Hi,

I've been looking round houses to buy, and one in particular I'm
interested in. It's a 1930s terrace, and is in general need of
refurbishment and decoration. However, when looking around the place I
noticed that the wall paper on some of the walls was bulging in places.
Pealing the paper back revealed a gritty white/grey power where the
plaster was crumbling. Does anyone know what the cause of this is, and
whether the walls need replastering or more major work?

The problem seems to occur on all the outside walls of the back of the
house, all the other inner and outer walls are fine. So I'd suspect damp
as the cause. But I can't see any evidence of damp anywhere. No patches
on the wallpaper, the paper is still stuck to the bits that aren't
powdery, no signs of mould, or green inside or out. So, could it be
something else?

Any suggestions appreciated,
-Duncan

Subject: What's wrong with my wall?
From: Duncan Lees duncan-at-snsys-dot-com
Date: 13/08/03 17:39 GMT Daylight Time
Message-id:

Hi,

I've been looking round houses to buy, and one in particular I'm
interested in. It's a 1930s terrace, and is in general need of
refurbishment and decoration. However, when looking around the place I
noticed that the wall paper on some of the walls was bulging in places.
Pealing the paper back revealed a gritty white/grey power where the
plaster was crumbling. Does anyone know what the cause of this is, and
whether the walls need replastering or more major work?

The problem seems to occur on all the outside walls of the back of the
house, all the other inner and outer walls are fine. So I'd suspect damp
as the cause. But I can't see any evidence of damp anywhere. No patches
on the wallpaper, the paper is still stuck to the bits that aren't
powdery, no signs of mould, or green inside or out. So, could it be
something else?

Probably the original horsehair, rat dung and sea shell plaster that my similar
aged house is afflicted with. Nothing lasts for ever and plaster "blows" in
patches in older houses. I'm sure by the time modern ones are 70 years old
it'll be happening to them too. Tap the walls with a knuckle and where it's
blown you'll get a dull sound. You can just rake those bits out and patch them
up again if the rest of the wall is sound. There may well be damp of course but
that needs checking for separately.


Dave Baker - Puma Race Engines (www.pumaracing.co.uk)
I'm not at all sure why women like men. We're argumentative, childish,
unsociable and extremely unappealing naked. I'm quite grateful they do though.

Dave Baker wrote:
Probably the original horsehair, rat dung and sea shell plaster that my similar
aged house is afflicted with. Nothing lasts for ever and plaster "blows" in
patches in older houses. I'm sure by the time modern ones are 70 years old
it'll be happening to them too. Tap the walls with a knuckle and where it's
blown you'll get a dull sound. You can just rake those bits out and patch them
up again if the rest of the wall is sound. There may well be damp of course but
that needs checking for separately.

I've come to the same opinion as well. Since the problem affects the
whole of that side of the house, uniformly from the floor downstairs to
the ceiling upstairs, it can't be primarily caused by damp. I'd expect
it to only affect the lower areas of the walls in patches if it was
damp. So hopefully it's just crap old plaster. It's just odd that it
only affects the one side of the house....

Thanks,
-Duncan

In article ,
Duncan Lees duncan-at-snsys-dot-com wrote:
Pealing the paper back revealed a gritty white/grey power where the
plaster was crumbling. Does anyone know what the cause of this is, and
whether the walls need replastering or more major work?

The plaster's gone 'live'. If there's no signs of damp, it simply ;-)
needs replacing. If you can budget for this, a newly plastered house is
quite an advantage.

--
*Did you ever notice when you blow in a dog's face he gets mad at you? *

Dave Plowman London SW 12
RIP Acorn

In article ,
Michael McNeil wrote:
Knock off the chalk, one or two walls at a time and put 2" x 2"
battens up at 600mm centres or whatever suits the wall/board/you.
Place fibreglass insulation between battens and cover with
plasterboard. Tape and paint or plaster to suit.

This sounds easy, but remember all the skirtings and architraves etc will
have to be renewed, and any ornamental plaster will be scrap.

--
*Why is it that most nudists are people you don't want to see naked?*

Dave Plowman London SW 12
RIP Acorn

stuart noble wrote:
I've come to the same opinion as well. Since the problem affects the
whole of that side of the house, uniformly from the floor downstairs to
the ceiling upstairs, it can't be primarily caused by damp.


I wouldn't bank on it.

Wrong weather for making these judgments. Take another look when we've had a
good downpour. Water can come through the wall at any height.

Don't say that, I've just had my offer on the house excepted! Hopefully
the house survey will tell me for sure what's wrong with the wall.

-Duncan

Dave Plowman wrote in message ...
In article ,
Michael McNeil wrote:
Knock off the chalk, one or two walls at a time and put 2" x 2"
battens up at 600mm centres or whatever suits the wall/board/you.
Place fibreglass insulation between battens and cover with
plasterboard. Tape and paint or plaster to suit.

This sounds easy, but remember all the skirtings and architraves etc will
have to be renewed, and any ornamental plaster will be scrap.

As they will be anyway. Skirting and Archetraves are optional as they
can be reused or replaced with more stylish stuff. And you can just
use straight board if that will do you.

The heat gain will be in the order of £40+ per annum on a central
heating bill I am sure. The resale value is the real safety net for
doing a good job though.

Duncan Lees wrote in message
.. .
stuart noble wrote:
I've come to the same opinion as well. Since the problem affects the
whole of that side of the house, uniformly from the floor downstairs to
the ceiling upstairs, it can't be primarily caused by damp.


I wouldn't bank on it.

Wrong weather for making these judgments. Take another look when we've
had a
good downpour. Water can come through the wall at any height.

Don't say that, I've just had my offer on the house excepted! Hopefully
the house survey will tell me for sure what's wrong with the wall.

I wouldn't bank on that either. It's mainly surveyors and building societies
that have created the myth that all damp is rising. As I said, go and see
the house the day after heavy rainfall. Look upstairs where the plaster is
powdery. Normally you can feel it just by putting the palm of your hand flat
on the wall. Anything facing south south/west is usually more vulnerable.

Good idea about the insulation, I'd not considered that. Might as well
do it since the wall will need replastering anyway. Any idea why the
plaster in the rest of the house isn't doing the same though?

-Duncan

Michael McNeil wrote:
As a 70 or 80 year old house I'd say it's still giving good service.
The walls will be solid though and not heat retentive.

What has happened is that the lime has finally turned inert and is
chalking away from the wall. The reason there is no damp is that the
brickwork is still sound and the walls are breathing.

Knock off the chalk, one or two walls at a time and put 2" x 2"
battens up at 600mm centres or whatever suits the wall/board/you.
Place fibreglass insulation between battens and cover with
plasterboard. Tape and paint or plaster to suit.

The only problem is the wiring and going around window and door
frames. Get around that with strips of moulding or extra architraving.
(Watch out for doors opening onto the studding too.)

If I had loads of plumbing etc in situ on the walls I'd not bother. On
the other hand it's the ideal opportunity to bury central heating
pipes and of course rewiring the leckie.

Duncan Lees duncan-at-snsys-dot-com wrote in message ...
Good idea about the insulation, I'd not considered that. Might as well
do it since the wall will need replastering anyway. Any idea why the
plaster in the rest of the house isn't doing the same though?

-Duncan


Hi

In a similar aged house, we had two walls only that were badly blown
and needed skimming when we moved in. Slightly oddly enough they were
directly above and below each other on adjacent floors.

The suggestion was that they'd been done on a particulalry hot day in
1935, so the plaster had dried a little too quickly and not 'taken'
quite as well as all the other walls. I'm not sure how likely I
consider this to be, but that is what was proposed.

Ours were internal walls. As yours are external I guess a heavy frost
on just that wall might have had a similar effect, as well as the heat
thing which may have affected ours. Maybe they were plastered on the
same day all those years ago?

HTH
IanC

Duncan Lees duncan-at-snsys-dot-com wrote in message ...
Good idea about the insulation, I'd not considered that. Might as well
do it since the wall will need replastering anyway. Any idea why the
plaster in the rest of the house isn't doing the same though?

At a guess I would say because they have had less time to weather. Day
and night temperatures for them will have been pretty constant and
there will have been no damp on the other side of the wall. Lime
plaster is ok for decades only because it was breathing the damp away.

After the insulation all that ability to breathe will end as the
internal air will no longer be so warm. Your house was keeping dry by
heating the atmosphere. I don't know if this means you will need to
vent or polythene. Or both.

Or not.

stuart noble wrote:
I wouldn't bank on that either. It's mainly surveyors and building societies
that have created the myth that all damp is rising. As I said, go and see
the house the day after heavy rainfall. Look upstairs where the plaster is
powdery. Normally you can feel it just by putting the palm of your hand flat
on the wall. Anything facing south south/west is usually more vulnerable.

The prize goes to Stuart. Just got the survey back, and they reckon that
the render on the outside of the wall is porous, and the wall is
uniformly damp. So no obvious staining, but damp all the same. The whole
side of the house needs rerendering and replastering Bugger. Time to
get some expensice quotes from some builders and try to haggle on the
house price...

Chears,
-Duncan

Duncan Lees wrote:
stuart noble wrote:
I wouldn't bank on that either. It's mainly surveyors and building
societies that have created the myth that all damp is rising. As I
said, go and see the house the day after heavy rainfall. Look
upstairs where the plaster is powdery. Normally you can feel it just
by putting the palm of your hand flat on the wall. Anything facing
south south/west is usually more vulnerable.

The prize goes to Stuart. Just got the survey back, and they reckon
that
the render on the outside of the wall is porous, and the wall is
uniformly damp. So no obvious staining, but damp all the same. The
whole
side of the house needs rerendering and replastering Bugger. Time
to
get some expensice quotes from some builders and try to haggle on the
house price...

Exactly same problem with house a relative bought recently.
It is the SW facing wall in this case.
Quotes for re-render alone are ranging from £1k-£2.5k. This is for flank
wall of end-of-terrace in SW London. Biggest problem seems to be actually
getting any builder to commit to doing the job anytime this decade.

BillR wrote:
Exactly same problem with house a relative bought recently.
It is the SW facing wall in this case.
Quotes for re-render alone are ranging from £1k-£2.5k. This is for flank
wall of end-of-terrace in SW London. Biggest problem seems to be actually
getting any builder to commit to doing the job anytime this decade.

I just talked with the surveyer on the phone. He reckons the cost will
be in the "low 1000s rather than the high 100s", so I'm probably looking
at around 2k. But then the brick work may need attention underneath
which I won't know until they start. Just need to get some quotes from
"competent" builders. Anyone know what they are?

Since the wall is damp, dry lining on the inside is also out apparently
since the wall will take a few months to dry out once the render is
fixed. Best get practicing my plastering methinks...

-Duncan

"Duncan Lees" duncan-at-snsys-dot-com wrote in message
. ..
stuart noble wrote:
I wouldn't bank on that either. It's mainly surveyors and building
societies
that have created the myth that all damp is rising. As I said, go and
see
the house the day after heavy rainfall. Look upstairs where the plaster
is
powdery. Normally you can feel it just by putting the palm of your hand
flat
on the wall. Anything facing south south/west is usually more
vulnerable.

The prize goes to Stuart. Just got the survey back, and they reckon that
the render on the outside of the wall is porous, and the wall is
uniformly damp. So no obvious staining, but damp all the same. The whole
side of the house needs rerendering and replastering Bugger. Time to
get some expensice quotes from some builders and try to haggle on the
house price...

Missing the start of this thread - is this a cavity wall?

D

David Hearn wrote:
Missing the start of this thread - is this a cavity wall?

I wasn't sure before, but according to the survey the wall has a cavity.
Oh, and the damp course has been rendered over which is apparently a
separate problem.

-Duncan

David Hearn wrote:
I'm a little confused then - if the wall is a cavity wall - how could water
cross the cavity? Surely, a porous render is not much worse than no render
(apart from it possibly drying out slower) because its still got to go
through/into the bricks/mortar?

I expect that if the render soaks up water and stays wet, then that will
seep into the brick work underneath. If the brick was bare, then it
would stand a better chance of the water running off. Assuming that the
brick was okay underneath the render - No way of knowing until it's
stripped off.

I may have a complete mis-understanding - but I thought that a cavity wall
(unless bridged) shouldn't allow damp to pass through it?

I dunno. I'm surprised that that much damp can make it through the wall
as well. But I guess unless the cavity is a vacuum, water can still
bridge the gap. The air between the two layers of brick will become
saturated from the wet outer brick and transfer it to the drier inner
brick...? I guess the problem would be much worse without the cavity.

-Duncan

BillR wrote in message ...
BTW anybody heard of an alternative to render one builder is proposing to
us?
I think the only long term solution is to have a membrane fixed to the wall
which is then rendered. This allows a flow of air behind it and is in effect
independent of the building itself.
The usual hack off and re-render will almost certainly take you back to
square one in a few years time, especially if the mortar between the bricks
is not replaced.