We're currently looking at redoing the bathroom from scratch - those
with long memories might remember my questions about how to box in
pipework a while ago, well, it didn't happen, it just got worse...

Anyway...

It's on the ground floor, solid concrete floor, and is part of a
simple ground floor extension that connects to the rest of the house
via a an ante-space (just wide enough to fit a tumble dryer in, to
fulfil the old requirement of having two doors between a bathroom and
a kitchen.

Raising the floor level an inch or two to insulate prior to laying the
UFH and tiling might be a little restrictive - so the question is,
just how inefficient would UFH on bare concrete be ? (would you even
notice it was installed ?)

On 17/02/2008 11:45, Colin Wilson wrote:

Raising the floor level an inch or two to insulate prior to laying the
UFH and tiling might be a little restrictive - so the question is,
just how inefficient would UFH on bare concrete be ? (would you even
notice it was installed ?)

I installed heating elements under kitchen tiles on an un-insulated
convrete kitchen floor and it's very easy to notice the warmth on bare
feet when it's used.

On Sun, 17 Feb 2008 11:45:09 -0000 someone who may be Colin Wilson
o.uk wrote this:-

Raising the floor level an inch or two to insulate prior to laying the
UFH and tiling might be a little restrictive - so the question is,
just how inefficient would UFH on bare concrete be ? (would you even
notice it was installed ?)

I hope you would notice the increased electricity consumption. Why
try and heat the ground?

Is there any reason to want underfloor heating in the room?



--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

I hope you would notice the increased electricity consumption.

Not too much of an issue on that score, it's only something like
60W/sq meter IIRC - i've had two PCs running 24/7 since about 1995, so
a little more isn't going to make too much of a difference.

Why try and heat the ground?

....building layers of insulation into it would create a step from the
kitchen to the ante-space, and with having a fitted kitchen, it would
be hard to rejig that to accomodate insulation.

Is there any reason to want underfloor heating in the room?

It's the bathroom
It's got a solid floor
It's in an extension, ergo a little colder than the rest of the house

Last but not least, the missus has always wanted it...

Same problem here, I put in 8mm of insulation. I wanted to put in 50 to 75mm
but floor levels would not allow this.

It takes around an hour and a half to realy notice that the heating is on if
you are in bare feet. We have a downstairs bedroom with on suite and a
little hall to the back door all with ceramic tiles with the electric mat
under tile heating.

We only use the shower room when guests are here and only switch it on at
those times. In saying that when it is on, it is lovely if you are walking
on bare feet. If we could not use the stairs and were using the downstairs
bedroom and on suite, I would have the tile heating on no question at all.


there any Is reason to want underfloor heating in the room?

It's the bathroom
It's got a solid floor
It's in an extension, ergo a little colder than the rest of the house

Last but not least, the missus has always wanted it...

Same problem here, I put in 8mm of insulation. I wanted to put in 50 to 75mm
but floor levels would not allow this.
It takes around an hour and a half to realy notice that the heating is on if
you are in bare feet.

Thanks for that, much appreciated - at least it gives me an idea of
how long it takes to warm up under semi-insulated conditions :-)

(we'd probably just end up leaving ours on full time fwiw)

Colin Wilson wrote:
Same problem here, I put in 8mm of insulation. I wanted to put in 50 to 75mm
but floor levels would not allow this.
It takes around an hour and a half to realy notice that the heating is on if
you are in bare feet.

Thanks for that, much appreciated - at least it gives me an idea of
how long it takes to warm up under semi-insulated conditions :-)

(we'd probably just end up leaving ours on full time fwiw)
I have electric underfloor heating in 2 bathrooms - both tile on ply.
150W per sq metre, takes about 30mins/1hr to notice the difference, but
with a thermostat timer very manageable.
The heat does not spread sideways through the tiles , so make sure you
cover everywhere you might stand with the mat - I didnt !

Only adds about 5mm to the thickness of the floor.

Thats a point.
I left a good clearance round the WC and when you stand there having a Pee
in bare feet you are standing on colder tiles. So work out where the WC is
going and in that area disasemmble a bit of the mat and get the wirse to
within 25 mm of where the wc goes. It will make a differance!!!!!

The heat does not spread sideways through the tiles , so make sure you
cover everywhere you might stand with the mat - I didnt !

That Bloke wrote:
Thats a point.
I left a good clearance round the WC and when you stand there having a Pee
in bare feet you are standing on colder tiles. So work out where the WC is
going and in that area disasemmble a bit of the mat and get the wirse to
within 25 mm of where the wc goes. It will make a differance!!!!!

The heat does not spread sideways through the tiles , so make sure you
cover everywhere you might stand with the mat - I didnt !



Further investigation this morning suggests the heat spreads sideways
across a tile reasonably well but not to adjacent tiles across the grout.