How practical / economical is fitting wet UFH under an existing suspended wooden floor?

A friend has just bought a renovated 1900s terrace and is thinking of doing so. He also has a builder about to remove some of the downstairs wall to open up the reception rooms/hallway.

He reckons the upstairs and loft conversion feel warm but downstairs stays quite cool and thinks UFH might improve this.

Does UFH not work best when there's a large thermal mass (i.e. concrete slab)?

In these circumstances, would it improve comfort without necessarily being an improvement economically?

On 21/11/2013 13:07, mike wrote:
How practical / economical is fitting wet UFH under an existing suspended wooden floor?

A friend has just bought a renovated 1900s terrace and is thinking of doing so. He also has a builder about to remove some of the downstairs wall to open up the reception rooms/hallway.

He reckons the upstairs and loft conversion feel warm but downstairs stays quite cool and thinks UFH might improve this.

Does UFH not work best when there's a large thermal mass (i.e. concrete slab)?

In these circumstances, would it improve comfort without necessarily being an improvement economically?

Personally I would prefer the heat to be delivered directly into the
room via a radiator rather than through a wooden floor. Wood being quite
a good insulator which is why it gets used for saucepan handles.

There is quite a wide choice of radiator type things. You are not
limited to the conventional metal panels.

--
Michael Chare

On 21/11/13 13:07, mike wrote:
How practical / economical is fitting wet UFH under an existing
suspended wooden floor?

pretty good really.

A friend has just bought a renovated 1900s terrace and is thinking of
doing so. He also has a builder about to remove some of the
downstairs wall to open up the reception rooms/hallway.

He reckons the upstairs and loft conversion feel warm but downstairs
stays quite cool and thinks UFH might improve this.

Does UFH not work best when there's a large thermal mass (i.e.
concrete slab)?

no. Thtas a fallacy. What you need is nothing more than a high
conductivity path upwards and a low one downwards. Yes concrete conducts
better than wood but concrete is thicker and with a carpet on its still
pretty poor!

Te secret here with suspended wood floor is massive insulation downwards
under the heating coils.

So its

- lift the floor completely
- intstll at least 6" of celotex between joists set down an inch or two
and seal with mastic foam or WHY.
- either use premade foam pipe guides or some way to get hot water pipe
into the gap.
- peressure test pipes.
- relaly floor.
- pressure test again in case you nailed through it
- hook up to new CH circuit and thermostat
- enjoy.



In these circumstances, would it improve comfort without necessarily
being an improvement economically?


Done properly especially with lo thermal inertia wood, its actually very
efficient. IN addition a warm floored room is more evenly heated and so
it feels warmer.


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

On 21/11/2013 13:07, mike wrote:
How practical / economical is fitting wet UFH under an existing suspended wooden floor?

Very, on both counts.

A friend has just bought a renovated 1900s terrace and is thinking of doing so. He also has a builder about to remove some of the downstairs wall to open up the reception rooms/hallway.
He reckons the upstairs and loft conversion feel warm but downstairs stays quite cool and thinks UFH might improve this.

Yes indeed.


Does UFH not work best when there's a large thermal mass (i.e. concrete slab)?

No, I'd suggest the opposite.
Low thermal mass i.e. suspended wooden floor gives much better response
times both from heating up and cooling down. Much more responsive to
room thermostat, more like the response of traditional radiators.

In these circumstances, would it improve comfort without necessarily being an improvement economically?

It would improve both comfort AND economy.

I have 75mm (I think) cellotex with 10mm "fastflow" pipe clipped to that
and a dry sand/cement mix of only about 15mm (not exactly a huge thermal
mass) to assist general heat transfer to floor which is 18mm T&G
flooring chip board (green stuff) screwed to the joists, thin brown
paper sheet to seperate (allow movement) and 15mm engineered flooring
(Kahrs "oak london") floating on top.

If I did it again I would probably use aluminum spreader plates to
transfer heat from pipe to floor rather than faffing around with a thin
dry-mix screed.

If you can run the whole house heating at UFH temps i.e. max 55 degree
especially if upstairs is well insulated it could make a significant
difference to economy but if existing radiators don't offer sufficient
heat at lower temps then run it hotter and let the UFH manifold t/stat
do it's stuff.

I have a load of pictures of when I did it somewhere. Might stick them
up in a shareable album if interested..

Pete@
--
http://www.Water-Rower.co.uk
The "stand on it's end" designer WaterRower
Space saving, quiet, commercially rated and made of wood!

On 21/11/2013 16:22, www.GymRatZ.co.uk wrote:

I have 75mm (I think) cellotex with 10mm "fastflow" pipe clipped to that
and a dry sand/cement mix of only about 15mm (not exactly a huge thermal
mass) to assist general heat transfer to floor which is 18mm T&G
flooring chip board (green stuff) screwed to the joists, thin brown
paper sheet to seperate (allow movement) and 15mm engineered flooring
(Kahrs "oak london") floating on top.

Not saying this is the company to use however it's the company and
method I used. Lots of examples at the following.
http://www.nu-heat.co.uk/s.nl/sc.7/category.22/.f
and my own particular method of choice sort of described above is
detailed as document TSG14 although they are now suggesting 14mm
"Fastflow" which wasn't an option 6 years ago. The rest is much the same
although I also added 100mm or more of rockwool loft insulation UNDER
the celotex to provide a bit more sound insulation in the bedrooms below.

HTH

On Thursday, November 21, 2013 1:07:31 PM UTC, mike wrote:
How practical / economical is fitting wet UFH under an existing suspended wooden floor?

No personal experience but I read that some contractors were getting unsatisfactory results unless they used heat transfer plates between the pipes and floor boards.
The 'staple-up' method wasn't as good.

There's no other reason why it shouldn't work.
Insulation under pipes is required as mentioned above.

On 21/11/13 16:44, wrote:
On Thursday, November 21, 2013 1:07:31 PM UTC, mike wrote:
How practical / economical is fitting wet UFH under an existing suspended wooden floor?

No personal experience but I read that some contractors were getting unsatisfactory results unless they used heat transfer plates between the pipes and floor boards.
The 'staple-up' method wasn't as good.

There's no other reason why it shouldn't work.
Insulation under pipes is required as mentioned above.


What you need to understand is that the heat will always get up there
eventually. If you don't use plates simply use more pipe. In the end
that simply makes the air under hotter, and you get the same heat
transfer. The limit on that is when the air temp approaches UFH pipe
limits. which are only 55C IN SCREED which can crack.


You can calculate hear transfer into the room using standard U values
for wood.

say the desired room is 20C and you have 3/4" of hardwood. And the air
underneath is at say 45C.

I have from building regs a k value of 0.14 for wood, so 20mm of wood
will have a U value of 0.14/0.02 or 7.. so for a temperature difference
of 25 degrees that's 175W/sq meter.

Notably one inch of wood is MORE conductive than 4" of screed..

A typical well insulated room only needs 50W/sq meter. So the wood here
is not the limiting factor. Probably the pipe surface area is.

So add more pipe. I'd personally go for 4" spacing which should give you
around 100W/sq meter.

you can always turn heating down, but unless you run it dangerously hot,
you cant turn an under piped system UP.





--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

"mike" wrote in message
...
How practical / economical is fitting wet UFH under an existing suspended
wooden floor?

A friend has just bought a renovated 1900s terrace and is thinking of
doing so. He also has a builder about to remove some of the downstairs
wall to open up the reception rooms/hallway.

He reckons the upstairs and loft conversion feel warm but downstairs stays
quite cool and thinks UFH might improve this.

Does UFH not work best when there's a large thermal mass (i.e. concrete
slab)?

In these circumstances, would it improve comfort without necessarily being
an improvement economically?


The floor is probably the problem. There will be an air flow beneath it and
likely draughts/air leaks though it.

As a minimum it needs insulating and draught proofing before you start.
Probably best to fit normal radiators rather than UFH.

Alternative is to take up timber floor and replace with concrete (insulation
below) & then UFH.

UFH works best with tiled floors etc (ie no insulation on top.) But plenty
underneath.

On 21/11/2013 13:07, mike wrote:
How practical / economical is fitting wet UFH under an existing
suspended wooden floor?

A friend has just bought a renovated 1900s terrace and is thinking of
doing so. He also has a builder about to remove some of the
downstairs wall to open up the reception rooms/hallway.

He reckons the upstairs and loft conversion feel warm but downstairs
stays quite cool and thinks UFH might improve this.

Does UFH not work best when there's a large thermal mass (i.e.
concrete slab)?

Heating works best when you have proportional control and a low thermal
mass with no insulation between it and the occupants.
However its difficult to do and most of them compromise by having more
thermal mass to slow down changes. Many boilers makers suggest fitting a
buffer (heat store) tank to hold the heat for the UFH so the boiler
doesn't cycle too much.


In these circumstances, would it improve comfort without necessarily
being an improvement economically?



If the UFH is under the floor boards you may want to fit heat spreaders
to get the heat through the wood without having to increase the flow
temperature.
Put plenty of insulation under the heating elements.

You may be better off installing it on top of the floor and covering it
in a new floor if you have the room height to do so. You still want
plenty of insulation under it.

On Thursday, November 21, 2013 4:22:37 PM UTC, www.GymRatZ.co.uk wrote:

I have a load of pictures of when I did it somewhere. Might stick them

up in a shareable album if interested..


I'd like to see them if it's not too much trouble.

I'm slightly surprised at how positive the responses have been - I thought there might be less enthusiasm for retro-fitting in a suspended floor.

On 21/11/13 18:36, mike wrote:
On Thursday, November 21, 2013 4:22:37 PM UTC, www.GymRatZ.co.uk wrote:

I have a load of pictures of when I did it somewhere. Might stick them

up in a shareable album if interested..


I'd like to see them if it's not too much trouble.

I'm slightly surprised at how positive the responses have been - I thought there might be less enthusiasm for retro-fitting in a suspended floor.

UFH gets a bad press because builders don't understand it and cock it up.

uk.d-i-yers are smarter than that. Done well its the best there is.

--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

On 21/11/2013 20:54, The Natural Philosopher wrote:
On 21/11/13 18:36, mike wrote:
On Thursday, November 21, 2013 4:22:37 PM UTC, www.GymRatZ.co.uk wrote:

I have a load of pictures of when I did it somewhere. Might stick them

up in a shareable album if interested..


I'd like to see them if it's not too much trouble.

I'm slightly surprised at how positive the responses have been - I
thought there might be less enthusiasm for retro-fitting in a
suspended floor.

UFH gets a bad press because builders don't understand it and cock it up.

uk.d-i-yers are smarter than that. Done well its the best there is.


Except perhaps for the discomfort to the bum which means you have to
keep moving around, as undergraduate visitors to St Catherine's Oxford
will tell you. (My first experience was in 1967).

On 21/11/2013 18:36, mike wrote:
On Thursday, November 21, 2013 4:22:37 PM UTC, www.GymRatZ.co.uk wrote:

I have a load of pictures of when I did it somewhere. Might stick them

up in a shareable album if interested..


I'd like to see them if it's not too much trouble.

I'm slightly surprised at how positive the responses have been - I thought there might be less enthusiasm for retro-fitting in a suspended floor.


It's an attractive proposition for sure. I was going to put it in when
the living room floor was replaced but was vetoed (by 'er indoors) on
the grounds of it complicating the job.
As it turned out, the room is the warmest in the house, by a distance,
which is chiefly the result (IMO) of 75mm of celotex bewteen the joists,
which probably acts as much by stopping draughts as by true insulation.
So he might save a significant job/cost and get the required outcome of
a warmer room just by insulating.
The only reservation I had/have about the UFH though, is whether the
timber of the floor boards might dry out too much over time (and, of
course, whether that really matters if it's covered).

On 21/11/2013 18:36, mike wrote:
On Thursday, November 21, 2013 4:22:37 PM UTC, www.GymRatZ.co.uk wrote:

I have a load of pictures of when I did it somewhere. Might stick them

up in a shareable album if interested..


I'd like to see them if it's not too much trouble.

I'm slightly surprised at how positive the responses have been - I thought there might be less enthusiasm for retro-fitting in a suspended floor.

No trouble Mike.
I found a folder called HOUSE which has a selection of pictures taken
from when we moved in through the whole gutting, re-wiring, UFH and
other assorted stuff. Hopefully the attached link will work
https://www.dropbox.com/sh/m9ad3681x7hhv3l/1ccz013d0b

All floor work and re-plumbing of copper and UFH was done by myself.
Most of the re-wiring done by our friendly 'lectrician.

Remember this is living area upstairs, bedrooms downstairs so the
individual UFH zone manifolds collect the 10mm pipe together then run
back to the hall/toilet where they drop DOWN into the airing cupboard
below. (Pic. 53 would be this place)

The "album" seems to work on Firefox but the rubbish known as IE10
doesn't have the and arrows.

Any questions let me know though it was quite a while ago I did it.


If you don't have dropbox mine's getting full so the following link will
bung me an extra 500MB if you use it to sign up.
https://db.tt/iHYgHDPD
;¬)

Cheers
Pete@
--
http://www.GymRatZ.co.uk
Gym and fitness stuff of quality.





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In article , www.GymRatZ.co.uk wrote:
Not saying this is the company to use however it's the company and
method I used. Lots of examples at the following.
http://www.nu-heat.co.uk/s.nl/sc.7/category.22/.f

Certainly _don't_ use the stuff Nu-Heat were using around 15 years ago when
my house was built:
http://www.ebuild.co.uk/topic/4371-p...floor-heating/

On 22/11/2013 11:55, Alan Braggins wrote:

Certainly _don't_ use the stuff Nu-Heat were using around 15 years ago when
my house was built:
http://www.ebuild.co.uk/topic/4371-p...floor-heating/

From what I remember it was made by Monsantano ....
That stuff has been long dead..

On Thursday, November 21, 2013 9:52:42 PM UTC, Pet @ www.gymratz.co.uk ;¬) wrote:

No trouble Mike.

I found a folder called HOUSE which has a selection of pictures taken

from when we moved in through the whole gutting, re-wiring, UFH and

other assorted stuff. Hopefully the attached link will work

https://www.dropbox.com/sh/m9ad3681x7hhv3l/1ccz013d0b


Ah, thanks very much for that. Interesting to see a real installation. Will pass that on to my mate who I'm sure will be horrified at the complexity!

On 22/11/2013 21:48, mike wrote:
On Thursday, November 21, 2013 9:52:42 PM UTC, Pet @ www.gymratz.co.uk ;¬) wrote:


https://www.dropbox.com/sh/m9ad3681x7hhv3l/1ccz013d0b


Ah, thanks very much for that. Interesting to see a real installation. Will pass that on to my mate who I'm sure will be horrified at the complexity!

What I would suggest to your friend is if he is planning on staying
there for the next 5+ years then get stuck in and do it, especially if
the floor is going to be lifted to add some form of insulation anyway.

Another significant reason that influenced my decision to do UFH was
that there were only 2 walls realistically suited to having radiators in
the lounge (that originally had large double panel rads. on each wall)
and we took one of those walls away to go open plan leaving no-where to
put the 2nd radiator.

It's expensive (or time consuming if done DIY) but the results were well
worth it (for us at least). I doubt it added anything to the value of
the property because you can't see it and who pays attention to the
heating when looking at a new house.... as your friend has proven unless
viewing the house in the depth of winter (unlikely).

Cheers
Pete@
--
http://www.GymRatZ.co.uk
Commercial Gym Equipment and WaterRowers
Supplier to Rufty Tufty gyms and clubs UK and beyond.



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"Pet @ www.gymratz.co.uk ;¬)" wrote:

a selection of pictures taken
from when we moved in through the whole gutting, re-wiring, UFH and
other assorted stuff. Hopefully the attached link will work
https://www.dropbox.com/sh/m9ad3681x7hhv3l/1ccz013d0b

All floor work and re-plumbing of copper and UFH was done by myself.

What's with the zig-zag copper bridging between the two pipes?

https://dl.dropboxusercontent.com/sh/m9ad3681x7hhv3l/xTj3_EDUeg/pete0033.jpg?token_hash=AAH44m8FKYJ3j-Mul9K1c06PNr1c066c-HcKdAjzZmXHEQ

On 23/11/2013 08:09, Andy Burns wrote:
"Pet @ www.gymratz.co.uk ;¬)" wrote:

What's with the zig-zag copper bridging between the two pipes?

https://dl.dropboxusercontent.com/sh/m9ad3681x7hhv3l/xTj3_EDUeg/pete0033.jpg?token_hash=AAH44m8FKYJ3j-Mul9K1c06PNr1c066c-HcKdAjzZmXHEQ


I knew that would come up.


It was a heat-exchanger experiment.... based on the idea that making use
of residual heat from the return pipe of the "extension" heating loop
that currently goes no-where other than to the garage and back to the
boiler (Plumbed for future expansion of turning garage into habitable space)
to off-load a bit of heat into the dead leg of the kitchen hot water
supply DHW.
It does work to a degree, 5 seconds worth of cold water before a burst
of warm water comes through which then goes cool again for a few seconds
before the boiler heated proper hot water comes through.

So for rinsing off hands etc it does the job perfectly well.

Idea is that heat would travel from hot to cold (large surface area to
pointy).
I just split a length of 22mm pipe and cut some teeth in with tin snips.
Works pretty well given the crudeness of construction and lack of
scientific calculations. That's D-I-Y ;¬)

--
Pete@
http://www.GymRatZ.co.uk
Home and domestic Gym and fitness Equipment.



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