Hi all,

I've just had a new loft conversion done (well, it took about 12 months
what with the loft company taking forever to finish and the decorators
mucking around and eventually running off - fortunately with me owing
them money rather than the other way around).

Due to some bad advice and planning early on, there is no central heating
in the conversion (which is a bedroom with balcony ie lots of Velux, plus
a bathroom). The bathroom is all tiled, with electric underfloor heating
and an electric towel rail. The underfloor is nice as it keeps the tiles
from freezing the skin off the soles of your feet in winter, but the towel
rail is awful - takes ages to warm up and uses masses of electricity
without really heating the bathroom. Also the bedroom is very cold - the
old insulation in the original ceiling seems to be stopping any heat from
the rest of the house from making its way upstairs.

Ideally I'd like to extend the central heating upstairs, so I'd appreciate
any comments from those in the know. First here's a summary of the CH/HW
system:

Boiler is an old Potterton Netaheat 10-16 Mk II F, conventional gas-fired
boiler, pumped, with a 3-port motorised valve. There is a cold water tank
in the eaves space, a hot water cylinder in the airing closet on the 1st
floor next to the pump/3-port valve, and the header tank for the CH is in
the apex of the roof not next to the cold water tank. The CH is a
micro-bore system (with feed and return at opposite ends of the
radiators). I have no idea where the manifolds are located.

Based on the airing closet and loft location, the following scheme is
possible in terms of running pipes - I'd like to know if it's feasible
though:

- tap into the CH feed just after the 3-port valve
- take the pipe straight up about 2m to the ceiling of the 1st floor then
under the loft floor into the south eaves (about 3m), across the outside
of the loft room wall (another 3m) then enter the loft room
- install a long low radiator or two into the loft room along the 5m wall,
with return to the eaves space
- across the eaves again (8m) and into the bathroom, with a single
radiator
- back into the eaves (5m) under the floor (3m) and down to the original
junction (2m) for a total of about 30m extra pipework
- presumably a pressure relief valve would also be needed between the new
outbound and return pipes

Does this sound feasible? Effectively it creates a combination of single
pipe loop and micro-bore piping, but other than locating and hooking into
the split of the hot feed into the manifolds & the corresponding return is
there anything else I can do? As the loft will get the freshest hot water,
will the returning water still be warm enough to heat the rest of the rads
(there are 12 existing radiators at the moment)? The eaves spaces are
uninsulated (well the floor and walls of the eaves are but the roof is
just the back of the tiles) - would the CH piping need to be insulated to
retain the heat or is that overkill?

Alternatively I could install a new 2-port valve on the Ch side of the
3-port valve, to split the CH system into two separate circuits - one for
the existing house and another just for the loft. This way the loft
circuit would just have the loft radiators on it, and a separate
thermostat could be used so that the two zones are independently
regulated. This would require a more complicated control system than the
current mechanical/thermostatic one though.

Does the pipework have to be copper, or can parts be plastic? Owing to the
spaces that need to be worked in, parts might be really difficult to work
in copper.

Is the existing pump likely to need to be replaced to handle the work of
pumping hot water up 2.3m above what it does currently? Or is it ok since
the header tank is right at the top of the house ie way above the proposed
new loft radiators?

I haven't done any formal calculations on the boiler rating to see if it
has sufficient output to heat the new space but gut feel says its ok as it
can heat the original parts of the house pretty fast from cold; also the
new loft is well insulated so should retain its heat well if I can just
get it in there in the first place!

I've read about using long low radiators which resemble standard skirting
boards but are metal and contain two pipes for feed and return, which I
could run along 5-10m of the room instead of using conventional radiators.
Any thoughts?

Thanks,
Zane.

On Tue, 6 Jan 2004 00:00:50 +0000 (UTC), wrote:


Hi all,

I've just had a new loft conversion done (well, it took about 12 months
what with the loft company taking forever to finish and the decorators
mucking around and eventually running off - fortunately with me owing
them money rather than the other way around).

Due to some bad advice and planning early on, there is no central heating
in the conversion (which is a bedroom with balcony ie lots of Velux, plus
a bathroom). The bathroom is all tiled, with electric underfloor heating
and an electric towel rail. The underfloor is nice as it keeps the tiles
from freezing the skin off the soles of your feet in winter, but the towel
rail is awful - takes ages to warm up and uses masses of electricity
without really heating the bathroom. Also the bedroom is very cold - the
old insulation in the original ceiling seems to be stopping any heat from
the rest of the house from making its way upstairs.

Ideally I'd like to extend the central heating upstairs, so I'd appreciate
any comments from those in the know. First here's a summary of the CH/HW
system:

Boiler is an old Potterton Netaheat 10-16 Mk II F, conventional gas-fired
boiler, pumped, with a 3-port motorised valve. There is a cold water tank
in the eaves space, a hot water cylinder in the airing closet on the 1st
floor next to the pump/3-port valve, and the header tank for the CH is in
the apex of the roof not next to the cold water tank. The CH is a
micro-bore system (with feed and return at opposite ends of the
radiators). I have no idea where the manifolds are located.

Based on the airing closet and loft location, the following scheme is
possible in terms of running pipes - I'd like to know if it's feasible
though:

- tap into the CH feed just after the 3-port valve
- take the pipe straight up about 2m to the ceiling of the 1st floor then
under the loft floor into the south eaves (about 3m), across the outside
of the loft room wall (another 3m) then enter the loft room
- install a long low radiator or two into the loft room along the 5m wall,
with return to the eaves space
- across the eaves again (8m) and into the bathroom, with a single
radiator
- back into the eaves (5m) under the floor (3m) and down to the original
junction (2m) for a total of about 30m extra pipework
- presumably a pressure relief valve would also be needed between the new
outbound and return pipes

Does this sound feasible? Effectively it creates a combination of single
pipe loop and micro-bore piping, but other than locating and hooking into
the split of the hot feed into the manifolds & the corresponding return is
there anything else I can do?

It's a bad idea to try to combine a one pipe and a two pipe system and
to be honest a one pipe system is not great to begin with.

Really, you should plan to add the new pieces in two pipe. This
doesn't need to be done in microbore or into a manfold. You need to
tap into the main (probably 22mm) run after the 3 port valve as you
say but then find the return.

Since the pipe runs are quite long, it is important to size the pipes
adequately - don't guess because you will be disappointed if you make
them too small.

There is a note on how to do this at

http://www.cda.org.uk/megab2/build/Pub150%20UKCB.pdf

You need to size the radiators to meet the heat loss and then the flow
rate required and pipe size are determined from this. Again, do do
the proper heat loss calculations using one of the radiator company's
programs - don't guess or you may have another disappointment like the
towel rail.


As the loft will get the freshest hot water,
will the returning water still be warm enough to heat the rest of the rads
(there are 12 existing radiators at the moment)?

The number of radiators is irrelevant. What matters is their heat
output. You can get these figures by measuring them and referring to
manufacturer data sheets. On a conventional boiler such as you
have, the actual outputs will be 89% of the numbers in the table
because the temperature is lower than that used for testing them.


The eaves spaces are
uninsulated (well the floor and walls of the eaves are but the roof is
just the back of the tiles) - would the CH piping need to be insulated to
retain the heat or is that overkill?

Ideally the pipes should be run on the inside of the insulation.
However, if you have to run them outside the insulation, then they
must be insulated with pipe insulation of at least the pipe diameter
thick - i.e. the total insulated size of a 22mm pipe becomes 66mm.



Alternatively I could install a new 2-port valve on the Ch side of the
3-port valve, to split the CH system into two separate circuits - one for
the existing house and another just for the loft.

You could do that, but it might need more work on the rest of the
system to convert it to use entirely two port valves. If you look on
Honeywell's web site it is called an S-plan plus system then. You
could just zone it off with a two port valve, but then the loft
heating is at the mercy of the rest of the house if you see what I
mean.

This way the loft
circuit would just have the loft radiators on it, and a separate
thermostat could be used so that the two zones are independently
regulated. This would require a more complicated control system than the
current mechanical/thermostatic one though.

yes.


Does the pipework have to be copper, or can parts be plastic? Owing to the
spaces that need to be worked in, parts might be really difficult to work
in copper.

It can be in plastic if you like.



Is the existing pump likely to need to be replaced to handle the work of
pumping hot water up 2.3m above what it does currently?

Hard to say. The issue is delivering the volume of water at the
rate required - both will increase as a result of this addition.

Or is it ok since
the header tank is right at the top of the house ie way above the proposed
new loft radiators?

As long as you have about a metre of head of the tank above the top
radiator circulation should be OK. The issue is as above.




I haven't done any formal calculations on the boiler rating to see if it
has sufficient output to heat the new space but gut feel says its ok as it
can heat the original parts of the house pretty fast from cold; also the
new loft is well insulated so should retain its heat well if I can just
get it in there in the first place!

Don't work on gut feel. This is not a large boiler so again you may
be disappointed. On the other hand, it is probably due for
replacement and you could simply try it out and replace the boiler if
it proves to be inadequate.



I've read about using long low radiators which resemble standard skirting
boards but are metal and contain two pipes for feed and return, which I
could run along 5-10m of the room instead of using conventional radiators.
Any thoughts?

Myson make them among others. I've used them in a similar situation
to yours. I've also used long conventional radiators 300mm high.

You have to see whether you get enough heat output for your
requirements.





Thanks,
Zane.

..andy

To email, substitute .nospam with .gl

wrote in message ...

Hi all,

I've just had a new loft conversion done ....

....the bedroom is very cold - the
old insulation in the original ceiling seems to be stopping any heat from
the rest of the house from making its way upstairs.

snip

The old insulation should have been removed. This would make the loft bedroom
much warmer, probably enough to need only very minimal heating, if any. Is it
impossible to remove it now? This seems like a lot less work than all the
heating extensions you are planning.

Peter

In article ,
Peter Taylor wrote:
I've just had a new loft conversion done ....

....the bedroom is very cold - the
old insulation in the original ceiling seems to be stopping any heat from
the rest of the house from making its way upstairs.

The old insulation should have been removed. This would make the loft bedroom
much warmer, probably enough to need only very minimal heating, if any. Is it
impossible to remove it now? This seems like a lot less work than all the
heating extensions you are planning.

It would be tricky as it is no longer possible to lift the floorboards.
However with a bit of stiff wire and some patience it may be possible to
fish it out from the eaves.

However this would increase the heat loss of the 1st floor bedrooms, as
the heat would be able to escape into the loft. Once the insulation is out
it will be very difficult to impossible to put back. You can sort of see
how it's been done he http://www.wilson.st/100_0246.jpg

I like the idea of improving the heating without installing CH but I'd
hate to make the 1st floor cold as a side-effect. Any ideas as to whether
this would be a problem?

Thanks,
Zane.

In article ,
Andy Hall wrote:

Thanks for the quick & detailed reply.

On Tue, 6 Jan 2004 00:00:50 +0000 (UTC), wrote:
Does this sound feasible? Effectively it creates a combination of single
pipe loop and micro-bore piping, but other than locating and hooking into
the split of the hot feed into the manifolds & the corresponding return is
there anything else I can do?

It's a bad idea to try to combine a one pipe and a two pipe system and
to be honest a one pipe system is not great to begin with.

Fair enough. However if the CH is split in two (as described below) surely
a single pipe system of just two radiators is not such a bad thing? It's
not long enough to end up with the last radiator being too cool.

Really, you should plan to add the new pieces in two pipe. This
doesn't need to be done in microbore or into a manfold. You need to
tap into the main (probably 22mm) run after the 3 port valve as you
say but then find the return.

How would I go about finding the return? There is no access to any of the
pipework except in the airing closet where the hot comes in. Presumably
where the coil exits the hot water cylinder is a return - would that join
the CH return and would it therefore do to connect the loft radiator
return to the hot water return?

Would it work to tap into the main with a simple T (and same again at the
return)? Ie would enough water flow up 2.5m in this situation, or would it
require a motorised valve to shut off the "easy" route of the existing CH
piping?

Since the pipe runs are quite long, it is important to size the pipes
adequately - don't guess because you will be disappointed if you make
them too small.

There is a note on how to do this at

http://www.cda.org.uk/megab2/build/Pub150%20UKCB.pdf

Excellent. Looks a bit complicated but following step-by-step will
probably do it.

You need to size the radiators to meet the heat loss and then the flow
rate required and pipe size are determined from this. Again, do do
the proper heat loss calculations using one of the radiator company's
programs - don't guess or you may have another disappointment like the
towel rail.

Agreed.

Alternatively I could install a new 2-port valve on the Ch side of the
3-port valve, to split the CH system into two separate circuits - one for
the existing house and another just for the loft.

You could do that, but it might need more work on the rest of the
system to convert it to use entirely two port valves. If you look on
Honeywell's web site it is called an S-plan plus system then. You
could just zone it off with a two port valve, but then the loft
heating is at the mercy of the rest of the house if you see what I
mean.

What about a second 3-port valve installed on the CH side of the existing
3-port valve? This could split the CH water into two circuits. If
controlled by a thermostat in the loft, then this could switch the CH hot
water between the circuits, favouring the loft first. This could then be
independent of the rest of the system. The loft would heat before the
downstairs but once warm enough the downstairs would heat up. As long as
the loft thermostat had a range (eg heat to 20 degrees, but don't
reactivate until temp drops to 16 degrees) there wouldn't be excessive
switching between the two.

Don't work on gut feel. This is not a large boiler so again you may
be disappointed. On the other hand, it is probably due for
replacement and you could simply try it out and replace the boiler if
it proves to be inadequate.

I'm hoping not to have to do this for a while, but might be forced into
it.

Thanks,
Zane.

wrote in message
...
In article ,
Peter Taylor wrote:
I've just had a new loft conversion done ....

....the bedroom is very cold - the
old insulation in the original ceiling seems to be stopping any heat
from
the rest of the house from making its way upstairs.

The old insulation should have been removed. This would make the loft
bedroom
much warmer, probably enough to need only very minimal heating, if any.
Is it
impossible to remove it now? This seems like a lot less work than all
the
heating extensions you are planning.

It would be tricky as it is no longer possible to lift the floorboards.
However with a bit of stiff wire and some patience it may be possible to
fish it out from the eaves.

Even if there were no insulation there in the first place, the requirements
for 30 minute fire protection between the old house and the new loft
conversion would require new mineral fibre insulation beneath the floor of
the loft conversion, nailed to the joists. To remove it would be highly
irresponsible. The new room requires its own heating. To extend the CH will
almost certainly require repositioning the header tank. The common approach
is to fit an electric wall heater with integral timer and thermostat. The
loft room should be well insulated and will heat up quickly.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

Bob Mannix wrote

Even if there were no insulation there in the first place, the requirements
for 30 minute fire protection between the old house and the new loft
conversion would require new mineral fibre insulation beneath the floor of
the loft conversion, nailed to the joists. To remove it would be highly
irresponsible.

You are right about the ceiling needing to be 30 minute FR, but this is achieved
by the plasterboard and skim (or by lath & plaster in older property). Thermal
insulation material laid above the ceiling adds nothing to the ceiling's fire
resistance. As I said, the original insulation to the area of the new loft
floor should have been removed - this is not needed as there will be new
insulation on/between the rafters. The original insulation in the eaves should
remain unless the new rafter insulation is carried on down the slope to joist
level.

Peter

Presumably where the coil exits the hot water cylinder is a return -
would that join the CH return and would it therefore do to connect
the loft radiator return to the hot water return?

Yes. Perfect for it, provided it is run in 22mm.

Would it work to tap into the main with a simple T (and same again at
the return)? Ie would enough water flow up 2.5m in this situation, or
would it require a motorised valve to shut off the "easy" route of
the existing CH piping?

Making the water flow down all the lines when the zone valves are all open
is called balancing. You will need to balance the entire system after it is
all plumbed in.

What about a second 3-port valve installed on the CH side of the
existing 3-port valve? This could split the CH water into two
circuits. If controlled by a thermostat in the loft, then this could
switch the CH hot water between the circuits, favouring the loft
first.

Why do you want to favour the loft? A properly balanced system will get all
the radiators in the house hot fast. To subzone, I'd recommend replacing the
3 port valve with multiple 2 port valves.

If you must keep the 3 port valve (i.e. it is a diverter and you like HWC
priority), subzone just the heating circuit with an extra two 2 port valves.
Wiring then gets slightly more complicated as it is non-standard.

Christian.

The old insulation should have been removed. This would make the
loft bedroom much warmer, probably enough to need only very minimal
heating, if any. Is it impossible to remove it now? This seems like
a lot less work than all the heating extensions you are planning.

I disagree. If the OP intends to have subzoned heating, then insulation
between zones is actually quite useful, as heat required for occupied rooms
doesn't leak into unoccupied zones.

Christian.

"Peter Taylor" wrote in message
...
Bob Mannix wrote

Even if there were no insulation there in the first place, the
requirements
for 30 minute fire protection between the old house and the new loft
conversion would require new mineral fibre insulation beneath the floor
of
the loft conversion, nailed to the joists. To remove it would be highly
irresponsible.

You are right about the ceiling needing to be 30 minute FR, but this is
achieved
by the plasterboard and skim (or by lath & plaster in older property).
Thermal
insulation material laid above the ceiling adds nothing to the ceiling's
fire
resistance. As I said, the original insulation to the area of the new
loft
floor should have been removed - this is not needed as there will be new
insulation on/between the rafters. The original insulation in the eaves
should
remain unless the new rafter insulation is carried on down the slope to
joist
level.


I don't believe you are correct. A single sheet of skimmed plasterboard is
insufficient to provide the fire protection (unless it is Fireline
plasterboard). The requirement for mineral fibre insulation was part of the
fire protection requirements for my loft conversion and its protection was
added to that provided by the ceiling to make up the required 30 minutes. A
depth of 65mm of mineral fibre insulation, nailed to the joists either side
was required (glass fibre is not allowed as it melts). The floor was not
allowed to be laid until the BCO had inspected the installation of the
mineral fibre.

Two sheets of plasterboard with a 12mm (AFAICR) gap would also do, but
that's a lot more difficult.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

In article ,
Bob Mannix wrote:
....the bedroom is very cold - the
old insulation in the original ceiling seems to be stopping any heat
from
the rest of the house from making its way upstairs.

The old insulation should have been removed. This would make the loft
bedroom
much warmer, probably enough to need only very minimal heating, if any.
Is it
impossible to remove it now? This seems like a lot less work than all
the
heating extensions you are planning.

It would be tricky as it is no longer possible to lift the floorboards.
However with a bit of stiff wire and some patience it may be possible to
fish it out from the eaves.

Even if there were no insulation there in the first place, the requirements
for 30 minute fire protection between the old house and the new loft
conversion would require new mineral fibre insulation beneath the floor of
the loft conversion, nailed to the joists. To remove it would be highly
irresponsible.

Interesting. The plans state various FR requirements including the
floor-boards, insulation, doors etc. They were approved and the BCO made
several visits including before the floor-boards went down. The insulation
between the 1st floor ceiling and the 2nd floor boards in the original
50mm insulation that went in years ago - no special mineral fibre.

The new room requires its own heating. To extend the CH will
almost certainly require repositioning the header tank. The common approach

To where? It's already in the apex of the roof, ie in the ceiling of the
2nd floor. As it's there already I am thinking of piping in new CH as I
believe in the long run ...

is to fit an electric wall heater with integral timer and thermostat. The
loft room should be well insulated and will heat up quickly.

.... it will be cheaper than electrics (especially if I can do it myself
for the cost of the materials + my time and a few crates of beers for my
more handy friend with all the tools). The loft bedroom is large (5m x 3m
+ 1.5m x 2m = 18m2) and so is the bathroom (5m x 1.8m).

One thing I was considering instead of CH is to install an air conditioner
with integral heat pump. Apparently the heat exchangers are very
efficient, and as the loft gets very hot in summer air-con will be a
nice-to-have anyway.

Zane.

On Tue, 6 Jan 2004 15:38:10 +0000 (UTC), wrote:

In article ,
Andy Hall wrote:

Thanks for the quick & detailed reply.

On Tue, 6 Jan 2004 00:00:50 +0000 (UTC), wrote:
Does this sound feasible? Effectively it creates a combination of single
pipe loop and micro-bore piping, but other than locating and hooking into
the split of the hot feed into the manifolds & the corresponding return is
there anything else I can do?

It's a bad idea to try to combine a one pipe and a two pipe system and
to be honest a one pipe system is not great to begin with.

Fair enough. However if the CH is split in two (as described below) surely
a single pipe system of just two radiators is not such a bad thing? It's
not long enough to end up with the last radiator being too cool.

The problem is that you are going to feed the entire house heating
circuit around this extra loop, and I suspect that you would have real
problems getting balancing to work between the different parts.


Really, you should plan to add the new pieces in two pipe. This
doesn't need to be done in microbore or into a manfold. You need to
tap into the main (probably 22mm) run after the 3 port valve as you
say but then find the return.

How would I go about finding the return? There is no access to any of the
pipework except in the airing closet where the hot comes in. Presumably
where the coil exits the hot water cylinder is a return - would that join
the CH return and would it therefore do to connect the loft radiator
return to the hot water return?

The exit from the cylinder coil will eventually join the return going
back to the boiler. However, it is not a good idea to connect your
additional radiators to that point. You should really connect to the
return from the heating immediately before where the cylinder coil
return joins it. There's a fairly good chance that it will be close
to the cylinder and probably under the airing cupboard floor. If
you are going to use zone valves then connecting to the return near
the cylinder should be OK.



Would it work to tap into the main with a simple T (and same again at the
return)? Ie would enough water flow up 2.5m in this situation, or would it
require a motorised valve to shut off the "easy" route of the existing CH
piping?

This is why you need to do the pipe resistance calculations.
You need to make sure that the new pipework has enough water carrying
capacity to cover the needs of the new radiators.

The flow between radiators on the new part and those on the old part
need to be balanced. This will mean that you will have to balance
radiators on the old part of the system against the new.
It may also be necessary to increase the pump setting. In
principle, there is no reason why a pump can't cover a three floor
building - it really depends on the flow conditions in the system.




Since the pipe runs are quite long, it is important to size the pipes
adequately - don't guess because you will be disappointed if you make
them too small.

There is a note on how to do this at

http://www.cda.org.uk/megab2/build/Pub150%20UKCB.pdf

Excellent. Looks a bit complicated but following step-by-step will
probably do it.

It's actually not that bad. At a guess, I suspect that you will end
up wanting to use 22mm for most of the distance to the radiators and
15mm for immediate connections, but it does depend on the heat
requirements. You might be able to get away with 15mm throughout.



You need to size the radiators to meet the heat loss and then the flow
rate required and pipe size are determined from this. Again, do do
the proper heat loss calculations using one of the radiator company's
programs - don't guess or you may have another disappointment like the
towel rail.

Agreed.

Alternatively I could install a new 2-port valve on the Ch side of the
3-port valve, to split the CH system into two separate circuits - one for
the existing house and another just for the loft.

You could do that, but it might need more work on the rest of the
system to convert it to use entirely two port valves. If you look on
Honeywell's web site it is called an S-plan plus system then. You
could just zone it off with a two port valve, but then the loft
heating is at the mercy of the rest of the house if you see what I
mean.

What about a second 3-port valve installed on the CH side of the existing
3-port valve? This could split the CH water into two circuits. If
controlled by a thermostat in the loft, then this could switch the CH hot
water between the circuits, favouring the loft first. This could then be
independent of the rest of the system. The loft would heat before the
downstairs but once warm enough the downstairs would heat up. As long as
the loft thermostat had a range (eg heat to 20 degrees, but don't
reactivate until temp drops to 16 degrees) there wouldn't be excessive
switching between the two.

You could do that, but it might cause some funny temperature effects
around the house. If you use an electronic type of thermostat you
could play around with setback temperatures and with hysteresis (i.e.
the difference between the on and off temperatures).




Don't work on gut feel. This is not a large boiler so again you may
be disappointed. On the other hand, it is probably due for
replacement and you could simply try it out and replace the boiler if
it proves to be inadequate.

I'm hoping not to have to do this for a while, but might be forced into
it.


You can check that pretty easily by measuring and sizing the existing
radiators.




Thanks,
Zane.

..andy

To email, substitute .nospam with .gl

The current requirement is for sound insulation to a loft conversion floor
means mineral wool is required, and as the floor needs to be 30min FR, the
wool will often need to be laid on chicken wire drapped over the joists. The
boarding & wool has to be taken eaves to eaves (ie the void areas also need
it).

RT




wrote in message
...
In article ,
Bob Mannix wrote:
....the bedroom is very cold - the
old insulation in the original ceiling seems to be stopping any heat
from
the rest of the house from making its way upstairs.

The old insulation should have been removed. This would make the loft
bedroom
much warmer, probably enough to need only very minimal heating, if
any.
Is it
impossible to remove it now? This seems like a lot less work than all
the
heating extensions you are planning.

It would be tricky as it is no longer possible to lift the floorboards.
However with a bit of stiff wire and some patience it may be possible
to
fish it out from the eaves.

Even if there were no insulation there in the first place, the
requirements
for 30 minute fire protection between the old house and the new loft
conversion would require new mineral fibre insulation beneath the floor
of
the loft conversion, nailed to the joists. To remove it would be highly
irresponsible.

Interesting. The plans state various FR requirements including the
floor-boards, insulation, doors etc. They were approved and the BCO made
several visits including before the floor-boards went down. The insulation
between the 1st floor ceiling and the 2nd floor boards in the original
50mm insulation that went in years ago - no special mineral fibre.

The new room requires its own heating. To extend the CH will
almost certainly require repositioning the header tank. The common
approach

To where? It's already in the apex of the roof, ie in the ceiling of the
2nd floor. As it's there already I am thinking of piping in new CH as I
believe in the long run ...

is to fit an electric wall heater with integral timer and thermostat. The
loft room should be well insulated and will heat up quickly.

... it will be cheaper than electrics (especially if I can do it myself
for the cost of the materials + my time and a few crates of beers for my
more handy friend with all the tools). The loft bedroom is large (5m x 3m
+ 1.5m x 2m = 18m2) and so is the bathroom (5m x 1.8m).

One thing I was considering instead of CH is to install an air conditioner
with integral heat pump. Apparently the heat exchangers are very
efficient, and as the loft gets very hot in summer air-con will be a
nice-to-have anyway.

Zane.

In article , wrote:
How would I go about finding the return? There is no access to
any of the pipework except in the airing closet where the hot
comes in. Presumably where the coil exits the hot water cylinder
is a return - would that join the CH return and would it
therefore do to connect the loft radiator return to the hot
water return?

If you do you might just have problems with radiators getting warm when they
shouldn't: if returns from the heating connect into the system at two
different points (A and B in the diagram below), when the DHW is on the
pressure at these points will be different so you may get a reverse flow
through the radiators.


reverse circulation
------+-------------+---------- CH flow (off)- || --+
RAD RAD |
reverse^circulation V |
| | Pump |
+---A-------------B------------------Boiler --X----MV
| |
CYL |
| |
+----------------------------------O---HW flow ----+

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser http://www.sda.co.uk/qsedbuk.htm

wrote in message
...
In article ,
Bob Mannix wrote:
....the bedroom is very cold - the
old insulation in the original ceiling seems to be stopping any heat
from
the rest of the house from making its way upstairs.

The old insulation should have been removed. This would make the loft
bedroom
much warmer, probably enough to need only very minimal heating, if
any.
Is it
impossible to remove it now? This seems like a lot less work than all
the
heating extensions you are planning.

It would be tricky as it is no longer possible to lift the floorboards.
However with a bit of stiff wire and some patience it may be possible
to
fish it out from the eaves.

Even if there were no insulation there in the first place, the
requirements
for 30 minute fire protection between the old house and the new loft
conversion would require new mineral fibre insulation beneath the floor
of
the loft conversion, nailed to the joists. To remove it would be highly
irresponsible.

Interesting. The plans state various FR requirements including the
floor-boards, insulation, doors etc. They were approved and the BCO made
several visits including before the floor-boards went down. The insulation
between the 1st floor ceiling and the 2nd floor boards in the original
50mm insulation that went in years ago - no special mineral fibre.

Well I can only quote my own experience. "Mineral fibre" just means Rockwool
or similar, as long as it's not glass fibre - nothing special. It may be
that the plasterboard and floor boards together just about make it to 30
minutes and some authorities allow you to get away with that and some insist
on the extra given by the mineral fibre to give a safety margin. If it is
indeed old insulation and is not nailed to the joists and is even glass
fibre, then pulling it out will not be irresponsible, as it's doing nothing
(in terms of fire protection).


The new room requires its own heating. To extend the CH will
almost certainly require repositioning the header tank. The common
approach

To where? It's already in the apex of the roof, ie in the ceiling of the
2nd floor. As it's there already I am thinking of piping in new CH as I
believe in the long run ...

Sorry I may have missed the current tank position in an earlier thread.

is to fit an electric wall heater with integral timer and thermostat. The
loft room should be well insulated and will heat up quickly.

... it will be cheaper than electrics (especially if I can do it myself
for the cost of the materials + my time and a few crates of beers for my
more handy friend with all the tools). The loft bedroom is large (5m x 3m
+ 1.5m x 2m = 18m2) and so is the bathroom (5m x 1.8m).

Yes - for an area that size, you are probably right.

One thing I was considering instead of CH is to install an air conditioner
with integral heat pump. Apparently the heat exchangers are very
efficient, and as the loft gets very hot in summer air-con will be a
nice-to-have anyway.


Noisy though, and it's cheaper to open the windows!


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

On Tue, 06 Jan 2004 17:56:27 GMT, Tony Bryer
wrote:

In article , wrote:
How would I go about finding the return? There is no access to
any of the pipework except in the airing closet where the hot
comes in. Presumably where the coil exits the hot water cylinder
is a return - would that join the CH return and would it
therefore do to connect the loft radiator return to the hot
water return?

If you do you might just have problems with radiators getting warm when they
shouldn't: if returns from the heating connect into the system at two
different points (A and B in the diagram below), when the DHW is on the
pressure at these points will be different so you may get a reverse flow
through the radiators.


reverse circulation
------+-------------+---------- CH flow (off)- || --+
RAD RAD |
reverse^circulation V |
| | Pump |
+---A-------------B------------------Boiler --X----MV
| |
CYL |
| |
+----------------------------------O---HW flow ----+


It is better to connect to a common point, as you say. You can get
around the problem with appropriately placed zone valves and that may
be a more practical solution if the CH return pipe is not easily
accessible.



..andy

To email, substitute .nospam with .gl

Bob Mannix wrote

I don't believe you are correct. A single sheet of skimmed plasterboard is
insufficient to provide the fire protection (unless it is Fireline
plasterboard). The requirement for mineral fibre insulation was part of the
fire protection requirements for my loft conversion and its protection was
added to that provided by the ceiling to make up the required 30 minutes. A
depth of 65mm of mineral fibre insulation, nailed to the joists either side
was required (glass fibre is not allowed as it melts). The floor was not
allowed to be laid until the BCO had inspected the installation of the
mineral fibre.

Two sheets of plasterboard with a 12mm (AFAICR) gap would also do, but
that's a lot more difficult.

I don't know any details about your loft conversion Bob, so I pass no judgement
on whether you are right or wrong. I can say for certain that I have never come
across a BCO requiring thermal insulation when upgrading the fire resistance of
ceilings. Maybe there was an issue about sound insulation in your case?

I checked my copy of the British Gypsum White Book just to make sure my
understanding was correct. There are various different constructions considered
but the two important cases a

a minimum 15mm thick T & G flooring on 38mm timber joists at 450mm centres
with a ceiling of 9.5mm plasterboard with 5mm skim coat gives ½ hour (modified)
FR. The Building
Regs permit this relaxed construction over rooms but not over the escape route.

b ditto but with 12.5mm plasterboard and 5mm skim gives full ½ hour FR. This
is
what the Regs require over escape routes.

There is no requirement for thermal insulation in these details I am looking at.

I've also never heard of using 2 sheets of plasterboard with a 12mm gap. In the
above examples, 2 staggered layers of 12.5mm wallboard (without skim) will give
1 hour FR and 2 layers of 15mm Fireline unskimmed will give 1½ hours FR.

You can see the latest on-line version of the White Book on timber floors and
ceilings on http://www.british-gypsum.com/PDF/c60_103.pdf
Look at page 4 onwards

Peter

In article ,
Andy Hall wrote:

reverse circulation
------+-------------+---------- CH flow (off)- || --+
RAD RAD |
reverse^circulation V |
| | Pump |
+---A-------------B------------------Boiler --X----MV
| |
CYL |
| |
+----------------------------------O---HW flow ----+


It is better to connect to a common point, as you say. You can get
around the problem with appropriately placed zone valves and that may
be a more practical solution if the CH return pipe is not easily
accessible.

What about just installing one-way valves on both the cylinder return and
new CH return just before the two returns join? That will prevent the HW
return from supplying hot water into the new rads, won't it? Actually the
one-way valve on the cylinder side would not be necessary as it wouldn't
matter if hot water returning from the radiators made its way into the
cylinder coil, would it?

Zane.

On Wed, 7 Jan 2004 00:17:15 +0000 (UTC), wrote:

In article ,
Andy Hall wrote:

reverse circulation
------+-------------+---------- CH flow (off)- || --+
RAD RAD |
reverse^circulation V |
| | Pump |
+---A-------------B------------------Boiler --X----MV
| |
CYL |
| |
+----------------------------------O---HW flow ----+


It is better to connect to a common point, as you say. You can get
around the problem with appropriately placed zone valves and that may
be a more practical solution if the CH return pipe is not easily
accessible.

What about just installing one-way valves on both the cylinder return and
new CH return just before the two returns join? That will prevent the HW
return from supplying hot water into the new rads, won't it? Actually the
one-way valve on the cylinder side would not be necessary as it wouldn't
matter if hot water returning from the radiators made its way into the
cylinder coil, would it?

Zane.

It may work.

You don't want water flowing through the cylinder coil either when not
wanted, because it may transfer heat out of the cylinder.

There are three basic kinds of non return valve, as far as I am aware.

- The first is typically used in a mains water supply to prevent back
flow of water and is normally based on a spring loaded plunger.
I am not sure that you can get these suitable for the low pressures in
a heating circuit.

- The second type is intended for vertical mounting with an upward
water flow and has a small weight or flap inside. These are typically
used in the pumped heating part of a system when a back boiler is in
use with gravity hot water.

- The third type is based on a metal disc which swings. These can be
mounted horizontally or again vertically on an upward flow.

Look at www.bes.ltd.uk part 7463 and 7464




..andy

To email, substitute .nospam with .gl

"Peter Taylor" wrote in message
...
Bob Mannix wrote

snip stuff where I am sure you are correct but which differs from my
experience! I am in Vale of the White Horse District Council (Oxfordshire)

I've also never heard of using 2 sheets of plasterboard with a 12mm gap.
In the
above examples, 2 staggered layers of 12.5mm wallboard (without skim) will
give
1 hour FR and 2 layers of 15mm Fireline unskimmed will give 1½ hours FR.

As it happens my brother (same county but different district & planning
area) is in the middle of a loft conversion by a national loft conversion
company - I was there yesterday and could see the construction of part of
the stair wall which had the first layer of plasterboard and then battens to
take the second layer - he told me the rest of the walls were the same.

As an aside, having used Fireline plasterboard myself with no problems
(aside from its weight), I can't understand why anyone would use two layers
of ordinary instead, irrespective of the regs!

Thanks for the reference.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)