Just had a bloke round about cavity wall insualtion and I've been told
that I can't have it. It's a stone built property with an inner leaf of
brickwork. Apparently because the inner side of the stone is jagged it
can cause damp problems. I'm thinking that I'd like to insulate from
the inside now so may get in touch with the plasterer who is due round
next week.

Can anyone please tell me...

What are my options? For ease would rather use dot and dab
plasterboard. How much is it? Is it worth it? How does it compare to
cavity wall insulation?

Cheers,
Matt

RatRibs73 wrote:
Just had a bloke round about cavity wall insualtion and I've been told
that I can't have it. It's a stone built property with an inner leaf of
brickwork. Apparently because the inner side of the stone is jagged it
can cause damp problems. I'm thinking that I'd like to insulate from
the inside now so may get in touch with the plasterer who is due round
next week.

Can anyone please tell me...

What are my options? For ease would rather use dot and dab
plasterboard. How much is it? Is it worth it? How does it compare to
cavity wall insulation?

Cheers,
Matt

I know what I would do, and thats frame the inside with 2x2, packed out
using a ply membrane to keep the damp out, and using spacers of scrap to
get it true, infill with Celotex, tape up firmly with Al. tape, and
slap 12mm foil backed plasterboard on the inside, skim and paint.
After laying in new cables of course..and pipes where appropriate.

I guess you could slap up insulation backed board with gobs of no nails
or whatever..but its a bit of a hack..

Cheers,

Whats ply membrane, celotex and AI tape. Time may be a problem with
this solution. Plasterer is coming round Thursday.

Is the cost of doing this worth it?

"RatRibs73" wrote in message
oups.com...
Just had a bloke round about cavity wall insualtion and I've been told
that I can't have it. It's a stone built property with an inner leaf of
brickwork. Apparently because the inner side of the stone is jagged it
can cause damp problems. I'm thinking that I'd like to insulate from
the inside now so may get in touch with the plasterer who is due round
next week.

The inside jagged? That is new one on me. The only way you can get damp is
if the outer wall is porous in some way.

On 2 Mar 2006 04:24:15 -0800, "RatRibs73" wrote:

Cheers,

Whats ply membrane, celotex and AI tape. Time may be a problem with
this solution. Plasterer is coming round Thursday.

Is the cost of doing this worth it?

With energy costs up 70% in the last year, I say yes.
50mm Celotex will give terrific insulation. Maybe explain the
situation to the plasterer, he may well have come accross this problem
before.

RatRibs73 wrote:
Cheers,

Whats ply membrane, celotex and AI tape. Time may be a problem with
this solution. Plasterer is coming round Thursday.


Celotex is a stiff polyisocyanurate foam board with foil on both sides.
Its rigid, its easily cut and it has twice the insulation properties of
anything else. You wedge it between timber studwork, and use aluminium
tape over it all to create a water and draught proof seal.

Ply membrane is a typo. damp proof membrane - usually polythene.


Is the cost of doing this worth it?


Absolutely. Turns chilly rooms into cosy rooms.

Lobster wrote:
The Natural Philosopher wrote:
RatRibs73 wrote:

anything else. You wedge it between timber studwork, and use aluminium
tape over it all to create a water and draught proof seal.

I didn't know that (the Al tape bit) - makes sense, and glad I found
out as I'm doing exactly this job at the moment (qv my recent query on
drylining a kitchen).

Ply membrane is a typo. damp proof membrane - usually polythene.

Heh, I was scratching my head over the ply membrane! But do you really
need the DPM anyway if you have a clear air gap between the studwork
and the wall? (And the insulation is foil-backed?)

David

No, but belt and braces, and you have to fix the studs to
something..typically what you want is surface finish, then vapour
barrier (the aluminium tape, and the celotex facing) then studs and
celotex matrix for insulation. At this point you get cold and
condensation make take place in the gap..so you want to try and both
keep the studs clear of damp wall, and also allow perhaps moisture to
permeate outwards through the wall - or provide ventilation (airbrick etc)

Its a fine point. If the celotex and al tape is good, then no internal
moisture will penetrate, and the only damp will come in from the
outside, and can leave the same way. Then a poly membrane will keep it
away from the cavity.

OTOH if you HAVE got moisture from the room seeping in, then the last
thing you want is to trap it in the wall..

The Natural Philosopher wrote:

Absolutely. Turns chilly rooms into cosy rooms.

would it also not turn the inside of a house into an oven in the summer?

--
http://gymratz.co.uk - Best Gym Equipment & Bodybuilding Supplements UK.
http://trade-price-supplements.co.uk - TRADE PRICED SUPPLEMENTS for ALL!
http://fitness-equipment-uk.com - UK's No.1 Fitness Equipment Suppliers.
http://Water-Rower.co.uk - Worlds best prices on the Worlds best Rower.

""Pet @ www.gymratz.co.uk ;¬)"" wrote in message
news
The Natural Philosopher wrote:

Absolutely. Turns chilly rooms into cosy rooms.

would it also not turn the inside of a house into an oven in the summer?

Nope. It also keeps the heat out too. Heats and cools.

In article
"Pet @ www.gymratz.co.uk ;¬)" wrote:
The Natural Philosopher wrote:

Absolutely. Turns chilly rooms into cosy rooms.

would it also not turn the inside of a house into an oven in the summer?

Where do you think most of the heat comes from in the summer?

Pet @ www.gymratz.co.uk ;¬) wrote:
The Natural Philosopher wrote:

Absolutely. Turns chilly rooms into cosy rooms.

would it also not turn the inside of a house into an oven in the summer?


No. Does the inside of your insulated fridge turn into a roasting oven
in summer?

It will actually tend to cool the interior in summer. As the exterior
brickwork can get very warm indeed.

Only in the sense that you will lose thermal mass, may there be a
problem - i.e. overnight the brickwork will cool, and that may be
transmitted to the interior during part of the early day in an
uninsulated house.

The solution is to have mass - a concrete floor, or brick chimney -
inside the house...where it can act to stabilise temperature

In message , The Natural
Philosopher writes

Ply membrane is a typo. damp proof membrane - usually polythene.
Heh, I was scratching my head over the ply membrane! But do you
really
need the DPM anyway if you have a clear air gap between the studwork
and the wall? (And the insulation is foil-backed?)
David

No, but belt and braces, and you have to fix the studs to
something..typically what you want is surface finish, then vapour
barrier (the aluminium tape, and the celotex facing) then studs and
celotex matrix for insulation. At this point you get cold and
condensation make take place in the gap..so you want to try and both
keep the studs clear of damp wall, and also allow perhaps moisture to
permeate outwards through the wall - or provide ventilation (airbrick etc)

Umm.. I've been consorting with architects and they seem to have latched
on to *insulating the inside* in a big way.

OK for plain walls (so long as you have floor standing shelves) but I'm
trying to repair and insulate some Victorian barns which have a mix of
9" dwarf walls topped with 4" studwork and exterior feather edge
boarding. To retain any visual interest in the construction I need to
insulate on the outside.

They have suggested insulating the brickwork internally and putting
insulation between the timbers. Is condensation likely to be an issue?

I have to rebuild the wall anyway and would find cavity work easier than
9" solid.

Any pointers to how others have approached this problem?

regards
--
Tim Lamb

"Tim Lamb" wrote in message
...
In message , The Natural Philosopher
writes

Any pointers to how others have approached this problem?

regards
--
Tim Lamb
..
Why don't you look at how we build wood frame houses in Canada!

These commonly have 2 by 4 or 2 by 6 wood stud walls which are heavily
insulated.

There is much emphasis on a well sealed non-permeable vapour/air barrier on
the 'inside' or warm side of the wall structure, including careful vapour
sealing around electrical outlets etc. in exterior walls. The most rigid
standard, R-2000 also requires the use of an air-exchange which exhausts
stale air, brings in fresh air and in the process recovers much of the heat
from the outgoing air.

On the outside of the wall underneath any 'cladding', including brickwork
which here is rarely used structurally, the use of a permeable 'building
paper' or product such Tyvek is normal/required. Outside finishes can be
wood siding, vinyl siding, occasionally metal and more recently a product
that looks like wood clap-board (lap-siding) but is made of cement. Very
occasionally stucco. See note:

One other thing that I recall for this particular climate (eastern maritime
Canada) which is wetter and generally colder (for longer) than most oft the
UK, is that 'not more than one third of the total insulation should be
inside the vapour barrier. The reason being to not allow warm and therefore
moisture laden air to permeate into the wall and condense at some point
within it causing wet insulation and/or rot and mould.

We have used vapour barriers and Al. foil in the walls and insulated
ceilings of both house we have built and lived in since 1960. Adhering to
the principle and standards espoused by CMHC (Canadian Mortgage and Housing)
has certainly been worthwhile. No rot, minimum draughts, low maintenance,
little paint peeling etc.

BTW it's wise also make sure of sealed ceilings and a well ventilated attic;
failure to do so can cause attic condensation and roof rot! IIRC the minimum
'distributed' venting is 3 sq.feet per 1000 sq. ft of area, 0.3% (by area
not volume). Most house have much more than that, with frequently or
continuously vented soffits and/or gable-end and/or roof vents.

Note: A neighbours house one year older than ours, later had some sort of
sprayed on coating with a slightly rough 'stucco like' texture instead of
stain or breathable-permeable paint. It was applied onto the conventional
wooden clapboard (lap siding). Once completed the previous owner claiming
that he had solved the repainting problem for life. He's dead and gone, rest
his soul.
But the present owner reports that the sprayed on finish is cracking and
peeling possibly due to moisture finding it's way out through the walls? I
always wondered about the validity of the inside vapour barrier since
original owner did much of the building himself; as did we all in those
days! Present owner reports some evidence of mould in a few places in some
walls. Also the slightly rough finish gets grimy, suggesting that even if
it survives the house exterior will have to be repainted anyway.

Our house has pine clapboard siding and again this summer will need
restaining (always use a permeable stain not paint) and some repainting of
the trim. This will be for about the fourth time in 36 years; I will most
likely again do it myself (age 72) using a couple of trestles and planks for
most of it. Happy to report that this house passed insurance inspection
recently and the addition of a couple of requirements will reduce the annual
insurance premium somewhat.

On Sun, 5 Mar 2006 19:03:02 -0330 Terry wrote :
These commonly have 2 by 4 or 2 by 6 wood stud walls which are heavily
insulated.

Particularly on the latter do you not get problems with the studs acting
as cold bridges and causing pattern staining?

--
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
[Latest version QSEDBUK 1.12 released 8 Dec 2005]

"Terry" wrote in message
...

"Tim Lamb" wrote in message
...
In message , The Natural
Philosopher writes

Any pointers to how others have approached this problem?

regards
--
Tim Lamb
.
Why don't you look at how we build wood frame houses in Canada!

They make the best. The Canadians have the R2000 standard, which is one the
most advanced in the world, if not the most. The Canadians, say "build
tight, ventilate right". The Canadians are implementing the R2000 standard
in the UK and Japan. Canadian companies have be involved with UK companies,
as the UK companies just don't have the
skills levels, or can't concentrate long enough to carry out detailed work.

These commonly have 2 by 4 or 2 by 6 wood stud walls which are heavily
insulated.

There is much emphasis on a well sealed non-permeable vapour/air barrier
on the 'inside' or warm side of the wall structure, including careful
vapour sealing around electrical outlets etc. in exterior walls. The most
rigid standard, R-2000 also requires the use of an air-exchange which
exhausts stale air, brings in fresh air and in the process recovers much
of the heat from the outgoing air.

The exchanger is not manadtory but is generally used.

On the outside of the wall underneath any 'cladding', including brickwork
which here is rarely used structurally, the use of a permeable 'building
paper' or product such Tyvek is normal/required. Outside finishes can be
wood siding, vinyl siding, occasionally metal and more recently a product
that looks like wood clap-board (lap-siding) but is made of cement. Very
occasionally stucco. See note:

One other thing that I recall for this particular climate (eastern
maritime Canada) which is wetter and generally colder (for longer) than
most oft the UK, is that 'not more than one third of the total insulation
should be inside the vapour barrier. The reason being to not allow warm
and therefore moisture laden air to permeate into the wall and condense at
some point within it causing wet insulation and/or rot and mould.

We have used vapour barriers and Al. foil in the walls and insulated
ceilings of both house we have built and lived in since 1960. Adhering to
the principle and standards espoused by CMHC (Canadian Mortgage and
Housing) has certainly been worthwhile. No rot, minimum draughts, low
maintenance, little paint peeling etc.

BTW it's wise also make sure of sealed ceilings and a well ventilated
attic; failure to do so can cause attic condensation and roof rot! IIRC
the minimum 'distributed' venting is 3 sq.feet per 1000 sq. ft of area,
0.3% (by area not volume). Most house have much more than that, with
frequently or continuously vented soffits and/or gable-end and/or roof
vents.

Note: A neighbours house one year older than ours, later had some sort of
sprayed on coating with a slightly rough 'stucco like' texture instead of
stain or breathable-permeable paint. It was applied onto the conventional
wooden clapboard (lap siding). Once completed the previous owner claiming
that he had solved the repainting problem for life. He's dead and gone,
rest his soul.
But the present owner reports that the sprayed on finish is cracking and
peeling possibly due to moisture finding it's way out through the walls? I
always wondered about the validity of the inside vapour barrier since
original owner did much of the building himself; as did we all in those
days! Present owner reports some evidence of mould in a few places in some
walls. Also the slightly rough finish gets grimy, suggesting that even if
it survives the house exterior will have to be repainted anyway.

Our house has pine clapboard siding and again this summer will need
restaining (always use a permeable stain not paint) and some repainting of
the trim. This will be for about the fourth time in 36 years; I will most
likely again do it myself (age 72) using a couple of trestles and planks
for most of it. Happy to report that this house passed insurance
inspection recently and the addition of a couple of requirements will
reduce the annual insurance premium somewhat.

Terry wrote:
"Tim Lamb" wrote in message
...
In message , The Natural Philosopher
writes

Any pointers to how others have approached this problem?

regards
--
Tim Lamb
.
Why don't you look at how we build wood frame houses in Canada!

These commonly have 2 by 4 or 2 by 6 wood stud walls which are heavily
insulated.

There is much emphasis on a well sealed non-permeable vapour/air barrier on
the 'inside' or warm side of the wall structure, including careful vapour
sealing around electrical outlets etc. in exterior walls. The most rigid
standard, R-2000 also requires the use of an air-exchange which exhausts
stale air, brings in fresh air and in the process recovers much of the heat
from the outgoing air.

On the outside of the wall underneath any 'cladding', including brickwork
which here is rarely used structurally, the use of a permeable 'building
paper' or product such Tyvek is normal/required. Outside finishes can be
wood siding, vinyl siding, occasionally metal and more recently a product
that looks like wood clap-board (lap-siding) but is made of cement. Very
occasionally stucco. See note:

One other thing that I recall for this particular climate (eastern maritime
Canada) which is wetter and generally colder (for longer) than most oft the
UK, is that 'not more than one third of the total insulation should be
inside the vapour barrier. The reason being to not allow warm and therefore
moisture laden air to permeate into the wall and condense at some point
within it causing wet insulation and/or rot and mould.

We have used vapour barriers and Al. foil in the walls and insulated
ceilings of both house we have built and lived in since 1960. Adhering to
the principle and standards espoused by CMHC (Canadian Mortgage and Housing)
has certainly been worthwhile. No rot, minimum draughts, low maintenance,
little paint peeling etc.

BTW it's wise also make sure of sealed ceilings and a well ventilated attic;
failure to do so can cause attic condensation and roof rot! IIRC the minimum
'distributed' venting is 3 sq.feet per 1000 sq. ft of area, 0.3% (by area
not volume). Most house have much more than that, with frequently or
continuously vented soffits and/or gable-end and/or roof vents.

Note: A neighbours house one year older than ours, later had some sort of
sprayed on coating with a slightly rough 'stucco like' texture instead of
stain or breathable-permeable paint. It was applied onto the conventional
wooden clapboard (lap siding). Once completed the previous owner claiming
that he had solved the repainting problem for life. He's dead and gone, rest
his soul.
But the present owner reports that the sprayed on finish is cracking and
peeling possibly due to moisture finding it's way out through the walls? I
always wondered about the validity of the inside vapour barrier since
original owner did much of the building himself; as did we all in those
days! Present owner reports some evidence of mould in a few places in some
walls. Also the slightly rough finish gets grimy, suggesting that even if
it survives the house exterior will have to be repainted anyway.

Our house has pine clapboard siding and again this summer will need
restaining (always use a permeable stain not paint) and some repainting of
the trim. This will be for about the fourth time in 36 years; I will most
likely again do it myself (age 72) using a couple of trestles and planks for
most of it. Happy to report that this house passed insurance inspection
recently and the addition of a couple of requirements will reduce the annual
insurance premium somewhat.


Not just canada. This is essentially what my 2001 UK house is built like.

Tony Bryer wrote:
On Sun, 5 Mar 2006 19:03:02 -0330 Terry wrote :
These commonly have 2 by 4 or 2 by 6 wood stud walls which are heavily
insulated.

Particularly on the latter do you not get problems with the studs acting
as cold bridges and causing pattern staining?



Cold bridges yes, pattern staining no.

However if enough insulation is used, the overall U values are good
enough for the regs.

In message , The Natural
Philosopher writes
Tony Bryer wrote:
On Sun, 5 Mar 2006 19:03:02 -0330 Terry wrote :
These commonly have 2 by 4 or 2 by 6 wood stud walls which are
heavily insulated.
Particularly on the latter do you not get problems with the studs
acting as cold bridges and causing pattern staining?



Cold bridges yes, pattern staining no.

However if enough insulation is used, the overall U values are good
enough for the regs.

I had in mind to leave part of the studs visible so staining is not an
issue. The most convenient place for the membrane is between the frame
and the outer insulation. I suppose it would be easy to leave an air gap
behind the boarding. Feather edge is not *airtight*anyway.

The structure would be studs infilled with plasterboard and 25mm
insulation, vapour membrane, 25/50mm exterior insulation, battens (long
screws:-) and feather edge.

This totals around 200mm so fits the architects idea of 9" supporting
brick but means any *nice* brickwork being hidden behind internal
insulation. I'm inclined to do cavity work and put a shelf along the top
to hide the ledge. Somebody will perhaps advise on closing the cavity:-)

Meanwhile I'm off to search the farm for bits of discarded Oak to
replace that rotted by the previous owners ignorance of ventilation.

regards

--
Tim Lamb

In message , Terry
writes

"Tim Lamb" wrote in message
...
In message , The Natural Philosopher
writes

Any pointers to how others have approached this problem?

regards
--
Tim Lamb
.
Why don't you look at how we build wood frame houses in Canada!

These commonly have 2 by 4 or 2 by 6 wood stud walls which are heavily
insulated.

Thank you. An excellent description. The UK does not experience the
extremes of weather found in Canada but we think we win on humidity.

I am interested in the purpose of the permeable paper?

regards

--
Tim Lamb

The Natural Philosopher wrote:
Pet @ www.gymratz.co.uk ;¬) wrote:
The Natural Philosopher wrote:

Absolutely. Turns chilly rooms into cosy rooms.

would it also not turn the inside of a house into an oven in the summer?


No. Does the inside of your insulated fridge turn into a roasting oven
in summer?


But doesn't a fridge stay cold actively? The only way an insulated room
could cool itself when warm outside would be air con surely.


It will actually tend to cool the interior in summer. As the exterior
brickwork can get very warm indeed.

Only in the sense that you will lose thermal mass, may there be a
problem - i.e. overnight the brickwork will cool, and that may be
transmitted to the interior during part of the early day in an
uninsulated house.

The solution is to have mass - a concrete floor, or brick chimney -
inside the house...where it can act to stabilise temperature

Tim Lamb wrote:
In message , Terry
writes

"Tim Lamb" wrote in message
...
In message , The Natural
Philosopher
writes

Any pointers to how others have approached this problem?

regards
--
Tim Lamb
.
Why don't you look at how we build wood frame houses in Canada!

These commonly have 2 by 4 or 2 by 6 wood stud walls which are heavily
insulated.

Thank you. An excellent description. The UK does not experience the
extremes of weather found in Canada but we think we win on humidity.

I am interested in the purpose of the permeable paper?

So was I.

It seems to be that water will run down the outside of it, but wind will
not go through it, and moisture can, in time, percolate through it from
inside the walls.

I.e. it ensures that there will be no build up of moisture inside the
walls, whilst providing a showerproof coating.

My walls are

- 12x12 oak frame infilled with 7x3 studwork. On a double brick cavity
wall with rockwool battens inside.

Then layers from the outside:-

Render over mesh, onto 1" battens (airgap behind the render, open at the
base to allow any possible water ingress to drip out I suppose. Then
building paper, then 12" waterproof ply. Then the studwork, with
rockwool filled cavity to foil backed 12mm plasterboard laid over the
softwood studs and TO the oak frame.

In an ideal life I'd have used celotex for even better insulation.

This construction entirely satisfied 2000 building regulations.

The structural strength given by the ply cladding is amazing.

The only drawback is you can feel the whole frame tremble when someone
slams a (very heavy solid oak) exterior door :-)

The exterior could have as easily have had weatherboards instead of the
render/mesh. There is no structural strength in the render - its purely
there to keep he driving rain off.






regards

"The Natural Philosopher" wrote in message
...
Terry wrote:
"Tim Lamb" wrote in message
...
In message , The Natural
Philosopher writes

Any pointers to how others have approached this problem?

regards
--
Tim Lamb
.
Why don't you look at how we build wood frame houses in Canada!

These commonly have 2 by 4 or 2 by 6 wood stud walls which are heavily
insulated.

There is much emphasis on a well sealed non-permeable vapour/air barrier
on the 'inside' or warm side of the wall structure, including careful
vapour sealing around electrical outlets etc. in exterior walls. The most
rigid standard, R-2000 also requires the use of an air-exchange which
exhausts stale air, brings in fresh air and in the process recovers much
of the heat from the outgoing air.

On the outside of the wall underneath any 'cladding', including brickwork
which here is rarely used structurally, the use of a permeable 'building
paper' or product such Tyvek is normal/required. Outside finishes can be
wood siding, vinyl siding, occasionally metal and more recently a product
that looks like wood clap-board (lap-siding) but is made of cement. Very
occasionally stucco. See note:

One other thing that I recall for this particular climate (eastern
maritime Canada) which is wetter and generally colder (for longer) than
most oft the UK, is that 'not more than one third of the total insulation
should be inside the vapour barrier. The reason being to not allow warm
and therefore moisture laden air to permeate into the wall and condense
at some point within it causing wet insulation and/or rot and mould.

We have used vapour barriers and Al. foil in the walls and insulated
ceilings of both house we have built and lived in since 1960. Adhering to
the principle and standards espoused by CMHC (Canadian Mortgage and
Housing) has certainly been worthwhile. No rot, minimum draughts, low
maintenance, little paint peeling etc.

BTW it's wise also make sure of sealed ceilings and a well ventilated
attic; failure to do so can cause attic condensation and roof rot! IIRC
the minimum 'distributed' venting is 3 sq.feet per 1000 sq. ft of area,
0.3% (by area not volume). Most house have much more than that, with
frequently or continuously vented soffits and/or gable-end and/or roof
vents.

Note: A neighbours house one year older than ours, later had some sort of
sprayed on coating with a slightly rough 'stucco like' texture instead of
stain or breathable-permeable paint. It was applied onto the conventional
wooden clapboard (lap siding). Once completed the previous owner claiming
that he had solved the repainting problem for life. He's dead and gone,
rest his soul.
But the present owner reports that the sprayed on finish is cracking and
peeling possibly due to moisture finding it's way out through the walls?
I always wondered about the validity of the inside vapour barrier since
original owner did much of the building himself; as did we all in those
days! Present owner reports some evidence of mould in a few places in
some walls. Also the slightly rough finish gets grimy, suggesting that
even if it survives the house exterior will have to be repainted anyway.

Our house has pine clapboard siding and again this summer will need
restaining (always use a permeable stain not paint) and some repainting
of the trim. This will be for about the fourth time in 36 years; I will
most likely again do it myself (age 72) using a couple of trestles and
planks for most of it. Happy to report that this house passed insurance
inspection recently and the addition of a couple of requirements will
reduce the annual insurance premium somewhat.
Not just canada. This is essentially what my 2001 UK house is built like.

With those single glazed windows you put in?

In message , The Natural
Philosopher writes

I am interested in the purpose of the permeable paper?

So was I.

It seems to be that water will run down the outside of it, but wind
will not go through it, and moisture can, in time, percolate through it
from inside the walls.

Right.

I.e. it ensures that there will be no build up of moisture inside the
walls, whilst providing a showerproof coating.

My walls are

- 12x12 oak frame infilled with 7x3 studwork. On a double brick cavity
wall with rockwool battens inside.


Then layers from the outside:-

Render over mesh, onto 1" battens (airgap behind the render, open at
the base to allow any possible water ingress to drip out I suppose.
Then building paper, then 12" waterproof ply. Then the studwork, with
rockwool filled cavity to foil backed 12mm plasterboard laid over the
softwood studs and TO the oak frame.

When my farmhouse was *re-modelled* the specification was ....feather
edge or cement render on expanded metal over 25mm foil backed insulation
between battens. Then a vapour barrier over the original render (they
had to grit blast off the paint to restore permeability). The 4" stud
work and lath and plaster were left alone. I doubt it would meet current
regulations but it is !"£$%^& warmer than it was:-) I claim to have
originated the tale of the hot water bottle that froze on the bedroom
floor.

In an ideal life I'd have used celotex for even better insulation.

This construction entirely satisfied 2000 building regulations.

The structural strength given by the ply cladding is amazing.

12"?

The only drawback is you can feel the whole frame tremble when someone
slams a (very heavy solid oak) exterior door :-)

Oh. I have been considering an internal steel frame to strengthen a 2
storey barn and wonder if this might be an issue.

The exterior could have as easily have had weatherboards instead of the
render/mesh. There is no structural strength in the render - its purely
there to keep he driving rain off.

Huh! I am rebuilding a redundant cowshed and have found that the
internal render was actually supporting the roof. Around WWII the
ministry of agriculture decreed that dairies should have a white,
washable internal surface. This was most easily achieved by nailing up
mesh, slapping on a coat of the hardest render possible and giving it a
coat of whitewash. What nobody foresaw was the effect of shutting off
ventilation from untreated timber. The Oak studs and sole plate are more
or less intact but the wall plate (pine) has simply disappeared.

regards

--
Tim Lamb