Damp problems again!!!
Martin
More damp questions - apologies for boring anyone.
The background - my living room has damp problems mainly on two walls
- it rises up to within a foot of the coving. 1870s house solid walls.
I've done all the usual checks. It's not condensation and there is
evidence it's been a problem before. Ground level is below both the
slate dpc and the silicon DPC. Room 25ft by 10ft.
Recently had a quote by a damp company (~Ł3K) to do the following;
- Inject DPC (already has a silicon one and a slate one)
- Strip plaster on two walls (total 35ft inc 3 windows and
frenchdoors)
- Treat the two walls with some sort of waterproofing "stuff"
- Replaster two walls
- Remove bottom 6" of external render and rerender with bellcast.
- Repoint two courses of bricks (35ft) below the DPC.
My plan is to get them to do the DPC (and wall treatment???) and I'll
do the rest. I appreciate the injected DPCs are not trusted by many
but I want to give this work every chance of fixing the problem.
For the internal walls;
- Should I plaster or use plasterboard with a skim? Damp Company
didn't like the idea of plasterboarding as it causes problem with the
wall treatment.
- If I plaster, what type(s) of plaster should I use? I would get
someone in to do this.
- If I plasterboard it presumably celotex could be used to aid
insulation?
- Could I "dot 'n dab" plasterboard direct to the wall?
- Should I treat the bare brick in any way prior to this?
- Do I need to give the walls time to dry out?
- If so roughly how long?
For the external walls;
-What mix of render?
-Any tips with the bellcast beading? How far above the DPCs should it
be?
-What mix for repointing below the DPC?
-What mix for repointing above the DPC?
Incidentally, I am getting a few more quotes!!
All experiences/advice welcome...
Cheers,
Martin.
Mike
"Martin" <mbr...@geocities.com> wrote in message
news:245c3c3e.05040...@posting.google.com...
> Hi All,
>
> More damp questions - apologies for boring anyone.
>
> The background - my living room has damp problems mainly on two walls
> - it rises up to within a foot of the coving. 1870s house solid walls.
> I've done all the usual checks. It's not condensation and there is
> evidence it's been a problem before. Ground level is below both the
> slate dpc and the silicon DPC. Room 25ft by 10ft.
>
> Recently had a quote by a damp company (~Ł3K) to do the following;
>
> - Inject DPC (already has a silicon one and a slate one)
If it has a slate DPC (which usually works or can be made to work) why does
it need an injected one (which doesn't) ?
Jeff
am i right in believing that this is more or less floor to ceiling ?
I was always led to believe that rising damp gets about 2 foot up the wall
and hacking off to a metre high is the done thing.
I would suspect penetrating damp more than rising - are both walls exterior
and rendered ?
Regards Jeff
Andrew Gabriel
mbr...@geocities.com (Martin) writes:
> Hi All,
>
> More damp questions - apologies for boring anyone.
>
> The background - my living room has damp problems mainly on two walls
> - it rises up to within a foot of the coving. 1870s house solid walls.
> I've done all the usual checks. It's not condensation and there is
By what means have you deduced it's not condensation?
Damp up near the ceiling is either condensation or penetrating damp.
> evidence it's been a problem before. Ground level is below both the
> slate dpc and the silicon DPC. Room 25ft by 10ft.
>
> Recently had a quote by a damp company (~Ł3K) to do the following;
You have to accurately identify the cause of the damp before
thinking of ways to fix it. If you've done that, you haven't
said here, and it's necessary to know before advising how to
fix it and how to replaster afterwards.
> My plan is to get them to do the DPC (and wall treatment???) and I'll
> do the rest. I appreciate the injected DPCs are not trusted by many
> but I want to give this work every chance of fixing the problem.
That starts by correctly identifying the cause.
--
Andrew Gabriel
Richard Faulkner
<mbr...@geocities.com> writes
>The background - my living room has damp problems mainly on two walls -
>it rises up to within a foot of the coving.
If your wall is damp above about 3ft, IT IS NOT RISING DAMP, and a DPC
has nothing to do with it.
> 1870s house solid walls. I've done all the usual checks. It's not
>condensation and there is evidence it's been a problem before. Ground
>level is below both the slate dpc and the silicon DPC. Room 25ft by
>10ft.
>
>Recently had a quote by a damp company (~Ł3K) to do the following;
>
>- Inject DPC (already has a silicon one and a slate one) - Strip
>plaster on two walls (total 35ft inc 3 windows and frenchdoors) -
>Treat the two walls with some sort of waterproofing "stuff" - Replaster
>two walls - Remove bottom 6" of external render and rerender with
>bellcast. - Repoint two courses of bricks (35ft) below the DPC.
They obviously dont know what they are doing and are relying on your
ignorance to RIP YOU OFF!!!
The damp could be falling from within a foot of the coving, which
suggests that it is coming from above. It could be Gutters, Overflow
Pipe, Rotten Window, Shower/Sink/Bath/Central Heating etc. Leaking, and
so on - but it is not rising damp!!!
Unless your covings are only 4 ft from the floor/ground level.
--
Richard Faulkner
Chris Bacon
> The background - my living room has damp problems mainly on two walls
> - it rises up to within a foot of the coving. 1870s house solid walls.
> I've done all the usual checks. It's not condensation and there is
> evidence it's been a problem before.
Check your rendering. Check it again. Look for cracks, tap it to see
whether it sounds hollow. See if there are cracks around cills where
water could be getting in. Is the render painted? I've had a few
similar problems in the past.
andre...@tesco.net
Chris Bacon wrote:
> Martin wrote:
> > The background - my living room has damp problems mainly on two
walls
> > - it rises up to within a foot of the coving. 1870s house solid
walls.
> > I've done all the usual checks. It's not condensation and there is
> > evidence it's been a problem before.
>
The age of your house suggests that it has solid 9'' walls, was the
outside rendered to try to cure the problem ? does the damp worsen
after bad weather? old or blocked guttering may be overflowing on to
the wall side and getting behind the render, we had a simmilar problem
with water getting behind paint, once the paint was stripped away there
was a damp patch of about 8 square meters on the outside wall, its just
about dried out now ,about 7 months later
Pete C
Hi,
A few q's, what sort of % humidity do you get inside at room
temperatures? Is the render bridging the DPC? Is the render made from
a breathable mortar, and is it painted? What sort of windows and
heating is there? Did the damp company suggest taking samples from the
wall and having them analysed for salts?
Why not put in a dehumidifier with a humidistat to gain some time
while you investigate the whole thing more fully? Just about
everything you need to know is in the archives of this group and the
forums at 'Period Property'
Bear in mind in the old days the fireplace and draughty windows would
keep the place nice and dry.
cheers,
Pete.
Dave Plowman (News)
> The background - my living room has damp problems mainly on two walls
> - it rises up to within a foot of the coving. 1870s house solid walls.
> I've done all the usual checks. It's not condensation and there is
> evidence it's been a problem before. Ground level is below both the
> slate dpc and the silicon DPC. Room 25ft by 10ft.
I assume this is a brick built house? If so, the very first thing to do is
to check the pointing. And not just visually - for a long way round the
effected area 'tap' it to see if it's loose. And I'll bet you'll find
problems. Rake out and replace using a lime mortar. Don't be tempted to
use a more common sand and cement mix - this will simply crack due to
movement.
Of course, also check for things like failed gutters allowing the wall to
get soaked.
Also, on an old house built in this way, if you've removed and sealed up
all the fireplaces, and fitted double glazing, without adequate
ventilation, and don't keep it warm, you'll get condensation.
--
*I am a nobody, and nobody is perfect; therefore I am perfect*
Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.
Chris Bacon
> - If I plaster, what type(s) of plaster should I use? I would get
> someone in to do this.
Don't use gypsum plaster on anything that's likely to get damp,
incidentally. It will not last.
Martin
Hi All,
Good replies and questions as usual. Apologies for this long reply!
Contrary to one reply I don't regard myself as ignorant!!
Here is what has been tried.....(deep breath)
- Render is good. No cracks and painted. No knowing if it was applied
to try and cure the damp. The only problem I can see with the render
is that it has no bellcast on the bottom. I've no experience of
bellcasts but it makes sense to me.
-Gutter is good. Works with no blockages or leaks.
-No damp in the room immediately above the affected area. Recently
took it back to plaster and it was bone dry.
-The only source of water above the affected area are some central
heating pipes. I've had all the floorboards up and there is no
evidence of previous leaks or current leaks. It's all dusty dry.
-No water tanks or pipes in the loft.
-No water pipes in the walls.
-Damp has been a problem for some time. Replaced with double-glazing
approx one year ago. This has had no effect whatsoever. I've sealed it
up very throughly. No evidence of damp immediately around window when
I removed the old unit. Sash windows must have been fitted originally.
The gaps where the weight boxes would have been have been replced with
timber. These were bone dry and had no evidence of water damage.
-I've tried the old mirror trick and no condensate formed on the
mirror.
-When I replaced the window some of the least accesible brickwork was
noticeably damp.
-The metal inserts used to get a good corner on the plaster and a
couple of socket back boxes are rusting as well which indicates to me
that it's not condensation.
-I was told the same thing about rising damp being only able to get a
few feet up the wall but it doesn't change the fact I have damp to
approx 8ft.
-One builder and two damp companies have agreed the exterior render
(painted by the way) is in good order.
-Wall are solid 9" with no cavaties. It used to be a commercial
property but was converted to residential in 1988.
-Someone feel free to correct me, but I heard that slate dpcs fail
after a time. This one is 135+ years old so I'm not expecting it to be
that good.
-Both walls are exterior and rendered.
-Weather doesn't seem to affect the levels of damp - I experimented
over the summer.
-There is some paint bubbling on the outside when it rains (approx the
size of a dinner plate) but this approx 10ft from the worst affected
area. The rest of the paint seems to be stuck fast as is the render.
So the question remains (one I've been trying to answer for some time)
is it rising or penetrating damp. I see no way it could penetrate the
walls so it has to be rising damp? The only weird thing is it's almost
up to the ceiling.
I do have another couple of damp companies coming around to give me a
quote - it's going to be interesting to hear what they advise.
Any advice suggestions would be most appreciated. Someone did suggest
moving but that's not really possible at the moment!
Any experience of bellcasts on the render solving problems would be
good to hear. It does sound logical that rain hits the wall, runs down
and soaks in immediately above the silicon (and slate) dpc. A bellcast
would prevent this and theoretically involve only a small outlay of
time and expense to try.
Cheers,
Martin.
Richard Faulkner
>quote - it's going to be interesting to hear what they advise.
Make sure that they are members of the BWPDA, (www.bwpda.co.uk).
Ask them how damp could rise above 3 ft, when all theory says it cant.
It may be worth paying for someone to take a core sample from the
brickwork to see if it is damp in the wall, and not just on the surface.
Many damp companies dont know what they are doing, and tell you
something needs doing when it doesnt.
Are you anywhere near Manchester?
--
Richard Faulkner
andre...@tesco.net
Martin wrote:
> andre...@tesco.net wrote in message
news:<1112797060.3...@z14g2000cwz.googlegroups.com>...
> > Chris Bacon wrote:
> > > Martin wrote
> size of a dinner plate) but this approx 10ft from the worst affected
> area. The rest of the paint seems to be stuck fast as is the render
>
on our wall there were a few patches of bubbling paint the majority of
it looked fine, once removed though the wall was damp over a large area
which had been covered in 'good' paint. one of the problems was the
previous owners had used a rubber based paint half way up the wall (to
cure the damp) so the water couldn't evaporate once it had got behind
the paint, as someone said earlier any paint used should be breathable.
Could you scrape a patch of the bubbling paint away to see if the
render is damp underneath any water can travel a fair distance before
it finds its way in.
nafuk
Check pointing
Is the floor dirt - my 1850s semi had carpet on tiles on sand/earth.
so even though outside ground level was below the dpc the walls were
still damp - this construction is ok but it's not designed to have
carpet etc. on it, only bare tiles so that moisture can evaporate.
Check ventilation of chimney etc. - are you drying washing inside?
Has the house been unoccupied?
I put in a small French drain - dug down about 9-12" on outside walls,
and about 9" away from walls, and filled the trench with pea shingle,
and put old slate floor tiles as a border - looks good.
Whilst doing the French drain I also repaired the pointing
underground, which was very bad around the bay window (lots of
movement that made cracks and the lime mortar had fallen out), and
cleaned all the caked on clay from the bricks (which may assist the
wicking-up of water into the walls).
Can't defiantely say but I think the French drain did quite a lot - it
now means that damp wpould have to travel up an extra 12" before it
gets inside.
I also replaced the floor with an insulated dpc protected concrete
floor - diy it and it's quite cheap, and a good workout.
There is a side which says that rising damp is not a real problem and
damp companies do nothing and are a waste of time. If you want to go
down this route you can rent the solutions and pumps, drills etc.
quite cheaply and do the whole thing in a weekend for about £100-150
(if you do this do rent/buy a good SDS drill and have a spare 10 mm
bit).
I'd try the simple things first pointing (above and below ground),
French drain, ventilation, put heating on, open a window when drying
washing etc.
Good luck
Martin
Hi All,
Apologies for the lack of reply. Computer packed up but at least that
was cheap DIY fix!!
Affected wall is painted and rendered. Below the silicon injections,
the render does need repair. Still don't know if it's rising damp or
penetrating damp.
Floor is good with the correct membrane.
There is also a draining channel against the wall - half full of
shingle.
At the moment, I'm getting quite cheesed off with this damp problem.
Another company have just paid me a visit. Their recommendation is to
tank the walls at a cost of £4k+.
Now I'm really unsure of what to do. £4K+ seems *cough* excessive. DIY
tanking?? The company's attitude was that on damp solid walls only
tanking would fix it. So I assume he believes it's penetrating damp.
However, he then went on about the temperature difference being
greater which implies condensation so why should it need tanking?
Hmmm...
A few answers to previous questions...
Q: Is the house occupied?
A: Yep. For 15+ years
Q: Are the gutters ok?
A: Perfect. No leaks, no overflowing. They work fine.
Q: Old house now sealed up causing condensation?
A: Condensation is definetly not the issue. I ran a dehumidifer for 6
months+ and it made no difference. Plaster was still coming off the
wall.
Q: What sort of % humidity?
A: No idea. Dehumidifer was running and walls were still damp. I don't
do anything daft liking drying washing in the house.
Q: Check ventilation?
A: No obvious ventilation but dehumidifer made no diffence. Solid
floor, no air bricks, no vents, no chimney. Strange for a house that
used to be a Bakery but I've found no evidence of where a chimney used
to be.
Any other suggestions? DIY tanking?
I've another company paying me a visit on Monday - anyone care to take
bets on their being a third different solution to the same problem?
Cheers,
Martin.
andre...@tesco.net
> Any other suggestions? DIY tanking?
> I've another company paying me a visit on Monday - anyone care to
take
> bets on their being a third different solution to the same problem?
The best advice i received when we had our problems was from a painter
and decorator, it was a medium sized company, the Boss came round,no
reps, he said he sees it all the time, what did impress me was he didnt
view it as a 'problem' it was just his job
markzoom
If the outside finish is waterproof (as opposed to water-repellant)
then your walls can't dry from the outside. All they will eternally do
is soak up moisture from the inside air by condensation, particularly
if they are single thickness and always colder than the inside. How
about stripping any waterproofing from the outside and relacing it
with breathable water-repellant.
M.K.
Anna Kettle
Like others I've had success with French drains. You could also make
the inside of the wall breathable so the damp can evaporate into the
room. Of course there is a limit to how much water can evaporate and
if you have a stream erupting onto the wall, breathability is not
going to help, though a French drain would
Breathability - remove gypsum plaster, cement render and modern paints
from the inside of the ?bricks?. Do not add any tanking, PVA etc.
Replaster with lime plaster and paint with limewash. It can't do any
harm, is cheap if you do it yourself and might do a lot of good
Anna
~~ Anna Kettle, Suffolk, England
|""""| ~ Lime plaster repairs
/ ^^ \ // Freehand modelling in lime: overmantels, pargeting etc
|____| www.kettlenet.co.uk 01359 230642
Jeff
Martin wrote :-
> Affected wall is painted and rendered. Below the silicon injections,
> the render does need repair. Still don't know if it's rising damp or
> penetrating damp.
If the render extends below the dampproof membrane then it is bridging the
membrane - it needs removing to above the membrane
chemical injection is one thing but you also have to take care of the
obvious ie make sure nothing can bridge the new DPC outside or inside - I
had to remove render outside and have 7" skirting inside
> There is also a draining channel against the wall - half full of
> shingle.
What exactly is this ?
Regards Jeff
Pete C
>A few answers to previous questions...
>
>Q: Old house now sealed up causing condensation?
>A: Condensation is definetly not the issue. I ran a dehumidifer for 6
>months+ and it made no difference. Plaster was still coming off the
>wall.
>
>Q: What sort of % humidity?
>A: No idea. Dehumidifer was running and walls were still damp. I don't
>do anything daft liking drying washing in the house.
Hi,
What sort of heating arrangements do you have? Eg how long is the room
heated per day and to what temperature.
Also what sort of windows do you have? Eg double glazed or draughty
sash etc
And does the render bridge the slate DPC in any way?
A dehumidifier won't necessarily remove the damp under any
circumstances but it should at least contain the problem to some
extent while it's investigated.
>Any other suggestions? DIY tanking?
>I've another company paying me a visit on Monday - anyone care to take
>bets on their being a third different solution to the same problem?
AFAIK one of the best ways of diagnosing damp is to send samples of
the wall away for chemical analysis for hygroscopic salts.
Dry lining the wall might be another way forward.
cheers,
Pete.
jim_in_sussex
As other posters are saying, this just doesn't sound like rising damp.
However if you do decide to chase the rising damp idea, avoid wet
injection pressurised damp proof injection systems. These work by
injecting a water diluted silicone (or similar chemical) into the wall
& then you have to wait for the old water PLUS the new water to dry
out before you (might) have a dry wall.
A better alternative is Dryzone Cream made by Safeguard Chemicals of
Horsham. It changes the chemical nature of the mortar bewteen the
bricks rendering it waterproof & there is no new water going into the
wall. You still have to drill 12mm holes into the wall every 100mm,
as in the wet systems, but you drill into the mortar which is easier.
Then you squeeze the cream into the holes by a special applicator gun
- low pressure, no messy spills.
Mike
> Affected wall is painted and rendered. Below the silicon injections,
> the render does need repair. Still don't know if it's rising damp or
> penetrating damp.
>
> Floor is good with the correct membrane.
>
> There is also a draining channel against the wall - half full of
> shingle.
So which side of the membrane is this ?
Also how old is the house ? Should there be a membrane at all ? In very
old houses in a damp location you need the whole floor area to evaporate the
moisture. It may be this membrane is pushing all the damp into the walls
until they are saturated amd things start to fail.
> At the moment, I'm getting quite cheesed off with this damp problem.
Where are you ?
> Another company have just paid me a visit. Their recommendation is to
> tank the walls at a cost of £4k+.
Unless it's underground and you've no other way of removing the water I
wouldn't.
Stuart Noble
solvent masonry paint. Johnstones do a a product called Stormguard, and
most
trade paint companies have equivalent brands. These are *vastly* superior
to
normal masonry paints and aren't that expensive. That should at least
eliminate penetrating damp as the cause.
Stone sills are also a major source of damp, however sound they look.
Water
often sits in puddles, and has time to soak into the brickwork and travel
through the mortar.
In a brick built house rising damp is probably the least likely source.
--
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The Natural Philosopher
Ho w about opening a fucking wibdow or fitting stautory ventilation?
Since is is now mnadatory that hoese have vapour bariers inside them,
yoyr explanbatuoj is bollocks.
Stuart Noble
"The Natural Philosopher" <A@b.c> wrote
> Ho w about opening a fucking wibdow or fitting stautory ventilation?
> Since is is now mnadatory that hoese have vapour bariers inside them,
yoyr
> explanbatuoj is bollocks.
Mike
"The Natural Philosopher" <A@b.c> wrote in message
news:111318798...@dyke.uk.clara.net...
>
> Since is is now mnadatory that hoese have vapour bariers inside them,
> yoyr explanbatuoj is bollocks.
On new houses possibly - though the building regs are at best unclear on
this.
BUT old houses do not need these fitted and indeed fitted wrongly will cause
more harm than good.
big...@meeow.co.uk
This is classic stuff, the damp old Victorian house that goes from bad
to worse despite all the efforts of dampproofing 'specialists'. And the
cause? The fact that all the wrong things are being done. This scenario
plays out over and over again, so often its a well known deal.
Add to this the twin facts that
a) you dont understand how damp is managed in Vic properties, and
b) you've made mistakes in your conlcusions,
and you cant get to the bottom of it either.
First, if you want to understand damp and Vic properties, I'd recommend
a good long chat at
http://www.periodproperty.co.uk/cgi-bin/discussing/forum2.pl?#43991
Now, whats going on:
1. Vic houses handled damp fine when they wre built, they were not pits
of damp. So the basic design is good.
2. Since its damp now, it is what has been changed that has caused it.
What has changed?
1. Airtight double glazing stops ventilation
2. Chimney blocked off
3. Maybe draught proofing elsewhere too
4. Gysum plaster and emulsion
5. Cement render and paint
6. shower installed
All of these increase the damp levels in the walls, and some properties
then begin to fail to deal satisfactorily with the damp.
Contrary to your conclusions, the cause is indeed condensation. Why did
the dehumidifier not cure it? Primarily because it has been going on
for so long that the walls have become soaked, so that it will take
many months to dry them out. Also there are other works that will need
doing to fix it properly, eg the exterior render will be an ongoing
problem.
What else needs doing?
The first thing to understand is you need to allow the wall to dry out,
not trap all that water in it, which is what all your presently
considered works are about.
No to tanking
No to rendering
No to painting with water resistant paints
No to a 3rd DPC (!!) (slate should last much longer than 130 years)
Yes to:
Humidistatic dehumidifier
Lowering ground levels if theyre at or above the dpc
Checking the drain channel drains properly
Repoint all failed mortar with lime - but dont remove anything thats
stuck hard.
Removing all exterior render, and finishing by either cleaning the
bricks up, or if theyre too much of a mess, lime render.
Remove interior plaster and replaster with lime, painting with lime
based paints, not emulsion.
Checking ground water drains away from the house, not to the walls.
And I would add ventilation to the house for your own health, though
this is not necessary re damp until such time as you stop using the
dehumidifier.
Pay attention to major sources of damp within the house:
Install dehumidifier in bathroom, or maybe a fan.
And possibly enclose the shower so it doesnt produce as much steam in
the room, if practical.
And preferably install a cooker hood
Understand some basic concepts with these houses:
1. More damp is produced inside by breathing, cooking and showering
than comes from outside
2. Thus what is wanted is porosity, to allow the damp out, quite the
opposite of sealing.
3. Damp proofing companies do work so they can get your money.
4. If dealt with appropriately, a Vic house with no dpc, no render, no
waterprofing treatments etc can be dry and healthy.
5. Also be aware that a 9" wall will take a very long time to dry out,
even with the above treatments done.
BTW there is one gotcha: the bricks will be very soft, and the cement
render hard, and it is _very_ easy to do serious brick damage when
removing the render. Proceeed only with serious care on this point.
NT
Edgar Iredale
I'd agree with that. It's the conclusion I came to, despite all the advice I
was given by "experts" when I was considering buying a damp Victorian house
a couple of years ago.
There are some additions. Make sure the tumble drier is properly vented and
the filter is clear. Don't dry washing in the house. Open the windows wide
and let the wind blow through the house once a week in addition to normal
good ventilation.
I also think similar things apply to much more recent buildings. I've
experienced these problems in '60s flats and a '50s bungalow. Efforts to
keep rain and weather out cause troublesome build up of condensation. Once
the condensation has built up in the structure it has every appearance of
coming in from outside. It takes months to dry out.
Don't paint outside walls unless it is absolutely necessary, and then use a
paint that won't prevent the wall to dry outwards.
(I'm trying to dry out the insulation in an old freezer at the moment - and
it is taking weeks. Think how much longer a wall will take.)
And don't forget there's little money to be made from giving "ventilate -
don't cause moisture buildup" kind of advice.
Edgar
Stuart Noble
The oracle has spoken!
Your condensation theory is blown away when you consider that most of
these
houses get the same symptoms after a heavy shower in mid summer, when
there
are insufficient cold surfaces to cause condensation, and the windows are
wide open.
The idea that a house should allow the passage of any amount of water
through the walls and wait for it to dry out is Dickensian, and faintly
ridiculous in this day and age. It means houses would effectively be damp
for at least 9 months of the year.
What has changed to make Victorian properties leak like a sieve, when
presumably they didn't originally, is IMO the degradation of the lime
mortar. If that powder between the bricks in a 9" wall is all that's
protecting you from the elements, then you need look no further. Replacing
it with mud would be an improvement.
big...@meeow.co.uk
> Your condensation theory is blown away when you consider that most of
> these
> houses get the same symptoms after a heavy shower in mid summer, when
> there
> are insufficient cold surfaces to cause condensation, and the windows
are
> wide open.
it doesnt blow the theory away at all.
1. I have not observed that to be the case, although of course it will
be in some properties
2. A summer shower sends the RH up to 100% rapidly, inevitably
increasing the odds of condensation.
3. There are many buildings with penetrating damp problems, which will
fit your above analysis. Many of course have both penetrating damp and
condensation problems.
4. see below about how this can cocur
> The idea that a house should allow the passage of any amount of water
> through the walls and wait for it to dry out is Dickensian,
that may be why 'any amount' wasnt suggested
> and faintly
> ridiculous in this day and age. It means houses would effectively be
damp
> for at least 9 months of the year.
Another classic misconception there. As air exchanges between a warm
house and cold exterior, 2 things occur.
1. Cold damp air comes into the house and is warmed. Since warm air can
carry much more moisture than cold, its RH drops considerably as it is
warmed.
2. Warm air that feels dry is carried outside. Warm air can hold lots
more moisture, and as it cools outside it becomes damp air.
The heat differential plus ventilation results in drying of the
interior, even during wet winter months. It is only on wet summer days
that ventilation does not produce this drying effect, since incoming
and outgoing air are at apx the same temp. And in any place where its
cooler inside than out at the time, which is not unusual, with RH at
100% outdoors, condensation is liable to happen.
> What has changed to make Victorian properties leak like a sieve, when
> presumably they didn't originally,
originally they had:
open chimneys, which accept the 56" of rain per year we get
draughty sash windows
draughty doors
no wall dpc in most cases
no floor dpc in most cases
porous bricks and lime mortar
and unsarked slate roofs, which allow some rain in too.
> is IMO the degradation of the lime
> mortar. If that powder between the bricks in a 9" wall is all that's
> protecting you from the elements, then you need look no further.
Replacing
> it with mud would be an improvement.
Mud soaks up water, so that wouldnt help. Mud also has a much lower
compressive strength in newtons per square metre, so would make the
walls unstable. Wet mud has very poor compressive strength, rather than
being an improvement it would be dangerous.
Mortar in poor condition can as you say cause penetrating damp, and
this is a problem on some old properties. The solution is to repoint in
lime, because lime helps the wall dry out after the rain. Vic house
walls are not normally waterproof, rain soaks in, they rely rather on
the rain then evaporating away again quickly enough afterwards to avoid
rain penetration.
NT
Stuart Noble
> 2. A summer shower sends the RH up to 100% rapidly, inevitably
> increasing the odds of condensation.
Let's just say I've never noticed condensation in summer. Not in the
bathroom, or on the windows, or anywhere else I expect it in winter.
>> The idea that a house should allow the passage of any amount of water
>> through the walls and wait for it to dry out is Dickensian,
>
> that may be why 'any amount' wasnt suggested
So your beloved lime is self regulating is it? When we get driving rain
for
days on end, it stops absorbing water at a certain point does it?
> Mortar in poor condition can as you say cause penetrating damp, and
> this is a problem on some old properties. The solution is to repoint in
> lime, because lime helps the wall dry out after the rain.
>Vic house
> walls are not normally waterproof, rain soaks in, they rely rather on
> the rain then evaporating away again quickly enough afterwards to avoid
> rain penetration.
I'm sure lime is fine in the right sort of thick walled country residence
but not as a general repair mortar for 9" brickwork in terraced houses.
Use
a pozzolan? Well then you might as well use cement.
Dave Plowman (News)
Stuart Noble <stuart_no...@ntlworld.com> wrote:
> > 2. A summer shower sends the RH up to 100% rapidly, inevitably
> > increasing the odds of condensation.
> Let's just say I've never noticed condensation in summer. Not in the
> bathroom, or on the windows, or anywhere else I expect it in winter.
Then the chances are you're not heating and ventilating the house properly
in the winter.
If you choose to try and save money in an old house by blocking up
ventilation to try and save on heating bills - and don't keep the temp up
- you'll get damp. Best to change to a cheaper well insulated modern house
designed to work like this - and just put up with the lack of space.
--
*Where there's a will, I want to be in it.
big...@meeow.co.uk
> > 2. A summer shower sends the RH up to 100% rapidly, inevitably
> > increasing the odds of condensation.
>
> Let's just say I've never noticed condensation in summer. Not in the
> bathroom, or on the windows, or anywhere else I expect it in winter.
good.
> >> The idea that a house should allow the passage of any amount of
water
> >> through the walls and wait for it to dry out is Dickensian,
> >
> > that may be why 'any amount' wasnt suggested
>
> So your beloved lime is self regulating is it?
what are you talking about?
> When we get driving rain
> for
> days on end, it stops absorbing water at a certain point does it?
kind of hard to go past saturation I'd say. But maybe you know a way.
The water doesnt flow from outside to inside quickly, so the inner wall
face doesnt get wet because of it. Victorians sometimes used cavity
wall construction to reduce penetrating damp in cases where heavy
driving rain was expected. They were not introduced for insulation.
> > Mortar in poor condition can as you say cause penetrating damp, and
> > this is a problem on some old properties. The solution is to
repoint in
> > lime, because lime helps the wall dry out after the rain.
> >Vic house
> > walls are not normally waterproof, rain soaks in, they rely rather
on
> > the rain then evaporating away again quickly enough afterwards to
avoid
> > rain penetration.
>
> I'm sure lime is fine in the right sort of thick walled country
residence
> but not as a general repair mortar for 9" brickwork in terraced
houses.
Its already clear you dont know much about the subject.
The vast majority of Victorian terraces wre built with lime mortar, its
success is well and truly beyond doubt.
> Use
> a pozzolan? Well then you might as well use cement.
Clearly this is a waste of time.
NT
Stuart Noble
>> I'm sure lime is fine in the right sort of thick walled country
> residence
>> but not as a general repair mortar for 9" brickwork in terraced
> houses.
>
> Its already clear you dont know much about the subject.
Does 30 odd years of practical experience count?
> The vast majority of Victorian terraces wre built with lime mortar, its
> success is well and truly beyond doubt.
As the extensive use of render and pebbledash will testify. Do you think
they put that stuff on for aesthetic reasons?
No, hold on, I've got it. It's because they're all stupid, right?
>> Use
>> a pozzolan? Well then you might as well use cement.
>
> Clearly this is a waste of time.
It is a waste of time if you don't put forward a valid argument. Lime
mortar
in the sort of quantities you would use for re-pointing will not stay put
and will not resist heavy rain without some kind of setting. A pozzolan
will
provide this but even the staunchest, Morris dancing, lime lover will
admit
that it negates the benefits of lime. Perhaps you can enlighten us as to
how
these problems are overcome in the real world.
Andrew Gabriel
>>> but not as a general repair mortar for 9" brickwork in terraced houses.
>>
>> Its already clear you dont know much about the subject.
>
> Does 30 odd years of practical experience count?
>
>> The vast majority of Victorian terraces wre built with lime mortar, its
>> success is well and truly beyond doubt.
Some (but by no means all) victorian houses did use a little
cement in the lime pointing (which is just the outer 1/4").
> As the extensive use of render and pebbledash will testify. Do you think
> they put that stuff on for aesthetic reasons?
Yes -- they didn't like the look of commons. Depending on the area,
some part of the house (often the front, but it varies from nothing
through to all the external walls) would use something more expensive.
Mine is not untypical -- there are no commons visible from the front.
The ground floor uses (what were) expensive facing bricks, but these
are very soft and are somewhat protected from the weather by a canopy
roof which runs the length of the terrace, forming extended porches and
ground floor bay window roofs. There is a 12" render skirt to protect
the soft bricks from ground splash. The first floor front is a mixture
of pebbledash with rendered highlights around windows, corners, etc.
(Pebbledash at ground level was not considered good because of what
happens when you walk into it.) The side and rear external walls are
all commons, no render/pebbledash/skirts.
> It is a waste of time if you don't put forward a valid argument. Lime mortar
> in the sort of quantities you would use for re-pointing will not stay put
> and will not resist heavy rain without some kind of setting. A pozzolan will
> provide this but even the staunchest, Morris dancing, lime lover will admit
> that it negates the benefits of lime. Perhaps you can enlighten us as to how
> these problems are overcome in the real world.
Neither will cement mortar. Like cement based mortar, you keep it
covered until it sets if there's a danger of rain. It just takes longer.
--
Andrew Gabriel
Pete C
<stuart_no...@ntlworld.com> wrote:
>
>>> I'm sure lime is fine in the right sort of thick walled country
>> residence
>>> but not as a general repair mortar for 9" brickwork in terraced
>> houses.
>>
>> Its already clear you dont know much about the subject.
>
>Does 30 odd years of practical experience count?
30 years experience of what? Eg 30 years as an architect or a brickie
doesn't make you a structural engineer.
>> The vast majority of Victorian terraces wre built with lime mortar, its
>> success is well and truly beyond doubt.
>
>As the extensive use of render and pebbledash will testify. Do you think
>they put that stuff on for aesthetic reasons?
>No, hold on, I've got it. It's because they're all stupid, right?
Yes they are (or were) really stupid in a lot of cases, it was done
because pebbledash was considered the 'in thing' by some people at the
time. and they wanted their vic terrace to look 'modern' and different
to the others in their street..
Adding a vapour barrier to a wall or reducing it's vapour permeability
without understanding where humdity is coming from or going to, can
introduce or compound damp problems instead of solve them in a lot of
cases.
cheers,
Pete.
Dave Plowman (News)
Stuart Noble <stuart_no...@ntlworld.com> wrote:
> > The vast majority of Victorian terraces wre built with lime mortar, its
> > success is well and truly beyond doubt.
> As the extensive use of render and pebbledash will testify. Do you think
> they put that stuff on for aesthetic reasons?
Mainly yes. To make their house look different from next door.
> No, hold on, I've got it. It's because they're all stupid, right?
They certainly are - it reduces the value of the property.
--
*Don't worry; it only seems kinky the first time.*
Stuart Noble
"> Yes they are (or were) really stupid in a lot of cases, it was done
> because pebbledash was considered the 'in thing' by some people at the
> time. and they wanted their vic terrace to look 'modern' and different
> to the others in their street.
There's usually a practical basis for fashions in building, and it's
difficult to think of anything that is so hard wearing and waterproof. Had
they known about pva when most of it was done, it probably wouldn't have
cracked the way it has.
> Adding a vapour barrier to a wall or reducing it's vapour permeability
> without understanding where humdity is coming from or going to, can
> introduce or compound damp problems instead of solve them in a lot of
> cases.
Pebbledash is hardly a vapour barrier. The idea is to resist water
droplets.
Vapour is air, and nothing short of a sheet of plastic will stop, or
significantly reduce, that.
Pete C
<stuart_no...@ntlworld.com> wrote:
>
>"> Yes they are (or were) really stupid in a lot of cases, it was done
>> because pebbledash was considered the 'in thing' by some people at the
>> time. and they wanted their vic terrace to look 'modern' and different
>> to the others in their street.
>
>There's usually a practical basis for fashions in building,
Does this also include 'Tudorbethan' houses and stone cladding (aka
'crazy' paving)?
>and it's
>difficult to think of anything that is so hard wearing and waterproof.
Or good at creating interstitial condensation if it cracks away from
the wall, or retaining damp while it's wet.
>Had
>they known about pva when most of it was done, it probably wouldn't have
>cracked the way it has.
The properties of lime cement and portland cement have been known for
a long long time.
>> Adding a vapour barrier to a wall or reducing it's vapour permeability
>> without understanding where humdity is coming from or going to, can
>> introduce or compound damp problems instead of solve them in a lot of
>> cases.
>
>Pebbledash is hardly a vapour barrier. The idea is to resist water
>droplets.
>Vapour is air, and nothing short of a sheet of plastic will stop, or
>significantly reduce, that.
Hmmm:
Why hard portland cement and pebbledash should not be used on
traditional stone buildings:
<http://www.northwales.org.uk/jn/whynot.htm>
Grant funded envelope schemes involving public buildings (and problems
thereof):
<http://www.northwales.org.uk/jn/envelope.htm>
Pebbledashed exterior ruins dream period property:
(also How do I remove stone cladding and then finish the walls)
<http://www.periodproperty.co.uk/uncle062004.shtml>
Removing Pebbledash to Solve Dampness:
<http://www.periodproperty.co.uk/uncle012002a.shtml>
I'd still be interested to know where your 30 odd years of experience
lie...
cheers,
Pete.
Andrew Gabriel
Pete C <pete...@gmail.com> writes:
> The properties of lime cement and portland cement have been known for
> a long long time.
Well, for lime and natural cement, at least a couple of thousand
years. Portland cement was new in Victorian times, and too expensive
to use as a general purpose building cement in houses until sometime
around 1920.
--
Andrew Gabriel
big...@meeow.co.uk
>>> I'm sure lime is fine in the right sort of thick walled country
residence
>>> but not as a general repair mortar for 9" brickwork in terraced
houses.
>> Its already clear you dont know much about the subject.
>Does 30 odd years of practical experience count?
It does, but it doesnt guarantee much. It takes time, opportunity, a
fair brain and interest to learn. If you cant work out that the Vics
used lime mortar with great success on 9" terraced house walls, I guess
you must be missing one of the things in that list.
Of course if you have some wonderful insight none of us have, and can
in fact explain why and how millions of Vic houses have actually not
stood the test of time with lime mortar, despite all appearances,
please feel free to educate us.
I think IMM already agrees with you.
>> The vast majority of Victorian terraces wre built with lime mortar,
its
>> success is well and truly beyond doubt.
>As the extensive use of render and pebbledash will testify.
sounds none too logical
> Do you think they put that stuff on for aesthetic reasons?
In a lot of cases, yes. There are plenty of walls built out of
basically mixed junk, and look a right sight when the render is
removed.
Also it was put onto 4" walls to waterproof and help stabilise them, 4"
house walls are not particularly good.
Also of course it was put on for the wrong reasons, just as it
continues to be widely today. Regrettably, a lot of work is done simply
so that the builder can receive payment for it.
> No, hold on, I've got it. It's because they're all stupid, right?
The Victorians were 1 sd lower in iq than we are today, and that is
significant, but otoh there were far fewer subjects for people to go
into, and building attracted much greater levels of talent than it does
today. Looking at those old buildings suggests plenty of skill in their
construction. So if anything, Vic builders were probably just as smart
as today, and maybe more so.
>>> Use
>>> a pozzolan? Well then you might as well use cement.
>> Clearly this is a waste of time.
>It is a waste of time if you don't put forward a valid argument.
Feel free. So far youre given no substance on that point at all. But
maybe best to just concentrate on your claims so far.
> Lime mortar
> in the sort of quantities you would use for re-pointing will not stay
put
> and will not resist heavy rain without some kind of setting.
Well, plenty of people are doing it, and find plastic sheet or sacking
makes it work just fine.
> A pozzolan will
> provide this but even the staunchest, Morris dancing, lime lover
will
> admit that it negates the benefits of lime.
does it
> Perhaps you can enlighten us as to how
>these problems are overcome in the real world.
You would need to start by telling us what you claim these problems
are! I've addressed the first one - the rest you dont even mention.
>> Yes they are (or were) really stupid in a lot of cases, it was done
>> because pebbledash was considered the 'in thing' by some people at
the
>> time. and they wanted their vic terrace to look 'modern' and
different
>> to the others in their street.
> There's usually a practical basis for fashions in building, and it's
> difficult to think of anything that is so hard wearing and
waterproof.
Well, plain brick seems to have done just fine... so it doesnt look
like that was the reason.
> Had
> they known about pva when most of it was done, it probably wouldn't
have
> cracked the way it has.
If you think adding pva stops render cracking on Vic houses, this shows
just how little understanding of the subject you have.
>>> Yes they are (or were) really stupid in a lot of cases, it was done
>>> because pebbledash was considered the 'in thing' by some people at
the
>>> time. and they wanted their vic terrace to look 'modern' and
different
>>> to the others in their street.
>>There's usually a practical basis for fashions in building,
>Does this also include 'Tudorbethan' houses and stone cladding (aka
>'crazy' paving)?
exactly. What is the practical basis for stone cladding Stuart?
The practical basis for it is simple: its a means for builders to take
money off customers. Just like render, and a host of other worthless
jobs we see regularly on houses.
> I'd still be interested to know where your 30 odd years of experience
lie...
indeed. I can think of some possibilities.
NT
Stuart Noble
>>Pebbledash is hardly a vapour barrier. The idea is to resist water
>>droplets.
>>Vapour is air, and nothing short of a sheet of plastic will stop, or
>>significantly reduce, that.
>
> Hmmm:
>
> Why hard portland cement and pebbledash should not be used on
> traditional stone buildings:
>
> <http://www.northwales.org.uk/jn/whynot.htm>
>
> Grant funded envelope schemes involving public buildings (and problems
> thereof):
>
> <http://www.northwales.org.uk/jn/envelope.htm>
>
> Pebbledashed exterior ruins dream period property:
> (also How do I remove stone cladding and then finish the walls)
>
> <http://www.periodproperty.co.uk/uncle062004.shtml>
>
> Removing Pebbledash to Solve Dampness:
>
> <http://www.periodproperty.co.uk/uncle012002a.shtml>
>
>
do?
> I'd still be interested to know where your 30 odd years of experience
> lie...
Well I've owned 2 houses that suffered damp and maintained at least 3
others, so I've been able to monitor things pretty closely over the years.
How about you?
Out of interest, check out the qualities of styrene butadene copolymers in
render mixes.
Dave Plowman (News)
Stuart Noble <stuart_no...@ntlworld.com> wrote:
> > Yes they are (or were) really stupid in a lot of cases, it was done
> > because pebbledash was considered the 'in thing' by some people at the
> > time. and they wanted their vic terrace to look 'modern' and different
> > to the others in their street.
> There's usually a practical basis for fashions in building, and it's
> difficult to think of anything that is so hard wearing and waterproof.
> Had they known about pva when most of it was done, it probably wouldn't
> have cracked the way it has.
Rendering of any sort cracks because of movement in the wall. PVA won't
help this.
--
*Dance like nobody's watching.
Stuart Noble
"Dave Plowman (News)" <da...@davenoise.co.uk> wrote in message
news:4d5b9b2...@davenoise.co.uk...
> In article <8Rr7e.1545$It4....@newsfe2-gui.ntli.net>,
> Stuart Noble <stuart_no...@ntlworld.com> wrote:
>> > Yes they are (or were) really stupid in a lot of cases, it was done
>> > because pebbledash was considered the 'in thing' by some people at
the
>> > time. and they wanted their vic terrace to look 'modern' and
different
>> > to the others in their street.
>
>> There's usually a practical basis for fashions in building, and it's
>> difficult to think of anything that is so hard wearing and waterproof.
>> Had they known about pva when most of it was done, it probably wouldn't
>> have cracked the way it has.
>
> Rendering of any sort cracks because of movement in the wall. PVA won't
> help this.
bonds
effectively in the first place. SBR allows an overall render thickness of
3/8", which wasn't considered possible before. Structural movement is
generally small so it doesn't need to be that flexible to permit movement.
There's also the chicken and egg aspect. Things that get wet swell so, if
you can stop them getting wet in the first place, the movement is likely
to
be less. You can't control movement in the ground below but what you do
above ground helps.
I don't think anyone has the answer to these problems of maintaining
Victorian houses without spoiling their appearance and at the same time
making them fit to live in by today's standards. It doesn't help to adopt
a
brown eggs and bicycles stance and say we'll just use what the Victorians
used. In the case of my current house, what they used was lime with brick
dust, which sets just fine (and how else could you lay bricks with it?)
but,
it seems to me, hydraulic lime gives you the worst of both worlds, the
brittleness of cement without its good properties.
I really would like to hear comments from anybody that's actually used
lime
mortar for re-pointing. Was it hydraulic, how long did it need to be
covered
etc?
Pete C
<stuart_no...@ntlworld.com> wrote:
>Hmm. What kind of response is that? Is quoting web sites the best you can
>do?
What's wrong with that? These days I prefer to learn from others
experience and expertise than by my own mistakes.
>
>> I'd still be interested to know where your 30 odd years of experience
>> lie...
>
>Well I've owned 2 houses that suffered damp and maintained at least 3
>others, so I've been able to monitor things pretty closely over the years.
>How about you?
I've lived in a number of houses. I do have a bit of first hand
experience of wood and rot, damp and dehumdification, steel and
corrosion though...
>Out of interest, check out the qualities of styrene butadene copolymers in
>render mixes.
>
Yes, SBR is an excellent bonding agent and waterproofer. Although
renders based on Pliolite resins based in turn on SBR are often
microporous, I don't think that mixing your own render using an SBR
additive will guarantee it will be microporous. It seems that the
amount of SBR in the render is important to get the best of both
worlds.
cheers,
Pete.
Stuart Noble
"Pete C" <pete...@gmail.com> wrote in message
>>Hmm. What kind of response is that? Is quoting web sites the best you
can
>>do?
>
> What's wrong with that? These days I prefer to learn from others
> experience and expertise than by my own mistakes.
Ah, well that's where we differ. Although I listen to experts, and
(occasionally) read instructions, I don't trust either, and there's no
substitute for conducting your own experiments if you have a basic
understanding of how different materials work.
> Yes, SBR is an excellent bonding agent and waterproofer. Although
> renders based on Pliolite resins based in turn on SBR are often
> microporous, I don't think that mixing your own render using an SBR
> additive will guarantee it will be microporous. It seems that the
> amount of SBR in the render is important to get the best of both
> worlds.
This is a case in point. The basic resin gets developed for a particular
application (this is classed as a synthetic rubber I believe) and the
marketing guys start wondering how else it could be used. Good for paint
because it doesn't have the tacky finish you associate with flexible
coatings and looks the same as normal paint. Floor screeding is another
success for SBR.
As for its use in render, it's immediately obvious that, unlike pva, it
has
no affinity for cement. The SBR separates out after a few minutes and has
to
be constantly re-mixed, so it's a marriage of convenience rather than a
properly formulated product.
As I said, I think the microporous issue is a red herring. For a render
consisting mainly of sand to not allow the passage of air would be some
feat. Things are not so easily sealed to the point of being airtight.
Somebody recently posted a list of surface coatings and their vapour
blocking capabilities, and they were all pretty pathetic. For example, no
amount of paint will stop a piece of wood shrinking to the dimensions
dictated by the ambient conditions, even if the end grain appears to be
sealed.
big...@meeow.co.uk
not with Vic houses
> so it doesn't need to be that flexible to permit movement.
> There's also the chicken and egg aspect. Things that get wet swell
so, if
> you can stop them getting wet in the first place, the movement is
likely
> to
> be less. You can't control movement in the ground below
its standard practice
> but what you do
> above ground helps.
> I don't think anyone has the answer to these problems of maintaining
> Victorian houses without spoiling their appearance and at the same
time
> making them fit to live in by today's standards.
yes they do
http://www.periodproperty.co.uk/cgi-bin/discussing/forum2.pl
> It doesn't help to adopt
> a
> brown eggs and bicycles stance and say we'll just use what the
Victorians
> used. In the case of my current house, what they used was lime with
brick
> dust, which sets just fine (and how else could you lay bricks with
it?)
> but,
> it seems to me, hydraulic lime gives you the worst of both worlds,
the
> brittleness of cement without its good properties.
> I really would like to hear comments from anybody that's actually
used
> lime
> mortar for re-pointing. Was it hydraulic, how long did it need to be
> covered
> etc?
http://www.periodproperty.co.uk/cgi-bin/discussing/forum2.pl
NT
Pete C
<stuart_no...@ntlworld.com> wrote:
>Ah, well that's where we differ. Although I listen to experts, and
>(occasionally) read instructions, I don't trust either, and there's no
>substitute for conducting your own experiments if you have a basic
>understanding of how different materials work.
True, but sometimes it's not practical to conduct experiments, eg
whether a wood preserver will perform well over 5 or 10 years.
>As I said, I think the microporous issue is a red herring. For a render
>consisting mainly of sand to not allow the passage of air would be some
>feat. Things are not so easily sealed to the point of being airtight.
I would disagree with this, any render allowing air to permeate freely
from one side to the other would also be highly porous to water,
defeating the object of using it. Also it would be liable to frost
damage.
Render is also used extensively on straw bale buildings, where air
infiltration through any tiny gaps or pinholes can cause condensation
within the wall.
>Somebody recently posted a list of surface coatings and their vapour
>blocking capabilities, and they were all pretty pathetic. For example, no
>amount of paint will stop a piece of wood shrinking to the dimensions
>dictated by the ambient conditions, even if the end grain appears to be
>sealed.
There are some big differences which is why wood stain is often used
in preference to varnish or paint.
cheers,
Pete.
Mike
> Stuart Noble wrote:
> I really would like to hear comments from anybody that's actually
> used lime mortar for re-pointing.
I'm in the process of doing a large house a section at a time. I also use
lime internally for plastering and mixed with Optiroc (LECA) for use as
insulated flooring. Get through huge amounts of the stuff.
> Was it hydraulic, how long did it need to be
> covered etc?
No - standard Buxton non-hydraulic lime. I never cover it at all, simply
ensure the stone is well dampened beforehand then re-dampen the pointing
where needed in days to come.
I have found the best approach is to put on more than is needed then once it
is set hard wire brush it to the required size. However this only works
with stone - brick would be stained by the lime.
Mike
> Render is also used extensively on straw bale buildings, where air
> infiltration through any tiny gaps or pinholes can cause condensation
> within the wall.
The most common render for straw bales is lime and hence it is permeable to
water.
Pete C
Indeed, there is a good study of vapour permeability and water
absorption of different render here:
<http://www.ecobuildnetwork.org/pdfs/Straube_Moisture_Tests.pdf>
It also shows that a siloxane coating will hugely reduce water
absorption through lime render without reducing vapour permeability.
cheers,
Pete.
Andrew Gabriel
Pete C <pete...@gmail.com> writes:
>
> I would disagree with this, any render allowing air to permeate freely
> from one side to the other would also be highly porous to water,
That's a very sweeping statement for two substances with extremely
different properties. It's possible to make use of the various
different properties (visocity and surface tension are two which
spring to mind and are often utilised) to make a material behave
very differently to water and air permiability. Surface tension
in particular is a very useful property which can be used to either
encourage water permiability via capilarity, or to discourage it
by use of a positive maniscous as often done by silicone based
treatments.
--
Andrew Gabriel
Stuart Noble
> I would disagree with this, any render allowing air to permeate freely
> from one side to the other would also be highly porous to water,
> defeating the object of using it. Also it would be liable to frost
> damage.
anything. Droplets of water are easily repelled by a surface which is a)
vertical and b) not unduly porous.
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Stuart Noble
> It also shows that a siloxane coating will hugely reduce water
> absorption through lime render without reducing vapour permeability.
used for dpc injection, only painted on your wall. I don't think that
would go down too well on the periodproperty site.
Fortunately it isn't a "coating" because siloxanes don't form a continuous
film. They are like tiny pellets of grease which are reasonably effective
until the pressure of rainwater dislodges them.
Pete C
<stuart_no...@ntlworld.com> wrote:
>>On Sat, 16 Apr 2005 11:46:38 GMT, "Stuart Noble" <stuart_no...@ntlworld.com> wrote:
>>>As I said, I think the microporous issue is a red herring. For a render
>>>consisting mainly of sand to not allow the passage of air would be some
>>>feat. Things are not so easily sealed to the point of being airtight.
>> I would disagree with this, any render allowing air to permeate freely
>> from one side to the other would also be highly porous to water,
>> defeating the object of using it. Also it would be liable to frost
>> damage.
>This is the whole point. Water vapour will travel through virtually
>anything.
Hi,
I _think_ you got mixed up between air and water vapour, if you had
said
'As I said, I think the microporous issue is a red herring. For a
render consisting mainly of sand to not allow the passage of water
vapour would be some feat. Things are not so easily sealed to the
point of being a vapour barrier'
that would have made a lot more sense to me, though I would still
disagree.
Anyway IMVHO a lime render with a siloxane treatment will be much more
vapour permeable than a plain cement render, if you feel that they are
more or less the same or the latter will always have enough vapour
permeability then we'll have to agree to disagree.
cheers.
Pete.
Pete C
<stuart_no...@ntlworld.com> wrote:
>
>> It also shows that a siloxane coating will hugely reduce water
>> absorption through lime render without reducing vapour permeability.
>Or Thomsons Waterseal to get technical. The same stuff that's
>used for dpc injection, only painted on your wall. I don't think that
>would go down too well on the periodproperty site.
>Fortunately it isn't a "coating" because siloxanes don't form a continuous
>film. They are like tiny pellets of grease which are reasonably effective
>until the pressure of rainwater dislodges them.
Hi,
AFIAK Thompsons water seal is silicone based, which is quite different
to silanes and siloxanes.
There's a bit of discussion on chemical DPC for period properties
here:
<http://www.periodproperty.co.uk/cgi-bin/discussing/forum2.pl?noframes;read=28223>
As far as Thompsons water seal goes, anything that's pushed heavily to
the DIY market is unlikely to contain a lot of expensive ingredients
;)
cheers,
Pete.
Stuart Noble
> I _think_ you got mixed up between air and water vapour, if you had
> said
I don't think there is a difference in this respect. Air at 80% relative
humidity will travel through anything that isn't airtight and take its
moisture with it.
> Anyway IMVHO a lime render with a siloxane treatment will be much more
> vapour permeable than a plain cement render
How come sand and 20% cement turns into this airtight barrier? IMO
neither
option will offer any hindrance whatever to vapour. If rain water
*droplets*
get behind render then the bulk water cannot get out again, but that has
nothing to do with vapour.
To come full circle, the advantage of the lime is, of course, that it
remains flexible, but I have my doubts about the effectiveness of anything
sprayed on to something as absorbent as lime. Try varnishing a loaf of
bread! What might be interesting is incorporating the siloxanes (the water
based type) into the mortar. Hmm.
Stuart Noble
> AFIAK Thompsons water seal is silicone based, which is quite different
> to silanes and siloxanes.
water repellants, which certainly are siloxanes. Silicone is not used on
masonry because of its film forming properties. The idea with siloxanes is
that the particles remain separate, and can be moved about within the wall
by water pressure.
> As far as Thompsons water seal goes, anything that's pushed heavily to
> the DIY market is unlikely to contain a lot of expensive ingredients
> ;)
wouldn't think so.
Mike
"Stuart Noble" <stuart_no...@ntlworld.com> wrote in message
news:aTK8e.35306$pA6....@newsfe1-win.ntli.net...
> To come full circle, the advantage of the lime is, of course, that it
> remains flexible, but I have my doubts about the effectiveness of anything
> sprayed on to something as absorbent as lime.
The only safe thing to pu on lime is limewash :-)
Pete C
<stuart_no...@ntlworld.com> wrote:
>
>> I _think_ you got mixed up between air and water vapour, if you had
>> said
>
>I don't think there is a difference in this respect. Air at 80% relative
>humidity will travel through anything that isn't airtight and take its
>moisture with it.
I would have thought a lime/sand render is pretty airtight. Can anyone
else comment?
>To come full circle, the advantage of the lime is, of course, that it
>remains flexible, but I have my doubts about the effectiveness of anything
>sprayed on to something as absorbent as lime.
Well siloxane based DPC liquid can be used successfully on genuine
cases of rising damp involving lime mortar, as discussed on the PP
thread mentioned, so I expect siloxanes can be used sucessfully on
lime render too.
Also this company list a waterproofer as being suitable for render,
limestone/sand brick and limestone which is very absorbent, so I
expect it would be fine for lime render too. I'd expect they can
advise in any case:
http://www.remmers.co.uk/s118.html
cheers,
Pete.
Pete C
<stuart_no...@ntlworld.com> wrote:
>
>> AFIAK Thompsons water seal is silicone based, which is quite different
>> to silanes and siloxanes.
>Doesn't say what's in it on the tin, but I guess it's the same as trade
>water repellants, which certainly are siloxanes.
Looks like I was too generous about it, the following page for
'Thompsons Water Seal Ultra Waterproofer' which references the MSDS at
the bottom is revealing:
<http://householdproducts.nlm.nih.gov/cgi-bin/household/brands?tbl=brands&id=20008008>
'Paraffin 008002-74-2 2.9%
Solvent naphtha, petroleum, medium aliphatic 064742-88-7 7-8%'
ie paraffin wax in a base of white spirit. No silicones, silanes or
siloxanes mentioned at all.
For reference, here is a page from the same database for another
product that /does/ contain silicones and siloxanes, being mentioned
in the MSDS though they comprise < 1% of the product:
<http://householdproducts.nlm.nih.gov/cgi-bin/household/brands?tbl=brands&id=16004061>
cheers,
Pete.
Mike
> On Mon, 18 Apr 2005 09:13:42 GMT, "Stuart Noble"
> <stuart_no...@ntlworld.com> wrote:
>
> >
> >> I _think_ you got mixed up between air and water vapour, if you had
> >> said
> >
> >I don't think there is a difference in this respect. Air at 80% relative
> >humidity will travel through anything that isn't airtight and take its
> >moisture with it.
>
> I would have thought a lime/sand render is pretty airtight. Can anyone
> else comment?
Depends on the lime:sand ratio and the mix of sands used. Getting this
right is the key to a good lime render.
Stuart Noble
> On Mon, 18 Apr 2005 09:13:42 GMT, "Stuart Noble"
> <stuart_no...@ntlworld.com> wrote:
>
>>
>>> AFIAK Thompsons water seal is silicone based, which is quite different
>>> to silanes and siloxanes.
>
>>Doesn't say what's in it on the tin, but I guess it's the same as trade
>>water repellants, which certainly are siloxanes.
>
> Looks like I was too generous about it, the following page for
> 'Thompsons Water Seal Ultra Waterproofer' which references the MSDS at
> the bottom is revealing:
>
>
<http://householdproducts.nlm.nih.gov/cgi-bin/household/brands?tbl=brands&
id=20008008>
>
> 'Paraffin 008002-74-2 2.9%
> Solvent naphtha, petroleum, medium aliphatic 064742-88-7 7-8%'
>
> ie paraffin wax in a base of white spirit. No silicones, silanes or
> siloxanes mentioned at all.
Naptha's a lot faster than white spirit, but 2.9% paraffin wax seems like
a
lot of solvent for very little solids. Not exactly environmentally
friendly.
>
> For reference, here is a page from the same database for another
> product that /does/ contain silicones and siloxanes, being mentioned
> in the MSDS though they comprise < 1% of the product:
www.sovchem.co.uk used to have some quite detailed specs about their
products.
Stuart Noble
"Mike" <mi...@nospam.com> wrote in message
news:d418tu$h3j$1...@news8.svr.pol.co.uk...
So a six sided structure could be a vacuum?