Before "re-doing" our bathroom I was considering dry-lining the two
external walls with plasterboard, or even insulation-backed
plasterboard. Currently the walls get very cold at this time of year and
this of course is a great condensation producer.

I'm hoping dry-lining will help against this.

However, how far away from the physical brick wall would this put the
tiles? How do I then go about securely fixing things to the wall,
through the dry-lining?

Secondly, can I do anything similar for the ceiling? The ceiling itself
is also suffering from condensation soaking into it, cracking/peeling
the paint and the outer lining paper on the plasterboard, especially
near the external walls and all the area around the extractor fan.

Thanks

etillet wrote:
Before "re-doing" our bathroom I was considering dry-lining the two
external walls with plasterboard, or even insulation-backed
plasterboard. Currently the walls get very cold at this time of year and
this of course is a great condensation producer.

I'm hoping dry-lining will help against this.

However, how far away from the physical brick wall would this put the
tiles? How do I then go about securely fixing things to the wall,
through the dry-lining?

Secondly, can I do anything similar for the ceiling? The ceiling itself
is also suffering from condensation soaking into it, cracking/peeling
the paint and the outer lining paper on the plasterboard, especially
near the external walls and all the area around the extractor fan.

I'm doing the not unrelated task of insulating my whole house.

If I was doing this, and making no comment about any regulations which
may apply.

I would first get enough sheets of 50mm kingspan to cover the entire
bathroom walls + ceiling area. They are around 20 quid a sheet.

Then drill the brick with 38mm holes (diamond core drills are cheap and
fun) to some 50mm or so.

Into this, cement 5" or so lengths of 1"*1" timber.

This is every 400mm or so.
Over this goes a framework of 19*38mm (or so) lattice, fixed to floor
and ceiling, and all of the fixings.

Thence the (foiled) plasterboard. (I foiled my own, as it was cheaper)

There is a small cavity 1-2cm behind the kingspan, and this should be
ventilated to the outside, to prevent damp.

The fan _must_ dump its air outside the wall, not into the cavity.

Also, the cavity shoudl be sealed from the rest of the house, as
otherwise it'll cause condensation behind it from the warm moist air
behind it.

You lose maybe 50mm + 19mm + 15mm +12mm = 100mm of space on each wall.
If I had shares in No More Nails, or some other company, I'd lose the
lattice, and glue the plasterboard to the kingspan.
The kingspan is secured to the wall with dot and dab.
This gives more like 75mm, but is more difficult to fix anything to
securely.

Do note that around a dozen nails through the kingspan halves its
effectiveness.

This will make the bathroom pretty toasty warm.

I'd guess for a 8feet cube bathroom, with 2 external walls, you'd be
looking at a couple of hundred extra or so, for the insulation.

It can be done with rockwool, this is cheaper, though more annoying.
Also, will need deeper rockwool to get teh same result.

Ian Stirling wrote:
etillet wrote:
Before "re-doing" our bathroom I was considering dry-lining the two
external walls with plasterboard, or even insulation-backed
plasterboard. Currently the walls get very cold at this time of year
and this of course is a great condensation producer.

I'm hoping dry-lining will help against this.

However, how far away from the physical brick wall would this put the
tiles? How do I then go about securely fixing things to the wall,
through the dry-lining?

Secondly, can I do anything similar for the ceiling? The ceiling
itself is also suffering from condensation soaking into it,
cracking/peeling the paint and the outer lining paper on the
plasterboard, especially near the external walls and all the area
around the extractor fan.

I'm doing the not unrelated task of insulating my whole house.

If I was doing this, and making no comment about any regulations which
may apply.

I would first get enough sheets of 50mm kingspan to cover the entire
bathroom walls + ceiling area. They are around 20 quid a sheet.

Then drill the brick with 38mm holes (diamond core drills are cheap
and fun) to some 50mm or so.

Into this, cement 5" or so lengths of 1"*1" timber.


Can you explain what's going on here?
Are you coredrilling 38mm diameter holes out, knocking inch timbers in and
using these for affixing studding to the wall?

This is every 400mm or so.
Over this goes a framework of 19*38mm (or so) lattice, fixed to floor
and ceiling, and all of the fixings.

Thence the (foiled) plasterboard. (I foiled my own, as it was cheaper)

There is a small cavity 1-2cm behind the kingspan, and this should be
ventilated to the outside, to prevent damp.

Where does the kingspan fit into the above contraption?


The fan _must_ dump its air outside the wall, not into the cavity.

Also, the cavity shoudl be sealed from the rest of the house, as
otherwise it'll cause condensation behind it from the warm moist air
behind it.

You lose maybe 50mm + 19mm + 15mm +12mm = 100mm of space on each wall.
If I had shares in No More Nails, or some other company, I'd lose the
lattice, and glue the plasterboard to the kingspan.
The kingspan is secured to the wall with dot and dab.
This gives more like 75mm, but is more difficult to fix anything to
securely.

Do note that around a dozen nails through the kingspan halves its
effectiveness.

This will make the bathroom pretty toasty warm.

I'd guess for a 8feet cube bathroom, with 2 external walls, you'd be
looking at a couple of hundred extra or so, for the insulation.


and another couple of hundred for the timber, coredrills and all the rest of
it, per room

It can be done with rockwool, this is cheaper, though more annoying.
Also, will need deeper rockwool to get teh same result.

3X2 scant, drilled, screwed with 100mm screws, rockwool, plasterboard and
skim...new houses are only built with rockwool/fibreglass insulation and
they come up to building regs

On 15 Nov 2006 17:33:08 GMT Ian Stirling wrote :
Then drill the brick with 38mm holes (diamond core drills are cheap and
fun) to some 50mm or so.

Into this, cement 5" or so lengths of 1"*1" timber.

Personally I'd be unhappy about cementing bits of timber into a solid
wall which is going to be very cold given the new insulation: too much
risk of damp and decay for my liking.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk

Phil L wrote:
Ian Stirling wrote:
etillet wrote:
Before "re-doing" our bathroom I was considering dry-lining the two
external walls with plasterboard, or even insulation-backed
plasterboard. Currently the walls get very cold at this time of year
and this of course is a great condensation producer.

I'm hoping dry-lining will help against this.

However, how far away from the physical brick wall would this put the
tiles? How do I then go about securely fixing things to the wall,
through the dry-lining?

Secondly, can I do anything similar for the ceiling? The ceiling
itself is also suffering from condensation soaking into it,
cracking/peeling the paint and the outer lining paper on the
plasterboard, especially near the external walls and all the area
around the extractor fan.

I'm doing the not unrelated task of insulating my whole house.

If I was doing this, and making no comment about any regulations which
may apply.

I would first get enough sheets of 50mm kingspan to cover the entire
bathroom walls + ceiling area. They are around 20 quid a sheet.

Then drill the brick with 38mm holes (diamond core drills are cheap
and fun) to some 50mm or so.

Into this, cement 5" or so lengths of 1"*1" timber.

Can you explain what's going on here?
Are you coredrilling 38mm diameter holes out, knocking inch timbers in and
using these for affixing studding to the wall?

Pretty much, though concreting in the inch timbers. Works well IME.

In my case, it's a pretty good fixing into friable sandstone, it was
this or replace the hammered in wooden pegs, or use other relatively
expensive fixing method - the coredrill has cost me 14p/hole so far, and
dropping.

This is every 400mm or so.
Over this goes a framework of 19*38mm (or so) lattice, fixed to floor
and ceiling, and all of the fixings.

Thence the (foiled) plasterboard. (I foiled my own, as it was cheaper)

There is a small cavity 1-2cm behind the kingspan, and this should be
ventilated to the outside, to prevent damp.

Where does the kingspan fit into the above contraption?

Offer up to the pegs, tap firmly, cut holes with a knife, push on,
attach battens, job done.

It's based on what's been holding the plasterboard up without issue for
20 yearsish in my house. (not installed by me.

The fan _must_ dump its air outside the wall, not into the cavity.

Also, the cavity shoudl be sealed from the rest of the house, as
otherwise it'll cause condensation behind it from the warm moist air
behind it.

You lose maybe 50mm + 19mm + 15mm +12mm = 100mm of space on each wall.
If I had shares in No More Nails, or some other company, I'd lose the
lattice, and glue the plasterboard to the kingspan.
The kingspan is secured to the wall with dot and dab.
This gives more like 75mm, but is more difficult to fix anything to
securely.

Do note that around a dozen nails through the kingspan halves its
effectiveness.

This will make the bathroom pretty toasty warm.

I'd guess for a 8feet cube bathroom, with 2 external walls, you'd be
looking at a couple of hundred extra or so, for the insulation.


and another couple of hundred for the timber, coredrills and all the rest of
it, per room

Hokay, rough BOM.

For a bathroom, 2 2.4m*2.4m walls, one 2.4m*2.4m ceiling.
With 400mm spaced timber, that's around 7 per wall, or 33m in both
directions.
Call it a hundred meters, or 30 quid, 50 quid including some for the top
and bottom.
Coredrill is 15 quid, and will easily do the 40 or so holes.
A bucket of concrete is a poundish, screws another,

It can be done with rockwool, this is cheaper, though more annoying.
Also, will need deeper rockwool to get teh same result.

3X2 scant, drilled, screwed with 100mm screws, rockwool, plasterboard and
skim...new houses are only built with rockwool/fibreglass insulation and
they come up to building regs

Sure - taking 50mm of extra room up with rockwool is going to be quite
noticable in some bathrooms though.

100mm screws going all the way through hurt your overall insulation
quite a lot.

Tony Bryer wrote:
On 15 Nov 2006 17:33:08 GMT Ian Stirling wrote :
Then drill the brick with 38mm holes (diamond core drills are cheap and
fun) to some 50mm or so.

Into this, cement 5" or so lengths of 1"*1" timber.

Personally I'd be unhappy about cementing bits of timber into a solid
wall which is going to be very cold given the new insulation: too much
risk of damp and decay for my liking.

Its fine if you put a vapour barrrier between the room and the wood.

Ian Stirling wrote:

etillet wrote:
Before "re-doing" our bathroom I was considering dry-lining the two
external walls with plasterboard, or even insulation-backed
plasterboard. Currently the walls get very cold at this time of year and
this of course is a great condensation producer.

I'm hoping dry-lining will help against this.

However, how far away from the physical brick wall would this put the
tiles? How do I then go about securely fixing things to the wall,
through the dry-lining?

Secondly, can I do anything similar for the ceiling? The ceiling itself
is also suffering from condensation soaking into it, cracking/peeling
the paint and the outer lining paper on the plasterboard, especially
near the external walls and all the area around the extractor fan.

I'm doing the not unrelated task of insulating my whole house.

If I was doing this, and making no comment about any regulations which
may apply.

I would first get enough sheets of 50mm kingspan to cover the entire
bathroom walls + ceiling area. They are around 20 quid a sheet.

Then drill the brick with 38mm holes (diamond core drills are cheap and
fun) to some 50mm or so.

Into this, cement 5" or so lengths of 1"*1" timber.

This is every 400mm or so.
Over this goes a framework of 19*38mm (or so) lattice, fixed to floor
and ceiling, and all of the fixings.

Thence the (foiled) plasterboard. (I foiled my own, as it was cheaper)

There is a small cavity 1-2cm behind the kingspan, and this should be
ventilated to the outside, to prevent damp.

The fan _must_ dump its air outside the wall, not into the cavity.

Also, the cavity shoudl be sealed from the rest of the house, as
otherwise it'll cause condensation behind it from the warm moist air
behind it.

You lose maybe 50mm + 19mm + 15mm +12mm = 100mm of space on each wall.
If I had shares in No More Nails, or some other company, I'd lose the
lattice, and glue the plasterboard to the kingspan.
The kingspan is secured to the wall with dot and dab.
This gives more like 75mm, but is more difficult to fix anything to
securely.

Do note that around a dozen nails through the kingspan halves its
effectiveness.

This will make the bathroom pretty toasty warm.

I'd guess for a 8feet cube bathroom, with 2 external walls, you'd be
looking at a couple of hundred extra or so, for the insulation.

It can be done with rockwool, this is cheaper, though more annoying.
Also, will need deeper rockwool to get teh same result.

Just done something similar, but no way could I lose that much space. I
glued 25mm celotex/kingspan to the wall, put 12mm cement board inside
that and screwed the whole thing into the wall with 100mm frame fixings
at intervals. Cement board will be tiled. Some cold bridging for the
fixings obviously, but the plastic around the screw should help. No
cavity between wall and insulation (gasp !) - no space for one. Since
the celotex provides vapour barrier, the outside wall is not rendered,
and the celotax is hard against the wall, I'm not too worried about the
condensation thing. I mean you don't have a cavity between wet plaster
and the wall - it's stuck to it ! I would be bothered if using rockwool
however.
Obviously an extractor fan to remove water vapour is required in a
bathroom.
Simon.

On Wed, 15 Nov 2006 22:20:51 +0000 The Natural Philosopher wrote :
Personally I'd be unhappy about cementing bits of timber into a solid
wall which is going to be very cold given the new insulation: too
much risk of damp and decay for my liking.

Its fine if you put a vapour barrrier between the room and the wood.

It will depend on the wall but if it's porous it will soak up driving rain
which will evaporate more slowly if the wall is cold.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk

Well, Simon has hit the nail on the head with his suggestion of an
extractor fan. Most old houses have problems with modern
bathing/showering changes. The amount of steam far exceeds that from
even 20 years ago. An extractor will usually help and also prevent the
horrible black mould appearing.

That said if you want to increase the warmth of the room then by all
means dryline the room. I would use 50mm battons nailed or screwed to
the wall at 400 or 600 centres with kingspan/celotex insulation in
between (I would put 100mm in new property, but 50mm will see a huge
improvement). Then be sure to use foil backed plasterboard. I like to
use plastic frame fixers with the floating piston inside to fix battons
to the wall.

Calum Sabey
(NewArk Traditional Kitchens 01556 690544)

wrote:
Well, Simon has hit the nail on the head with his suggestion of an
extractor fan. Most old houses have problems with modern
bathing/showering changes. The amount of steam far exceeds that from
even 20 years ago. An extractor will usually help and also prevent the
horrible black mould appearing.

That said if you want to increase the warmth of the room then by all
means dryline the room. I would use 50mm battons nailed or screwed to
the wall at 400 or 600 centres with kingspan/celotex insulation in
between (I would put 100mm in new property, but 50mm will see a huge
improvement). Then be sure to use foil backed plasterboard. I like to
use plastic frame fixers with the floating piston inside to fix battons
to the wall.

Calum Sabey
(NewArk Traditional Kitchens 01556 690544)


Frankly I solved all condensation in one solid wall property bathroom
by lining with 3mm cork.

But what you are suggesting is infinitely better.

Will get the room up to modern insulation standards

And the fan is pretty essential too.

On Fri, 17 Nov 2006 11:04:58 +0000 The Natural Philosopher wrote :
Frankly I solved all condensation in one solid wall property
bathroom by lining with 3mm cork.

But what you are suggesting is infinitely better.

Will get the room up to modern insulation standards

At the price of making it significantly smaller (which may or may
not be significant in this particular case).

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk

Tony Bryer wrote:
On Fri, 17 Nov 2006 11:04:58 +0000 The Natural Philosopher wrote :
Frankly I solved all condensation in one solid wall property
bathroom by lining with 3mm cork.

But what you are suggesting is infinitely better.

Will get the room up to modern insulation standards

At the price of making it significantly smaller (which may or may
not be significant in this particular case).

And a lot warmer.

Fortunately, in my bathrooms case, there is an under-windowsill void,
which I can open up in my case, for extra storage, which will mean the
bathroom has more storage, and more usable space in afterwards.

I'm also considering simply setting the temperature in there 5C higher
than the rest of the house to help with eliminating any trace of damp,
and have nice warm bathroom furniture.

Often if you're doing this sort of stuff, there are ways to better
arrange the space.