UFH for Ground Floor House - Old Part and New Extension

UFH for Ground Floor House - Old Part and New Extension

Author
Discussion

richie9648

Original Poster:

19 posts

50 months

Friday 21st February 2020
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Hi

First post here and lurking for a while...…….

Just finalising plans for our kitchen and dining extension and looking at getting a wet UFH heating across the whole of the ground floor.

It is 1930s semi and it is a big area to cover and we are looking to put Karndean down as well....now I am getting a bit confused as to what and how the UFH should. I am 99% sure that the old part of the house has a suspended timber floor.

How would I go about having UFH across the whole ground floor and ensuring its level as well between old and new parts of the house? I have been looking at something called the JK UFH system and also Nu-Heat and Polypipe.

Also any issues with having the manifold in the garage as its cold in there.....this is where the boiler is and will be after the build.

Any helpers.....??

Equus

16,883 posts

101 months

Friday 21st February 2020
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richie9648 said:
How would I go about having UFH across the whole ground floor and ensuring its level as well between old and new parts of the house?
confused

You would calculate the finished floor level of the existing timber floor, once you'd added UFH to it, and you'd build the floor in the extension to match that.

anonymous-user

54 months

Saturday 22nd February 2020
quotequote all
As Equus says.

I’m just about to do similar with existing suspended timber, existing solid and a new solid extension.

I called NuHeat and provided them with my plans they did all the calculations for me on what products I need across the different floor types and costs. It’s actually very simple when you get into it.

Andeh1

7,110 posts

206 months

Saturday 22nd February 2020
quotequote all
As above, also no issues with manifold in the garage providing when away from home for winter hols it doesn't freeze. Unlikely though tbh. Wouldn't hurt to build an insulated cupboard around it if it could be a risk.

silversurfer1

919 posts

136 months

Saturday 22nd February 2020
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As the others said easy enough to work our floor levels and no problem putting the manifold in the garage.

One thing to consider is the floor construction of the existing to the new and the thermal expansion of each, normally you would put your UFH tubes within the screed however it may be worth looking at an overlay system to go over both floors for a seamless finish that wont suffer cracking where the two different floors meet

SS


anonymous-user

54 months

Saturday 22nd February 2020
quotequote all
silversurfer1 said:
As the others said easy enough to work our floor levels and no problem putting the manifold in the garage.

One thing to consider is the floor construction of the existing to the new and the thermal expansion of each, normally you would put your UFH tubes within the screed however it may be worth looking at an overlay system to go over both floors for a seamless finish that wont suffer cracking where the two different floors meet

SS
I was advised by NuHeat to use an overlay system with a self-levelling compound on the existing timber and solid floor and then a traditional in-screed for the new AND then use a de-coupling membrane to minimise the cracking of the finished tiled floor.

C Lee Farquar

4,067 posts

216 months

Saturday 22nd February 2020
quotequote all
One thing I (unintentionally) got right with my UFH was to put a manifold in the kitchen cupboard that we use for the crockery.

Certainly takes the chill off the plates in the winter.


anonymous-user

54 months

Saturday 22nd February 2020
quotequote all
C Lee Farquar said:
One thing I (unintentionally) got right with my UFH was to put a manifold in the kitchen cupboard that we use for the crockery.

Certainly takes the chill off the plates in the winter.
That's potentially the cheapest warming drawer ever!

037

1,317 posts

147 months

Saturday 22nd February 2020
quotequote all
As a builder of domestic extensions I have used the polypipe 18mm overlay system many times including my own home. Level the concrete floor to the same height as the existing floor boards ( good idea at this point to check the existing floor levels)
Then simply overlay the whole area. Good idea to get the overlay boards 1/2 way on the transition from suspended floor to concrete floor. Use 60mm concrete screws to save you plugging and screwing.
It’s a great system with quality components

C Lee Farquar

4,067 posts

216 months

Saturday 22nd February 2020
quotequote all
garyhun said:
That's potentially the cheapest warming drawer ever!
Plates are currently 23 deg. Not quite warm enough but helpful when you have a wife who doesn't see the importance of warm plates.

richie9648

Original Poster:

19 posts

50 months

Monday 24th February 2020
quotequote all
garyhun said:
As Equus says.

I’m just about to do similar with existing suspended timber, existing solid and a new solid extension.

I called NuHeat and provided them with my plans they did all the calculations for me on what products I need across the different floor types and costs. It’s actually very simple when you get into it.
Thanks Gary - any idea what the height increase would be on the existing timber floor?

Also, just so I am not confuding things......I would need some insulation in between the joists, fit the flooring back?, install the UFH (nu-heat or similar), screed on top, plywood and then karndean flooring......is that correct???

anonymous-user

54 months

Monday 24th February 2020
quotequote all
richie9648 said:
garyhun said:
As Equus says.

I’m just about to do similar with existing suspended timber, existing solid and a new solid extension.

I called NuHeat and provided them with my plans they did all the calculations for me on what products I need across the different floor types and costs. It’s actually very simple when you get into it.
Thanks Gary - any idea what the height increase would be on the existing timber floor?

Also, just so I am not confuding things......I would need some insulation in between the joists, fit the flooring back?, install the UFH (nu-heat or similar), screed on top, plywood and then karndean flooring......is that correct???
There’s two different systems that NuHeat use for an example.

One will raise the floor level by 15mm and the other 22mm. Which one you use depends on the insulation performance of your house. The 22mm product provides more heat output than the 15mm.

Yes you insulate between the joists and then you either put a self levelling compound over and then fit your final floor (for the 22mm system which runs in plastic egg box type system) OR for the 15mm option you fit your floor directly to the gypsum panels that contain the UFH Pipes.

anonymous-user

54 months

Monday 24th February 2020
quotequote all
The question for me is whether I run the pipes in the screed for the new extension or simply use the over floor solution that will be used elsewhere.

Running the same means that I’ll have similar warm up and cool down times throughout the property but I won’t be able to take advantage of the thermal mass of in screed pipes.

Decisions, decisions.

richie9648

Original Poster:

19 posts

50 months

Monday 24th February 2020
quotequote all

037

1,317 posts

147 months

Monday 24th February 2020
quotequote all
How many M2 are you covering? I got a good price today for around 50m2 from the Underfloor Heating Store

richie9648

Original Poster:

19 posts

50 months

Monday 24th February 2020
quotequote all
I am looking at about 150m2

KurtKlaus

36 posts

121 months

Tuesday 25th February 2020
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Interesting thread. I've been told that UFH in new-built part of downstairs extension will be considerably cheaper than on suspended wooden floor. This means 75% of new kitching/dining will cost same as other 25% which are part of already existing 1930s building. Is it a need for insulation that drives up the cost?

anonymous-user

54 months

Tuesday 25th February 2020
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KurtKlaus said:
Interesting thread. I've been told that UFH in new-built part of downstairs extension will be considerably cheaper than on suspended wooden floor. This means 75% of new kitching/dining will cost same as other 25% which are part of already existing 1930s building. Is it a need for insulation that drives up the cost?
Those % figures are potentially misleading.

If your entire UFH system is £4K then £1k for the new and £3k for the old seems reasonable. If you’re looking at a total of £40k then £10k v £30k sounds very expensive for the suspended timber part.


dhutch

14,388 posts

197 months

Tuesday 25th February 2020
quotequote all
C Lee Farquar said:
One thing I (unintentionally) got right with my UFH was to put a manifold in the kitchen cupboard that we use for the crockery.

Certainly takes the chill off the plates in the winter.
I like it!

dhutch

14,388 posts

197 months

Tuesday 25th February 2020
quotequote all
Equus said:
confused

You would calculate the finished floor level of the existing timber floor, once you'd added UFH to it, and you'd build the floor in the extension to match that.
rofl

Presumably to install wet UFH on a suspended floor tends to involve raising the level of the floor? Which then has implications for doorways and height to the first step of the stairs? Thin pipe systems?

Or is it more common to lift the floorboards and have the insulation and pipework in below that?