Hi all.
Im just about to install the floor in my new ensuite 2.5x2.5 square metres.
The floor is suspended and part of it will be a shower area.
I am going to tile it.
I read some info on underfloor plastic heating pipe[HEP 20 underfloor].
Looks a reasonably cheap system £50 for 70 metres approx.
My big reservation is---- I am told anything less than two layers of 18 mil
exterior ply under floor tiles in a bathroom is asking for tile cracks.
Can underfloor hot water heating work 36mil below the tiles.

tom patton wrote:
Hi all.
Im just about to install the floor in my new ensuite 2.5x2.5 square
metres. The floor is suspended and part of it will be a shower area.
I am going to tile it.
I read some info on underfloor plastic heating pipe[HEP 20
underfloor]. Looks a reasonably cheap system £50 for 70 metres approx.
My big reservation is---- I am told anything less than two layers of
18 mil exterior ply under floor tiles in a bathroom is asking for
tile cracks. Can underfloor hot water heating work 36mil below the
tiles.

Why would anyone want underfloor heating in a bathroom?
The conventional rad in a BR sports less problems.

--
Sir Benjamin Middlethwaite

"
Why would anyone want underfloor heating in a bathroom?
The conventional rad in a BR sports less problems.

The bathroom is on a south facing wall 600 feet above sea level in
Scotland.
The tiles could be very cold in winter.
I was raised in a house where ice formed inside the windows in winter--this
has made me yearn for the soft life--.
Surely if the Romans had heated tile floors its possible for us---although
they did have slaves to keep the system supplied with fuel--.

On Tue, 27 Dec 2005 17:44:48 GMT, "tom patton"
wrote:


"
Why would anyone want underfloor heating in a bathroom?
The conventional rad in a BR sports less problems.

The bathroom is on a south facing wall 600 feet above sea level in
Scotland.
The tiles could be very cold in winter.
I was raised in a house where ice formed inside the windows in winter--this
has made me yearn for the soft life--.
Surely if the Romans had heated tile floors its possible for us---although
they did have slaves to keep the system supplied with fuel--.


The slave trade is banned, but many people are effectivly still
slaves. I am sure many slave trading compaines from the empire days
still exist doing something entirley different, and may be persuaded
to go back to their old ways.

I will have UFH in my batroom, but as its so small, I am not going to
use water to heat it.

Rick

tom patton wrote:
"
Why would anyone want underfloor heating in a bathroom?
The conventional rad in a BR sports less problems.

The bathroom is on a south facing wall 600 feet above sea level in
Scotland.
The tiles could be very cold in winter.
I was raised in a house where ice formed inside the windows in
winter--this has made me yearn for the soft life--.
Surely if the Romans had heated tile floors its possible for
us---although they did have slaves to keep the system supplied with
fuel--.

I don't have tiles in my bathroom, so don't know about the tiles being cold
as I would of thought it would be a disaster zone the tiles being slippy as
you get out the shower/bath? plus a nightmare should you have problems with
the electrics and any piping that would be underneath the floor?

--
Sir Benjamin Middlethwaite

On Tue, 27 Dec 2005 17:57:17 GMT, "The3rd Earl Of Derby"
wrote:

tom patton wrote:
"
Why would anyone want underfloor heating in a bathroom?
The conventional rad in a BR sports less problems.

The bathroom is on a south facing wall 600 feet above sea level in
Scotland.
The tiles could be very cold in winter.
I was raised in a house where ice formed inside the windows in
winter--this has made me yearn for the soft life--.
Surely if the Romans had heated tile floors its possible for
us---although they did have slaves to keep the system supplied with
fuel--.

I don't have tiles in my bathroom, so don't know about the tiles being cold
as I would of thought it would be a disaster zone the tiles being slippy as
you get out the shower/bath?

That is a matter of choosing suitable tiles that do not present a
slippery surface when wet. Alternatives such as vinyl are generally
rather yukky and the UK is about the only country I know where people
still put carpets in bathrooms.


plus a nightmare should you have problems with
the electrics and any piping that would be underneath the floor?


That is why a piped system is probably a safer bet than an electric
one. Barring mechanical damamge to the pipe, it is unlikely to fail.

--

..andy

tom patton wrote:

My big reservation is---- I am told anything less than two layers of 18 mil
exterior ply under floor tiles in a bathroom is asking for tile cracks.

As long as the correct (slightly flexible) adhesive is used you can get
away with a little less - a total floor thickness of 25mm or so ought to
be ok (3/4" floor boards with 9mm ply over for example)

Can underfloor hot water heating work 36mil below the tiles.

Should do.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

The3rd Earl Of Derby wrote:

you get out the shower/bath? plus a nightmare should you have problems with
the electrics and any piping that would be underneath the floor?

You have the (often simpler) solution of going up through the ceiling below.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

tom patton wrote:

The tiles could be very cold in winter.
I was raised in a house where ice formed inside the windows in winter--this
has made me yearn for the soft life--.
Surely if the Romans had heated tile floors its possible for us---although
they did have slaves to keep the system supplied with fuel--.


The floor of my wetroom has tiles on 40mm wedi board on 18mm ply. No
undefloor heating but the tiles seem well insulated by the styrofoam
core of the Wedi board and get quite warm when the shower is running.



--
David Clark

$message_body_include ="PLES RING IF AN RNSR IS REQIRD"

The3rd Earl Of Derby wrote:

tom patton wrote:
Hi all.
Im just about to install the floor in my new ensuite 2.5x2.5 square
metres. The floor is suspended and part of it will be a shower area.
I am going to tile it.
I read some info on underfloor plastic heating pipe[HEP 20
underfloor]. Looks a reasonably cheap system #50 for 70 metres
approx. My big reservation is---- I am told anything less than two
layers of 18 mil exterior ply under floor tiles in a bathroom is
asking for tile cracks. Can underfloor hot water heating work 36mil
below the tiles.

Why would anyone want underfloor heating in a bathroom?
The conventional rad in a BR sports less problems.

Hypocaust http://www.romans-in-britain.org.uk/...al_heating.htm

- the Romans knew how to build a bath room



--
--
zaax

On 28 Dec 2005 00:46:05 GMT, "zaax"
wrote:

The3rd Earl Of Derby wrote:

tom patton wrote:
Hi all.
Im just about to install the floor in my new ensuite 2.5x2.5 square
metres. The floor is suspended and part of it will be a shower area.
I am going to tile it.
I read some info on underfloor plastic heating pipe[HEP 20
underfloor]. Looks a reasonably cheap system #50 for 70 metres
approx. My big reservation is---- I am told anything less than two
layers of 18 mil exterior ply under floor tiles in a bathroom is
asking for tile cracks. Can underfloor hot water heating work 36mil
below the tiles.

Why would anyone want underfloor heating in a bathroom?
The conventional rad in a BR sports less problems.

Hypocaust http://www.romans-in-britain.org.uk/...al_heating.htm

- the Romans knew how to build a bath room

They still do...


--

..andy

Many thanks for all your suggestions.
The most interesting was the roman design with the incentive that I could
easily get the twigs needed to provide the heat for free.
There are two downsides to this---
1 my wife would object to taking her turn to feed the underfloor fire when
it was my turn for a shower---jolly unsporting.
2 the 2 foot height requirement needed for the underfloor ducting is beyond
the available space in my 1974 bungalow.

tom patton wrote:
Hi all.
Im just about to install the floor in my new ensuite 2.5x2.5 square metres.
The floor is suspended and part of it will be a shower area.
I am going to tile it.
I read some info on underfloor plastic heating pipe[HEP 20 underfloor].
Looks a reasonably cheap system £50 for 70 metres approx.
My big reservation is---- I am told anything less than two layers of 18 mil
exterior ply under floor tiles in a bathroom is asking for tile cracks.
Can underfloor hot water heating work 36mil below the tiles.

Do you intend to insulate under the heating pipes? if you fix the
heating pipes to foil backed insulation this should reflect the heat
upwards. When ufh is fitted on a solid floor a 50mm screed is applied
over the top and then a floor covering etc over that, it seems to work
ok although some earlier postings suggested that ufh can be slow to
react. How are you going to control the ufh? it may be an idea to have
it on its own programmer /thermostat so the bathroom could be heated
earlier / later than the rest of the house.

In article , tom patton
writes

Can underfloor hot water heating work 36mil below the tiles.

My bathroom has one sheet of 18mm ply (and floorboards) below the tiles.
It's not actually underfloor heating as such, but the flow and return
pipes from the boiler (28mm) run under the bathroom floor, and do a good
job of taking the shriek factor out of walking on them in bare feet in
winter.

Why would anyone want underfloor heating in a bathroom?

The bathroom is the room that most benefits from underfloor heating. This is
because:

(a) cold tiles barefoot feel uncomfortable.
(b) spills evaporate off more quickly.
(c) the large warm surface area provides radiant heat that is particularly
effective when naked and wet.

Christian.

Christian McArdle wrote:
Why would anyone want underfloor heating in a bathroom?

The bathroom is the room that most benefits from underfloor heating.
This is because:

(a) cold tiles barefoot feel uncomfortable.
(b) spills evaporate off more quickly.
(c) the large warm surface area provides radiant heat that is
particularly effective when naked and wet.

Christian.

I'm sorry but a normal rad will heat the BR in no time, as for cold feet
wear flipflops till you get in&out of the bath/shower.

I can only see problems...
Warpage of the wood underneath tiles resulting in tiles coming away from
cement fixer?

--
Sir Benjamin Middlethwaite

The3rd Earl Of Derby wrote:

I'm sorry but a normal rad will heat the BR in no time,

No one was suggesting it would not...

as for cold feet
wear flipflops till you get in&out of the bath/shower.

The whole point of UFH in this situation is to create a more comfortable
environment for users of the bathroom - without needing to tit about
with flip flops. The fact that spils evaporate faster also imrpoves the
safety of the basthroom as slips are less likely.

I can only see problems...
Warpage of the wood underneath tiles resulting in tiles coming away from
cement fixer?

Its not rocket science - UFH is pretty tried and tested technology and
is very frequently used in just these circumstances without any problems.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

(a) cold tiles barefoot feel uncomfortable.
(b) spills evaporate off more quickly.
(c) the large warm surface area provides radiant heat that is
particularly effective when naked and wet.

I'm sorry but a normal rad will heat the BR in no time,

Yes, but it will provide much less radiant heat, so will be less effective
at heating a wet person, even when heating to the same air temperature.

as for cold feet wear flipflops till you get in&out of the bath/shower.

I would do no such thing. That would be a major inconvenience.

I can only see problems...
Warpage of the wood underneath tiles resulting in tiles coming away from
cement fixer?

Use a good flexible tile adhesive such as Ardex Ardu-Flex 7001 Timber
System. Ensure that the pipe temperature is nice and low to avoid excessive
expansion/contraction. Don't use anywhere near the maximum mixing
temperature.

Christian.

"The3rd Earl Of Derby" wrote in message
. uk...

I'm sorry but a normal rad will heat the BR in no time, as for cold feet
wear flipflops till you get in&out of the bath/shower.

Why not keep your dressing gown on as well, then there's no need for heating
at all!

;-)


--

J B

On Tue, 27 Dec 2005 16:31:28 GMT, tom patton wrote:

Hi all.
Im just about to install the floor in my new ensuite 2.5x2.5 square metres.
The floor is suspended and part of it will be a shower area.
I am going to tile it.
I read some info on underfloor plastic heating pipe[HEP 20 underfloor].
Looks a reasonably cheap system £50 for 70 metres approx.
My big reservation is---- I am told anything less than two layers of 18 mil
exterior ply under floor tiles in a bathroom is asking for tile cracks.
Can underfloor hot water heating work 36mil below the tiles.

Sure. But two issues...
you may have less resistance to heatflow dowwnwards, and end up with an
over ceiling heater :-) Use lots of insulation underneath the pipes..as
much as possible.


Unless you run at very high temperatures, the insulation above may limit
the actual heat output. This won;t cause loss of efficeincy in terms of
burning more fuel - just taht the return temps will be higher.

Suggest this OK if you double up on pipe conecntration.

On Tue, 27 Dec 2005 17:57:17 GMT, The3rd Earl Of Derby wrote:

tom patton wrote:
"
Why would anyone want underfloor heating in a bathroom?
The conventional rad in a BR sports less problems.

The bathroom is on a south facing wall 600 feet above sea level in
Scotland.
The tiles could be very cold in winter.
I was raised in a house where ice formed inside the windows in
winter--this has made me yearn for the soft life--.
Surely if the Romans had heated tile floors its possible for
us---although they did have slaves to keep the system supplied with
fuel--.

I don't have tiles in my bathroom, so don't know about the tiles being cold
as I would of thought it would be a disaster zone the tiles being slippy as
you get out the shower/bath? plus a nightmare should you have problems with
the electrics and any piping that would be underneath the floor?

U/F heated tiled bathrooms are luxury beyind belief in cold climates.

Point is I must build the whole interior of the ensuite so putting
underfloor heating in is a small part of the whole project.
The only thing that concerns me is that it will be worth the 3 extra days
work installing it.
I am thinking of using Hep20 UFH pipe with a temp control on the exit side
using the HEP20 regulator.
Floor build up will be--
Insulation between the rafters under the pipe with industrial foil below the
insulation topped off with 2 layers of 18 mil ply- screws on the upper layer
at 4 inch centers.Using Italian tiles about £35 a square metre.
Will the boiler feed water temp be to high or can I just feed it thro the
system- it will travel 15 metres before it reaches the ensuite and pass 8
radiators en-route.

Use a good flexible tile adhesive such as Ardex Ardu-Flex 7001 Timber
System.
Ensure that the pipe temperature is nice and low to avoid excessive
expansion/contraction. Don't use anywhere near the maximum mixing
temperature.

Christian.

Will the boiler feed water temp be to high or can I just feed it thro the
system- it will travel 15 metres before it reaches the ensuite and pass 8
radiators en-route.

Far too hot, unless the whole house is underfloor powered by a dedicated
boiler on low flow temps. You'll need a pump/mixing valve. Otherwise, apart
from burnt feet, you'll find the wood flexes loads and you'll have cracks in
the grout or even the tiles.

Also, you seem to think that the hot water passes through each radiator on
its way to the bathroom. Whilst that may be true of a 60 year old setup,
such an installation would only be found in the National Museum of Plumbing.
Most systems installed since Hitler's bunker run the pipework in parallel,
so each radiator gets the full flow temperature.

If you really do have an ancient serial plumbed system, you will need to
replace it before installing the underfloor system.

Christian.

Will the boiler feed water temp be to high or can I just feed it thro
the
system- it will travel 15 metres before it reaches the ensuite and pass
8
radiators en-route.

Far too hot, unless the whole house is underfloor powered by a dedicated
boiler on low flow temps. You'll need a pump/mixing valve. Otherwise,
apart
from burnt feet, you'll find the wood flexes loads and you'll have cracks
in
the grout or even the tiles.

Oh dear my hopes for warm feet have been dashed---

I am not installing a separate pump and mixing valve just for the
ensuite--enough trouble with the present 1974 cental heating crap pipework
as it is--drawing air into the pump-needs redesigned---
electric UFH is much to expensive to install/run for me.

Also, you seem to think that the hot water passes through each radiator on
its way to the bathroom.

Nope quite clear on that.
Just extended the main circuit for 3 extra rads--waiting to see if the
boiler will cope--it should on paper---.
Just discovered wonderfull HEP20 plastic pipe--by by copper---hopefully
forever.
My last drunken plumber managed to get 18 leaking soldered joints out of the
22 he made!!.

I am not installing a separate pump and mixing valve just for the
ensuite--enough trouble with the present 1974 cental heating crap pipework
as it is--drawing air into the pump-needs redesigned---
electric UFH is much to expensive to install/run for me.

How big is the en-suite?

I'm planning to lay electric around 80W/m2 in mine. At approximately 1
square metre for the entire floor space in the room, it will cost less to
run than an old style light bulb and I'll just run it on a 1 hour boost
timer. It'll be great for winter Delhi belly without freezing the feet.

Just discovered wonderfull HEP20 plastic pipe--by by copper---hopefully
forever.

Yes, good stuff. Not too keen on pushfit joints (I prefer compression), but
I like the pipework for concealed locations. So easy to thread between
joists.

My last drunken plumber managed to get 18 leaking soldered joints out of
the
22 he made!!.

Bloody hell, I've never managed to ******** up a copper joint. Could be not
be bothered to clean or flux or something?

Christian.

how big is the en-suite?
10 square metres approx.
But the kit will cost about £500 and Im not convinced that an electric
element will last all that long underfoor.
250volts plus drains with a shower above-Im not convinced it will have much
of a life--but--80 watts/metre squared will be.8 killowatt--its tempting---.

I'm planning to lay electric around 80W/m2 in mine. At approximately 1
square metre for the entire floor space in the room, it will cost less to
run than an old style light bulb and I'll just run it on a 1 hour boost
timer. It'll be great for winter Delhi belly without freezing the feet.



My last drunken plumber managed to get 18 leaking soldered joints out of
the
22 he made!!.

Bloody hell, I've never managed to ******** up a copper joint. Could be
not
be bothered to clean or flux or something?

That was about 10 years ago before I retired.He put together a complicated
15 mil cold hot water system below the kitchen sink-did all the work in
situ-very restricted--I now know he should have fabricated the pipework on a
bench then used a couple of compression fittings in situ.I took him home 10
miles-before-turning the water on-naturally he did not test the job!.
My present brickie and sparkie are real pros and make the job look
easy--just waiting on the plasterer--he gets bored on holiday!!----the one
trade I will never master I even manage to get a wall socket patch
wrong--plastering is a real art--in my opinion--a good plasterer can hide
many sins-not that it applies to my extension its a real belt and braces
job--the building inspector took one look at the retaining straps and was
well impressed--you ve even tied them to the wall!!.

On Wed, 28 Dec 2005 16:24:54 -0000, "Christian McArdle"
wrote:


My last drunken plumber managed to get 18 leaking soldered joints out of
the
22 he made!!.

Bloody hell, I've never managed to ******** up a copper joint. Could be not
be bothered to clean or flux or something?


Lead free solder !

And I'm not sure the non-toxic, non-acid flux is much cop nowadays.

DG

tom patton wrote:

But the kit will cost about ï½£500 and Im not convinced that an electric
element will last all that long underfoor.

You can get ready made kits that take care of the complexities of doing
it with a CH fed system. For example:

http://www.screwfix.com/app/sfd/cat/...35309&ts=09644

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

10 square metres approx.
But the kit will cost about £500 and Im not convinced that an electric
element will last all that long underfoor.

You should get it cheaper than that. You should be looking around the 300
quid mark for 80W/m2 over 10m2.

Christian.

On Wed, 28 Dec 2005 14:40:27 GMT, tom patton wrote:

Point is I must build the whole interior of the ensuite so putting
underfloor heating in is a small part of the whole project.
The only thing that concerns me is that it will be worth the 3 extra days
work installing it.
I am thinking of using Hep20 UFH pipe with a temp control on the exit side
using the HEP20 regulator.
Floor build up will be--
Insulation between the rafters under the pipe with industrial foil below the
insulation topped off with 2 layers of 18 mil ply- screws on the upper layer
at 4 inch centers.Using Italian tiles about £35 a square metre.
Will the boiler feed water temp be to high or can I just feed it thro the
system- it will travel 15 metres before it reaches the ensuite and pass 8
radiators en-route.


Matey.

If you are only doing an ensuite, then just arrange for e.g. a longish
arrangement of a loop of copper pipe under the floor, and stick a motorised
valve and a thermostat on it. In fact the plastic MAY be OK as well.

You can go a bit higher temp wise if you are not in screed, and the pipe is
not too close to the woodwork.

Especially if you tap into the return side of the CH circuit where temps
will be a little lower.


The thing about the temp reduction stuff is that its necessary for screeded
floors to prevent cracking. I think my water goes underfloor at 45C or
thereabouts.

If I were doing this on an unpstairs room. I'd do the following.

1/.remove floorboards

2/. lay about 2" of celotex, or white EP foam if you are cheapskating,
between the joists on the downstairs ceilings

3/. Lay a loop of pipe - probably copper to be able to do the tight bends
down alomgside each joist and nack up alongside the adjacent one in the
same gap. Keep spacings about 2" from the joists if possible, and use more
white foam/celotex to insulate joists from the pipework.

4/. Since I am the sort of person I am, rather than notch every joist to
make the pipework connect, I'd bring it all up and run along a skirting,
and box in later. Half the time there is boxing already to cover wste and
water pipes running around the room anyway. I find that tiled boxing is
very useful as it forms a good place to put the coffee mug when having a
crap.

4/ fit a motorised valve, and hook up to the lighting/fan curcuit after the
isolator. And use a thermostat to control that. OR you could use a TRV I
suppose.Mounted off the boxing. On reflection TRV is good, because it acts
as a flow limiter as it appraoches cutoff, which will mean that the temp
variation underfloor will ne less violent

5/. Tap into the CH circuit using a pair of ball valves so you can isolate
and/or balance the thing in case it hogs the flow.

6/. screwdown 17mm chipboard (water resistant)

7/. Run the system up for a week or two to check for warping and shrinkage
in the chip.

8./. Then tile using about 10mm bed of Ardurit flexible as recommended
elsewhere, and if the joists are not too bouncy, it wont' crack.

Now the only thing exposed to potential high temperatures is the chip (you
CAN use ply, but believe me an underfloor heated chip floor stays DRY. Mine
is not heated and is tiled chip, and the only problems I got were using non
flexible thin bed, and a leaking toilet that swelled it and cracked tte
tiles off. New tiles, cement as described, fixed leak and its AOK)

Use a good flexible tile adhesive such as Ardex Ardu-Flex 7001 Timber
System.

Iit will be complicated of your joist are herring boned, or if the UF void
is fill of pipes and wires ...but thats why you call yourself a D-I-Yer.

You may want to add a heated towel rail ino the overall loop too.

This sounds a very practical arrangement especially the suggestion of
tapping into the return flow---although on my system of 12 radiators the
return flow is quite cool-but-is this just because I am comparing it to the
60 degree output pipe.

The floor is about 15 metres from the boiler and is 10 square metres
roughly2.5x2.5 with wet shower bidet wash basin and wc.Standard suspended
floor over concrete solum in my bungalow.
Controls/valve and pipe connections/supply are not a problem they can be
housed underfloor in the bedroom next door.
Joists are the usuall 600 centres so plastic should loop round no
problem.Could use small bore copper tho-or even 15mm it would easily bend in
situ using a d-i-y home made chip board pipe bender.
I like the TRV motorised valves burn out!!.

Is chip board better for this application since it is uniform as compared to
plywood which could expand at different rates over 10 square metres.


If you are only doing an ensuite, then just arrange for e.g. a longish
arrangement of a loop of copper pipe under the floor, and stick a
motorised
valve and a thermostat on it. In fact the plastic MAY be OK as well.

You can go a bit higher temp wise if you are not in screed, and the pipe
is
not too close to the woodwork.

Especially if you tap into the return side of the CH circuit where temps
will be a little lower.


The thing about the temp reduction stuff is that its necessary for
screeded
floors to prevent cracking. I think my water goes underfloor at 45C or
thereabouts.

If I were doing this on an unpstairs room. I'd do the following.

1/.remove floorboards

2/. lay about 2" of celotex, or white EP foam if you are cheapskating,
between the joists on the downstairs ceilings

3/. Lay a loop of pipe - probably copper to be able to do the tight bends
down alomgside each joist and nack up alongside the adjacent one in the
same gap. Keep spacings about 2" from the joists if possible, and use more
white foam/celotex to insulate joists from the pipework.

4/. Since I am the sort of person I am, rather than notch every joist to
make the pipework connect, I'd bring it all up and run along a skirting,
and box in later. Half the time there is boxing already to cover wste and
water pipes running around the room anyway. I find that tiled boxing is
very useful as it forms a good place to put the coffee mug when having a
crap.

4/ fit a motorised valve, and hook up to the lighting/fan curcuit after
the
isolator. And use a thermostat to control that. OR you could use a TRV I
suppose.Mounted off the boxing. On reflection TRV is good, because it acts
as a flow limiter as it appraoches cutoff, which will mean that the temp
variation underfloor will ne less violent

5/. Tap into the CH circuit using a pair of ball valves so you can isolate
and/or balance the thing in case it hogs the flow.

6/. screwdown 17mm chipboard (water resistant)

7/. Run the system up for a week or two to check for warping and shrinkage
in the chip.

8./. Then tile using about 10mm bed of Ardurit flexible as recommended
elsewhere, and if the joists are not too bouncy, it wont' crack.

Now the only thing exposed to potential high temperatures is the chip (you
CAN use ply, but believe me an underfloor heated chip floor stays DRY.
Mine
is not heated and is tiled chip, and the only problems I got were using
non
flexible thin bed, and a leaking toilet that swelled it and cracked tte
tiles off. New tiles, cement as described, fixed leak and its AOK)

Use a good flexible tile adhesive such as Ardex Ardu-Flex 7001 Timber
System.

Iit will be complicated of your joist are herring boned, or if the UF void
is fill of pipes and wires ...but thats why you call yourself a D-I-Yer.

You may want to add a heated towel rail ino the overall loop too.

On Thu, 29 Dec 2005 12:40:41 GMT, tom patton wrote:

This sounds a very practical arrangement especially the suggestion of
tapping into the return flow---although on my system of 12 radiators the
return flow is quite cool-but-is this just because I am comparing it to the
60 degree output pipe.

The floor is about 15 metres from the boiler and is 10 square metres
roughly2.5x2.5 with wet shower bidet wash basin and wc.Standard suspended
floor over concrete solum in my bungalow.
Controls/valve and pipe connections/supply are not a problem they can be
housed underfloor in the bedroom next door.
Joists are the usuall 600 centres so plastic should loop round no
problem.Could use small bore copper tho-or even 15mm it would easily bend in
situ using a d-i-y home made chip board pipe bender.
I like the TRV motorised valves burn out!!.

Is chip board better for this application since it is uniform as compared to
plywood which could expand at different rates over 10 square metres.


It certainly will expand like buggery if it dOES get wet..and tirn into
powder...ply si definitely better but on;y you can estabish if its
necessary to spend that much on it.

If you have kids who splash everywhere and so on and never clear it up,
then its possible that tiles even with waterporoof grout may not hold the
water out.

However, even marine ply, when soaked, degrades...

You COULD if you have a concrete sub floor lay down insiulation and DPM and
lay plastic pipes in the screed for the bathroom. Not understanding exactly
what you have, I'll leave that to your judgement -which seems to have
cottoned on to what I was trying to say pretty well, so I trust it :-)


If you are only doing an ensuite, then just arrange for e.g. a longish
arrangement of a loop of copper pipe under the floor, and stick a
motorised
valve and a thermostat on it. In fact the plastic MAY be OK as well.

You can go a bit higher temp wise if you are not in screed, and the pipe
is
not too close to the woodwork.

Especially if you tap into the return side of the CH circuit where temps
will be a little lower.


The thing about the temp reduction stuff is that its necessary for
screeded
floors to prevent cracking. I think my water goes underfloor at 45C or
thereabouts.

If I were doing this on an unpstairs room. I'd do the following.

1/.remove floorboards

2/. lay about 2" of celotex, or white EP foam if you are cheapskating,
between the joists on the downstairs ceilings

3/. Lay a loop of pipe - probably copper to be able to do the tight bends
down alomgside each joist and nack up alongside the adjacent one in the
same gap. Keep spacings about 2" from the joists if possible, and use more
white foam/celotex to insulate joists from the pipework.

4/. Since I am the sort of person I am, rather than notch every joist to
make the pipework connect, I'd bring it all up and run along a skirting,
and box in later. Half the time there is boxing already to cover wste and
water pipes running around the room anyway. I find that tiled boxing is
very useful as it forms a good place to put the coffee mug when having a
crap.

4/ fit a motorised valve, and hook up to the lighting/fan curcuit after
the
isolator. And use a thermostat to control that. OR you could use a TRV I
suppose.Mounted off the boxing. On reflection TRV is good, because it acts
as a flow limiter as it appraoches cutoff, which will mean that the temp
variation underfloor will ne less violent

5/. Tap into the CH circuit using a pair of ball valves so you can isolate
and/or balance the thing in case it hogs the flow.

6/. screwdown 17mm chipboard (water resistant)

7/. Run the system up for a week or two to check for warping and shrinkage
in the chip.

8./. Then tile using about 10mm bed of Ardurit flexible as recommended
elsewhere, and if the joists are not too bouncy, it wont' crack.

Now the only thing exposed to potential high temperatures is the chip (you
CAN use ply, but believe me an underfloor heated chip floor stays DRY.
Mine
is not heated and is tiled chip, and the only problems I got were using
non
flexible thin bed, and a leaking toilet that swelled it and cracked tte
tiles off. New tiles, cement as described, fixed leak and its AOK)

Use a good flexible tile adhesive such as Ardex Ardu-Flex 7001 Timber
System.

Iit will be complicated of your joist are herring boned, or if the UF void
is fill of pipes and wires ...but thats why you call yourself a D-I-Yer.

You may want to add a heated towel rail ino the overall loop too.

Is chip board better for this application since it is uniform as
compared to
plywood which could expand at different rates over 10 square metres.

I was thinking of using exterior grade ply 18mm only £15 a sheet 3 should
do.

Our children have left home so shower will get used by two adults who do
not spend 30 minutes in it unlike my 28 year old son.
I was thinking of using the Ardex system of flexible cement and grout after
priming with their product.
Of course the ultimate finish would be glassfibre with a gel coat-so easy to
put down-and 100% waterproof --------but-my wife wants her Italian
tiles---------

It certainly will expand like buggery if it dOES get wet..and tirn into
powder...ply si definitely better but on;y you can estabish if its
necessary to spend that much on it.
If you have kids who splash everywhere and so on and never clear it up,
then its possible that tiles even with waterporoof grout may not hold the
water out.

However, even marine ply, when soaked, degrades...

The ensuite is part of an extension to my bedroom area on my bungalow. I
have just pushed the bedroom back wall out 2 metres to extend my existing
bedroom and the ensuite is behind the bedroom next to ours-so the ensuite
has two outside walls facing south.

Could build up the solum with hard core and put down concrete about 2 cubes
of hard core but it would mean barrowing it in over new floors.
I just dont like the idea of concreting the soil pipe and all the
connections to the other 3 units-shower wash basin bidet.Then theres the
problem of getting the water to all 3 plus the WC of course they could all
go in ducts in the hard core/screed-----under the suspended floor is much
easier.

You COULD if you have a concrete sub floor lay down insiulation and DPM
and
lay plastic pipes in the screed for the bathroom. Not understanding
exactly
what you have, I'll leave that to your judgement -which seems to have
cottoned on to what I was trying to say pretty well, so I trust it :-)


If you are only doing an ensuite, then just arrange for e.g. a longish
arrangement of a loop of copper pipe under the floor, and stick a
motorised
valve and a thermostat on it. In fact the plastic MAY be OK as well.

You can go a bit higher temp wise if you are not in screed, and the
pipe
is
not too close to the woodwork.

Especially if you tap into the return side of the CH circuit where
temps
will be a little lower.


The thing about the temp reduction stuff is that its necessary for
screeded
floors to prevent cracking. I think my water goes underfloor at 45C or
thereabouts.

If I were doing this on an unpstairs room. I'd do the following.

1/.remove floorboards

2/. lay about 2" of celotex, or white EP foam if you are cheapskating,
between the joists on the downstairs ceilings

3/. Lay a loop of pipe - probably copper to be able to do the tight
bends
down alomgside each joist and nack up alongside the adjacent one in the
same gap. Keep spacings about 2" from the joists if possible, and use
more
white foam/celotex to insulate joists from the pipework.

4/. Since I am the sort of person I am, rather than notch every joist
to
make the pipework connect, I'd bring it all up and run along a
skirting,
and box in later. Half the time there is boxing already to cover wste
and
water pipes running around the room anyway. I find that tiled boxing is
very useful as it forms a good place to put the coffee mug when having
a
crap.

4/ fit a motorised valve, and hook up to the lighting/fan curcuit after
the
isolator. And use a thermostat to control that. OR you could use a TRV
I
suppose.Mounted off the boxing. On reflection TRV is good, because it
acts
as a flow limiter as it appraoches cutoff, which will mean that the
temp
variation underfloor will ne less violent

5/. Tap into the CH circuit using a pair of ball valves so you can
isolate
and/or balance the thing in case it hogs the flow.

6/. screwdown 17mm chipboard (water resistant)

7/. Run the system up for a week or two to check for warping and
shrinkage
in the chip.

8./. Then tile using about 10mm bed of Ardurit flexible as recommended
elsewhere, and if the joists are not too bouncy, it wont' crack.

Now the only thing exposed to potential high temperatures is the chip
(you
CAN use ply, but believe me an underfloor heated chip floor stays DRY.
Mine
is not heated and is tiled chip, and the only problems I got were using
non
flexible thin bed, and a leaking toilet that swelled it and cracked tte
tiles off. New tiles, cement as described, fixed leak and its AOK)

Use a good flexible tile adhesive such as Ardex Ardu-Flex 7001 Timber
System.

Iit will be complicated of your joist are herring boned, or if the UF
void
is fill of pipes and wires ...but thats why you call yourself a
D-I-Yer.

You may want to add a heated towel rail ino the overall loop too.