Interesting...

As some may remember, I'm fixing a 1950's bungalow, with a solid concrete
uninsulated ground floor.[1]

I'd ruled out insulation, believing it had to go *under* the screed (or
slab). Turns out I was wrong, when I came across Marmox board - a
polystyrene insulating board faced with fibre glass/cement which can
*allegedly* be tiled straight onto (compressive load 30 tonnes/m2 according
to manufacturer).

I then ruled out UFH, believing electric was the only option in this case.

Ho hum: While I was looking to see if there was anything cheaper than
Marmox, came across this:

http://www.floorheater.co.uk/

"Easy panel" is the product of interest - 25mm polystyrene with grooves to
take 12mm or 16mm PEX pipe for wet underfloor heating. 30t/m2 compressive
load, 15t/m2 prolonged.

Looks like the company is importing a Swedish, or at least Scandanavian
product. Claims you can tile straight onto it. Had a response to an email
earlier to them, just waiting to see the cost of the insulated 25mm board
(non insulated products are priced on the website).

*If* it compares favourably to Marmox + cost of rads+vertical rads + fan
convectors (which I won't then need) I shall have to give it serious
consideration.

I'm not asking advice, because I'd be amazed if anyone here has actually
installed this stuff (please speak up if you have or know someone!) -
thought it might be of interest though...

If the quote looks reasonable, I'll ask for an offcut to look at and do a
test bond to the floor to see if it looks like it will actually handle the
job. Really don't want to be putting tiles down and taking them up again
before I'm dead, if I can help it ;-

Cheers

Tim

[1] Repeated my boss's measurements on Sunday: 1 thermometer 0.7m above
floor, another 0.05m above floor. 4C difference - and my feet were freezing
off through socks and shoes. Granted the building is only minimally heated
for frost protection (I brought the air upto 12C with half a central
heating system and a gas fire over 6 hours) - so the slab is extra cold,
but all the same... It's probably going to be a cold floor if I just tile
over it.

On Mon, 05 Jan 2009 21:56:30 +0000, Tim S wrote:

http://www.floorheater.co.uk/

Interesting. I've added a link to the Wiki UFH page
http://wiki.diyfaq.org.uk/index.php?...rfloor_Heating.

Have you priced up getting the existing floor dug out and replaced with
proper insulated slab with embedded UFH? No system using thin insulation on
top of an existing uninsulated slab is going to give similar efficiency.
Plus is the existing slab properly DPCed?

On a job I've been working on the builders did just this - to an area of
about 7m x 3m total. Took 2 labourers about a day to dig it out, maybe
half a day to level the area with concrete, maybe another half day to lay
polythene DPC + 100m polystyrene (+ UFH piping), another day or so to
concrete. They were mixing up the concrete in a barrowmix: on a bigger job
with readymix one would obviously save some time over that.

--
John Stumbles

I've got nothing against racists - I just wouldn't want my daughter to marry one

Hi,

John Stumbles coughed up some electrons that declared:

On Mon, 05 Jan 2009 21:56:30 +0000, Tim S wrote:

http://www.floorheater.co.uk/

Interesting. I've added a link to the Wiki UFH page
http://wiki.diyfaq.org.uk/index.php?...rfloor_Heating.

Have you priced up getting the existing floor dug out and replaced with
proper insulated slab with embedded UFH?

No - partly because the thought of the amount of work, mess and expected
cost scared me (even if I didn't do the job!). Perhaps it might be less bad
than I thought if I did price it, but it's too late now - I've made the
decision not to do that and I'm too single minded to change my mind at this
stage as work's started (which is probably a good thing IMHO with a large
project). The idea of adding any insulation to the surface was an
opportunistic one as it doesn't add much to the work and doesn't break the
basic plan. The UFH is even more opportunistic - but I'm not commited until
I prove it to not be an utterly stupid thing to do. At least the extra work
for UFL plumbing is offest by no radiator plumbing.

If I think for one minute that sticking stuff under floor tiles is going to
make them less than long lived, I'll scrap this and go back to the original
plan as robustness and longevity is a higher priority for us.

No system using thin insulation
on top of an existing uninsulated slab is going to give similar
efficiency.

Agreed. The whole thing started off due to discussion at work about how
effective 25mm of Jablite was compared to nothing. Of course, there'll be
more losses with UFL as it runs at 27C as opposed to the floor tiles
getting to maybe 18C with insulation but no UFH. There is an element of a
previous discussion suggesting losses away from the external walls may be
less due to the ground retaining some heat - I'll never calculate that
though. But a worse case calculation based on the board's k-value assuming
a certain (constant) ground temperature will be easy enough.

Plus is the existing slab properly DPCed?

No. None whatsoever. The email I got back from teh company said to use
cementous tile adhesive to stick the panels down as what they'd normally
recommend isn't very good in the damp. But I'm looking at a couple of coats
of Aquaseal (Aqua Stop IIRC) onto the concrete / screed anyway for good
measure. The floor has survived 50 years with a variety of floor coverings
including vinyl, clay tiles and wood tiles with no obvious problems so I'm
not particularly concerned. No mushrooms on the walls, though that may be
due to what looks like a chemical DPC that's been injected some time ago
(found the injection holes behind some skirting I pulled off last week).


On a job I've been working on the builders did just this - to an area of
about 7m x 3m total. Took 2 labourers about a day to dig it out, maybe
half a day to level the area with concrete, maybe another half day to lay
polythene DPC + 100m polystyrene (+ UFH piping), another day or so to
concrete. They were mixing up the concrete in a barrowmix: on a bigger job
with readymix one would obviously save some time over that.


That's interesting. The cost break point for me for 95m2 is about 2500 quid.
That is the combined cost of Marmox board (stronger jablite in effect) and
all the rads, soem vertical rads (not cheap but a necessity due to room
shapes) and a couple of Myson fan convectors (also not cheap, but
required).

I wonder why no-one's done a marmox type board based of PIR foam? Would seem
to be an obvious product, unless there's a technical difficulty... Did scan
the Celotex and Kingspan sites, but there's nothing identical in
application.

I'll come back when I have some more info from them.

Cheers

Tim

In article , Tim S
writes

I wonder why no-one's done a marmox type board based of PIR foam? Would seem
to be an obvious product, unless there's a technical difficulty... Did scan
the Celotex and Kingspan sites, but there's nothing identical in
application.

I'm not convinced that composite boards are such an advantage in
flooring applications, I think I'd prefer a layer of easily laid PIR
foam sheets carefully sealed at joints, followed by your Marmox with
staggered joints and bonded down with contact adhesive.

PIR foam sheets rated for use in floors are available.
--
fred
BBC3, ITV2/3/4, channels going to the DOGs

Looks like the company is importing a Swedish, or at least Scandanavian
product. Claims you can tile straight onto it.

One claim that strikes me as taking the proverbial was...

"Whereas an electrical system can easily be damaged irreparably by a
lightning strike or power-surge, The Box system utilises a water pipe
to heat the floor, meaning it's safe from any such damage."

I haven't heard of any internal underfloor electric heating suffering
from a direct lightning strike personally, but i'm sure it's no more
likely than a muppet drilling fixings into a wet floor system.

Oh, and then there are the (minor) discrepancies, like...

"It has been established through careful testing that the PEX water
pipe used in the system could last, in use, for over 400 years."

"In special tests carried out by the Royal Institute of Technology,
Stockholm, it is estimated that our water pipe could last, in use, for
up to 500 years!"

Colin Wilson coughed up some electrons that declared:

Looks like the company is importing a Swedish, or at least Scandanavian
product. Claims you can tile straight onto it.

One claim that strikes me as taking the proverbial was...

"Whereas an electrical system can easily be damaged irreparably by a
lightning strike or power-surge, The Box system utilises a water pipe
to heat the floor, meaning it's safe from any such damage."

I haven't heard of any internal underfloor electric heating suffering
from a direct lightning strike personally, but i'm sure it's no more
likely than a muppet drilling fixings into a wet floor system.

Oh, and then there are the (minor) discrepancies, like...

"It has been established through careful testing that the PEX water
pipe used in the system could last, in use, for over 400 years."

"In special tests carried out by the Royal Institute of Technology,
Stockholm, it is estimated that our water pipe could last, in use, for
up to 500 years!"

I noticed that. But PEX is PEX, so I'm happy with that bit - other people
use it for UFH.

It's the ability of the panels not to deform and to remain stuck that I'm
most concerned about.

It's very hard finding people who've tried this stuff - Marmox is nigh on
impossible to verify and that's a more common product AFAICS...

Cheers

Tim

Tim S wrote:
Colin Wilson coughed up some electrons that declared:

Looks like the company is importing a Swedish, or at least Scandanavian
product. Claims you can tile straight onto it.

One claim that strikes me as taking the proverbial was...

"Whereas an electrical system can easily be damaged irreparably by a
lightning strike or power-surge, The Box system utilises a water pipe
to heat the floor, meaning it's safe from any such damage."

I haven't heard of any internal underfloor electric heating suffering
from a direct lightning strike personally, but i'm sure it's no more
likely than a muppet drilling fixings into a wet floor system.

Oh, and then there are the (minor) discrepancies, like...

"It has been established through careful testing that the PEX water
pipe used in the system could last, in use, for over 400 years."

"In special tests carried out by the Royal Institute of Technology,
Stockholm, it is estimated that our water pipe could last, in use, for
up to 500 years!"

I noticed that. But PEX is PEX, so I'm happy with that bit - other people
use it for UFH.

It's the ability of the panels not to deform and to remain stuck that I'm
most concerned about.

It's very hard finding people who've tried this stuff - Marmox is nigh on
impossible to verify and that's a more common product AFAICS...

Cheers

Tim

Maybe best bet is get a piece, put a tile on it, stand on it and have
someone measure it accurately. Any movement and forget it.


NT

coughed up some electrons that declared:



Maybe best bet is get a piece, put a tile on it, stand on it and have
someone measure it accurately. Any movement and forget it.


NT

Sound advice - then I can make sure the DPM/adhesive/board/adhesive/tile
bonds are all happy.

Waiting for a price by email - my ISP crashed for the entire day so email
for me is backed up on other people's servers

Cheers

Tim

Tim S coughed up some electrons that declared:


Waiting for a price by email - my ISP crashed for the entire day so email
for me is backed up on other people's servers

OK. The ISP lost their ATM uplink to BT's 20C network. Ow.

But it's back, I have the email and it looks like:

Marmox 20mm and EasyPanel 25mm [1] are *very* similar in price.
PEX pipe and manifolds are comparable to the rads/convectors I would need.

So - insulation vs insulation+UFH is comparable. Either is 2k more expensive
than doing neither (what I originally intended).

I think it would be worth getting a sample of the EasyPanel for
examination - after I run a crude heat loss calculation...

[1] The PEX pipe is 16mm, so even in 25mm, some of the pipe will have a lot
less insulation between it and the floor slab. 20 vs 2

Cheers

Tim

Tim S coughed up some electrons that declared:

Ho hum: While I was looking to see if there was anything cheaper than
Marmox, came across this:

Couple of factual followups, for anyone reading this later from google...

I've just handled a piece of 10mm (ish) "Warmup" under-tile insulation
panel, down at Topps Tiles place. It appears identical to Marmox.

It is *very* robust. The surface is as hard as rock and the softer core foam
(it's foam rather than squidged white stuff like jablite) feels very robust
in the face of tearing or compression. I would have no qualms about using
this to achieve basic insulation under tiles - though I'd go for at least
20mm if practical.


http://www.floorheater.co.uk/

Just had a message back from an old friend in Sweden. This product is really
made by these people: www.floore.se

He says that he's checked and a couple of the big DIY sheds out there are
carrying this product, so we conclude it probably has basic credibility at
least. I'll follow up when i get my mitts on the sample I've been promised.

Cheers

Tim