbs]

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

 

[Sharp Point]

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.

 

[Sharp Point]

So it's flexible in its self and not slab like, so hold each end and the middle with move etc yea right

I didn’t understand everything from the comma onwards, holding what each end

 

[Old Account]

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.

 

[Last Plumber]

LP, you would have to dig him up and crowbar his fingers away to get that passport!

He'll die with it in his teeth and a Yorkshire pud in his hand.