Insulating solid walls
GMM
I know this topic has been covered before but I can't seem to find the
details I have been pondering about and I hope someone might know the
answers. I have never done this before because my current place has
insulated cavity walls but am now moving into a Victorian house with
solid brick.
First of all, yes I know it's covered by building regs but I have no
intention of bothering a BCO with such matters as the final U-values
required are so impractical in terms of depth of insulation that it
would never happen if I went down that route. Somehow I doubt the
insulation police are going to knock on my door to check it out. Oh,
and there's no way I can insulate on the outside, even though that
might well be better.
From a whole range of sources I can see the standard approach
(variants on wall - kingspan/celotex - membrane - plasterboard).
Clearly, the kingspan sits between tanalised studwork that is
protected from damp from the wall by a strip of dpc and/or spacers.
All well and good. (I would look at insulation-backed plasterboard but
this is in a kitchen and the studwork can be arranged to carry wall
units etc).
So, the questions that arise are mostly born of a paranoia about damp
from the wall in the longer term:
Should the plaster be removed from the wall? It adds some insulating
properties but without ventilation could wind up as a big mess behind
the whole thing - crumbling plaster behind the studding could
destabilise the whole thing. On the other hand, removing the plaster
would be a lengthy and dirty process.
How do you space the kingspan from the wall? It clearly shouldn't be
against the brick, should it? I know it will sit snugly between the
timbers if cut properly, but it could become displaced for a number of
reasons. I was thinking of using 50mm kingspan between 68 mm
studding, so there should be an 18mm (or thereabouts) air gap.
Is it bad for the wall in the long term? It seems to me that a
conventional wall should dry (after rain etc) partly because of the
heat from inside driving the water out. With an effective insulation
layer, this effect must surely be reduced, although for all I know
this contribution could be insignificant.
Any information gratefully received as usual!
stuart noble
I have been pondering the possibilities of skimming quite thin layers of
closed cell foam so that the existing dimensions of the rooms can be
maintained. Camping mats appear to be highly efficient, despite the
6-7mm thickness.
Is it worth hacking off just to incorporate that much foam? Can you
plaster directly on to it? Dunno, but I might do a trial this winter
The Natural Philosopher
It clearly shouldn't be
> against the brick, should it? I know it will sit snugly between the
> timbers if cut properly, but it could become displaced for a number of
> reasons. I was thinking of using 50mm kingspan between 68 mm
> studding, so there should be an 18mm (or thereabouts) air gap.
>
surface FROM the kitchen..so no need to 'dry the brickwork out - that
will happen naturally as its porous. You don't even need a DPM except to
protect the studwork from rot. BUT the overall wall humidity will be low
anyway. Most moisture will be fom inside the house if the guttering is
good and the wall is not exposed to massive driving rain for long periods.
You WILL need an extractor fan though to remove moisture explicitly.
> Is it bad for the wall in the long term? It seems to me that a
> conventional wall should dry (after rain etc) partly because of the
> heat from inside driving the water out. With an effective insulation
> layer, this effect must surely be reduced, although for all I know
> this contribution could be insignificant.
>
with moisture. And in any case slightly damp brickwork is no big deal -
only if its so full of water that when and if it freezes it spallates,
is there an issue.
And that can be solved by a waterproof coating on the outside..render or
a paint on sealer. IF its necessary. But mostly it is not.
>
> Any information gratefully received as usual!
units etc, consider MDF not plasterboard. It paints well, tiles well and
is strong enough to screw to. Only downside is it moves..and will crack
at any butt joints. But it comes in 8ft lengths, which is often enough
to span a whole wall, and horizontal joints can be covered in e.g.
units. It also removes the cost and issues of skimming.
Use decorators caulk on the corners to cope with cracking there.
Also, this is a great opportunity to lay surface height sockets for
kettles and microwaves, by simply tacking cables to the wall before
insulating..
I'd simply tape some plastic or foil strips to the wall, whack up some
2x1 or 2x2 studs. infill with 1" or 2" celotex and TAPE OVER COMPLETLY
and then cover in MDF.
caulk that, paint it ,fit electrical socket back plates (these can be
screwed to the brickwork FIRST if the spacing works out OK) and fit the
kitchen around it.
RobertL
...
> intention of bothering a BCO with such matters as the final U-values
> required are so impractical in terms of depth of insulation that it
> would never happen if I went down that route.
the full requirement if that would impact the use of the room too
much. We did this in our house in some places and applied 35mm of
celotex-backed plasterboard instead of the 110mm (IIRC) that was
actually required.
The celotex (or whatever) went direcetly onto the old plaster with no
airgap. See here:
http://www.celotex.co.uk/applications/wall-insulation/solid-masonry-walls-external
Robert
Roger Chapman
>
> I have been pondering the possibilities of skimming quite thin layers of
> closed cell foam so that the existing dimensions of the rooms can be
> maintained. Camping mats appear to be highly efficient, despite the
> 6-7mm thickness.
> Is it worth hacking off just to incorporate that much foam? Can you
> plaster directly on to it? Dunno, but I might do a trial this winter
'hempcrete' (IIRC). A mixture of chopped hemp and lime mortar which
apparently has insulating properties. Unfortunately no one rose to the
bait and I don't currently have a link to my original information which
included a video of a man (wearing rubber gloves) slapping the mixture
onto an old wall before smoothing it off. The sort of rough diy that I
could probably manage.
--
Roger Chapman
stuart noble
I see Gyproc do a 27mm board. I reckon I'd have room for 20mm without
upsetting the levels round doors and windows. Don't know what the u
values would be but my gut instinct is that even 7.5 mm of foam would
have a big impact on typical 9" walls.
Martin Bonner
>
> I know this topic has been covered before but I can't seem to find the
> details I have been pondering about and I hope someone might know the
> answers. I have never done this before because my current place has
> insulated cavity walls but am now moving into a Victorian house with
> solid brick.
>
> First of all, yes I know it's covered by building regs but I have no
> intention of bothering a BCO with such matters as the final U-values
> required are so impractical in terms of depth of insulation that it
> would never happen if I went down that route. Somehow I doubt the
> insulation police are going to knock on my door to check it out. Oh,
> and there's no way I can insulate on the outside, even though that
> might well be better.
of about 2 atm, and regs call for something like 0.25 (off the top of
my head) for new build.
> From a whole range of sources I can see the standard approach
> (variants on wall - kingspan/celotex - membrane - plasterboard).
> Clearly, the kingspan sits between tanalised studwork that is
> protected from damp from the wall by a strip of dpc and/or spacers.
kingspan-battens-plasterboard.
See http://www.celotex.co.uk/applications/wall-insulation/solid-masonry-walls-internal
(you have to sign up for the download annoyingly).
The problem with insulation *between* studwork is that heat flows
through the studwork.
A system with 9" brick, 70mm PIR foam, 25mm battens, and 12mm
plasterboard/MDF/plywood should get you to current regs.
> So, the questions that arise are mostly born of a paranoia about damp
> from the wall in the longer term:
counter-intuitive (it's dry inside and wet outside), but the point is
that "warm and fairly dry" air contains more water that "cool and
damp" air. When your steamy kitchen air passes through the
insulation, the steam will condense and cause damp.
The solution is to be careful about the vapour control layer. The
insulation will have a foil layer (which should be on the inside), you
carefully seal this with tape ... and all should be well.
The Natural Philosopher
your gut is correct.
even 3mm of foam makes huge difference
The Natural Philosopher
yes, but its less width overall.
js.b1
a) 5% rule - where you would lose more than 5% of the floor area, not
difficult in a tiny box room which even victorian houses may have
and
b) Reasonably Practical - where a door hinges against the outer wall
leaving you perhaps 25-30mm of space for insulation & plaster, you are
not expected to demolish the house to force 50mm insulation in - nor
spend ridiculous sums on the special insulations.
There are many ways of fixing.
Studwork is a lot of hassle and people tend to just hammer-fix
insulated-plasterboard directly to the wall with special oversized
washers and skim over. I believe that is most popular with Celotex
Technical at the moment, along with fixing battens OVER celotex which
is foil-taped, then insulation between those slim battens, then
plasterboard over the top. This has the benefit of creating a more air
tight surface at the solid brick wall.
Solid brick means some do not recommend dot-n-dab adhesion methods,
but it comes down to exactly how dry - triple engineering brick with
paper wide mortar is pretty dry unless you have a guttering leak.
So rule #1 is fix the guttering before you stick insulation up, ie,
fix the damp now rather than try to make it go away. Then rule #2 is
buy/hire a cheap waterproof video camera and stuff it up all your
drains to check none dropped, cracked, full of tree roots. Then rule
#3 is have a nosey around for any leaking water main, ie, newly
forming cracks or boggy areas.
Insulation is everything, it pays back every year.
Mess... did someone mention mess... do the main living area first and
as well as you can, ie, where you will get the biggest payback re
likely temperature. For example a living room may be 22oC, but a
unused box room may be 12oC. Celotex etc are not cheap and you can
always leave space to add more later if need be. "Seconds" are your
friend, and DO foil tape the joints as necessary.
GMM
wrote:
around, imagining water from outside to be the bigger problem!
The MDF suggestion is interesting: I had been thinking of organising
things so that hardly any of the plasterboard joints were on show, but
hadn't thought of MDF as I have normally found that PB makes a pretty
good finish when just painted. The wall in question has a window
taking up the centre third and the space each side will be covered by
base units, tiles or something (incorporating sockets as you say),
then wall units, so it's only the edges of the windows and the wall
above the wall units that will show.
The Natural Philosopher
I improved condensation on a solid brick kitchen with 3mm CORK TILES.
That's how little you need to make a difference.
celotex is 50 times better an insulator than brick.
So you can halve U values with just 1/50th the depth of the brick wall.
If that's 9", that's about 5mm or less
GMM
> On Sep 14, 10:34 am, GMM <Han...@dsl.pipex.com> wrote:
>
> > Hello folks.
>
> > I know this topic has been covered before but I can't seem to find the
> > details I have been pondering about and I hope someone might know the
> > answers. I have never done this before because my current place has
> > insulated cavity walls but am now moving into a Victorian house with
> > solid brick.
>
> > First of all, yes I know it's covered by building regs but I have no
> > intention of bothering a BCO with such matters as the final U-values
> > required are so impractical in terms of depth of insulation that it
> > would never happen if I went down that route. Somehow I doubt the
> > insulation police are going to knock on my door to check it out. Oh,
> > and there's no way I can insulate on the outside, even though that
> > might well be better.
>
> Well, anything's better than nothing. You'll be looking at a U value
> of about 2 atm, and regs call for something like 0.25 (off the top of
> my head) for new build.
>
>
>
> > From a whole range of sources I can see the standard approach
> > (variants on wall - kingspan/celotex - membrane - plasterboard).
> > Clearly, the kingspan sits between tanalised studwork that is
> > protected from damp from the wall by a strip of dpc and/or spacers.
>
> No. The kingspan sit BEHIND the studwork. The design is wall-
> kingspan-battens-plasterboard.
>
>
> The problem with insulation *between* studwork is that heat flows
> through the studwork.
>
> A system with 9" brick, 70mm PIR foam, 25mm battens, and 12mm
> plasterboard/MDF/plywood should get you to current regs.
>
> > So, the questions that arise are mostly born of a paranoia about damp
> > from the wall in the longer term:
>
> Nearly all the damp in a wall comes from the *inside*. This seems
> counter-intuitive (it's dry inside and wet outside), but the point is
> that "warm and fairly dry" air contains more water that "cool and
> damp" air. When your steamy kitchen air passes through the
> insulation, the steam will condense and cause damp.
>
> The solution is to be careful about the vapour control layer. The
> insulation will have a foil layer (which should be on the inside), you
> carefully seal this with tape ... and all should be well.
the battens: Why not stick the PB to the celotex and save the depth
of the battens? Whatever the reason, it's hardly practical in a
kitchen where dirty great heavy wall cabinets full of stuff need to be
hung. Screwing a cabinet through PB into studding that's well fixed
to a wall would be fine, whereas screwing through PB, batten, celotex
and then (a bit) into a wall would seem to be a recipe for trouble and
not a problem I'd want in a new kitchen. That would be even worse if
the aim was to meet the regs and use 75 or 100 mm celotex.
Clearly timber studs will provide a bit of cold bridging but the aim
here is to make things better within the limits of practicality rather
than doing a perfect job at one level only to generate a whole range
of other problems.
It seems that sealing the whole thing is the key however and I'll make
sure that's done well.
Cheers
GMM
pretty much before anything else, but that won't be DIY or it would
never be finished.
Unfortunately, there's no way I can do anything in the living room: I
wouldn't lose appreciable floor space, but there's no way I'd ruin
original Victorian cornices by adding anything to the thickness of the
wall, so we'll just have to live with the heat loss there, after
dealing with the floor, windows etc.
GMM
wrote:
up and although I could find the celotex calculator, that models the
wall according to their formulae. It would be useful to know the
influence of any given material.
fred
<983e2d2c-52fe-40e2...@i2g2000yqm.googlegroups.com>, GMM
<Han...@dsl.pipex.com> writes
>Unfortunately, there's no way I can do anything in the living room: I
>wouldn't lose appreciable floor space, but there's no way I'd ruin
>original Victorian cornices by adding anything to the thickness of the
>wall, so we'll just have to live with the heat loss there, after
>dealing with the floor, windows etc.
Older plaster will likely be an inch or so thick so if you remove this
you can fit 25mm insulation backed plasterboard, screwed though into the
brick to gain a bit of insulation.
To avoid damage to the cornice you can isolate it completely by cutting
a groove just under it all the way down to the brick.
There's often a plain step out at the first part of the cornice so if
you are prepared to lose a bit of that feature then you can fit a
thicker insulation board.
Is your plaster straight onto external wall? Here it is straight onto
internal brick walls but is gapped lath and plaster on external walls so
there is more thickness to play with.
--
fred
FIVE TV's superbright logo - not the DOG's, it's bollocks
The Natural Philosopher
about ten in terms of U value.
Celotex is about 0.02 k value.So 100mm of that is about 0.2 U value.
It's in my building regs bookiewookie.
a typical outside hardwood door is about 3-5 so better than 4" of brick..
Robin
> airgap. See here:
>
>
>
Celotex both advise an airgap but in different places. As in that link
Celotex have:
wall+insulation+battens-with-airgap-plasterboard
But Kingspan seem to favour:
wall+battens-with-airgap+insulation+plasterboard
I've not got the faintest idea why (but being cynical I wondered if
Kingspan are trying to push their combined insulation-and-plasterboard
products.)
--
Robin
PM may be sent to rbw0{at}hotmail{dot}com
harry
I have lots of rigid foam insulation. It is in fact virtually
impossible to just cut it to a good fit between battens but vitally
neccesary that it is a perfect fit.
I cut my foam an inch too small and filled the gaps with canned foam.
Cheapest I found is "Screwfix" BTW.
If you don't need fixing/battens, you can secure full sheets of foam
to the wall with the canned foam.. You can get foamed sheet that has a
rough plastic finish that can be plastered instead of the normal foil
finsh. (Don't forget the scrim on the loints.)
BTW,You can get this stuff as seconds about half price, there will be
a place near you. It has voids and mechanical damages but easy fixed
with the canned foam. You order a truck/van loadby phone usually.
Save a lot of dosh.
http://uk.ask.com/web?qsrc=1&o=0&l=dir&q=insulation+seconds&dm=ctry
GMM
> In article
> <983e2d2c-52fe-40e2-ac95-50cc88e79...@i2g2000yqm.googlegroups.com>, GMM
I shall have to investigate that a bit once I actually move and I'm
free to poke about with the place. It would be good if I could do
something with the walls at each end (both ends are outside walls) and
I have to do quite a lot of work in that room anyway so a bit more
mess won't matter, if I can fit things.
stuart noble
> I improved condensation on a solid brick kitchen with 3mm CORK TILES.
>
> That's how little you need to make a difference.
I lined my son's bedroom in cork 30 years ago. Nice big noticeboard
>
> celotex is 50 times better an insulator than brick.
>
> So you can halve U values with just 1/50th the depth of the brick wall.
> If that's 9", that's about 5mm or less
Hmm, that is very interesting.
stuart noble
> impossible to just cut it to a good fit between battens but vitally
> neccesary that it is a perfect fit.
> I cut my foam an inch too small and filled the gaps with canned foam.
Run a panel saw against the batten while cutting through the foam.
Perfect fit every time
d...@gglz.com
If the OP knows where he wants to hang cabinets, it would be possible
to apply celotex-backed plasterboard directly to the outer walls, and
have 100mm square cut outs to accommodate timber "pads" fixed to the
masonry, to provide secure cabinet mountings - with scarcely any
impact on overall insulation values.
Jim K
Yup I have done exactly that here (for floating shelves for e.g.) also
in my latest showerroom for mounting shower valve, screen, bog, basin
etc etc
I lined it all out with the insualted pb first, then measured up and
"cut in" with a jigsaw to create the "pockets" into which some handy
bits of oak were fixed to the masonry with long frame fixers +/-
squirty foam when the fit of wood into pocket was not brilliant.
Jim K
GMM
rooms. Expensive looking but much simpler to fit so swings and
roundabouts. In bedrooms and bathrooms for example, the trick is to
keep the benefit in insulation balanced with the amount of space
sacrificed and there's less of an issue with hanging cabinets etc,
although the idea of hacking a bit out after fitting and installing
something to screw into hadn't occurred to me before.