bear in mind that wall stability was a perennial probem with lime
built walls. The lime was so slow to set that building progress was
hindered by poor wall stability due to wet unset mortar. Saving a few
pennies on lime would make the situation much worse, it just wasnt
worth it. In fact interior plaster was often overly fat on lime,
economising on lime just wasnt usual practice.
This Victorian pile is built of pretty porous London stocks and lime
mortar - and has no damp proof course.
When I bought it many years ago the BS insisted on a woodwork and damp
warrenty - so I got quotes from several firms. All but one wanted to
install a chemical damp course and re-plaster the external walls up to a
height of 1 meter or so in a waterproof render - which would have meant
removing the beautiful 14" skirting boards, and they would never have gone
back correctly. The decoration in the house was all old, and wallpaper
everywhere. Non of which was showing any damp - or loose. And I bought the
house in the early spring after a long wet winter. No central heating in
the house either. So I concluded if it had survived ok without a damp
course for the best part of 100 years, why did it suddenly need it?
The reason there was no damp showing was simple. The suspended wood floor
was some three courses above ground level, and there was the further 3
courses or so not plastered because of the skirting. Good air circulation
in the cellar too. So any water penetration to the bricks simply dried out
afterwards. If you add a waterproof render to the inside of the wall as
was the practice then, the bricks can't dry out so easily.
There were a couple of minor wet rot problems where joists went into the
walls sat on wood plates which were easily fixed.
*Happiness is seeing your mother-in-law on a milk carton
Dave Plowman email@example.com London SW
What are the other 350 credits about then?
I dread the response...
When my Mum did her diploma in catering management at Battersea Poly, they
had the students undertake every job themselves that they might be expected
to manage others doing in the future, eg cleaning the loos.
One of the students discovered the hard way that acidic cleaners and marble
tiles don't go well togther.
By strange coincidence, Battersea Poly closed and re-opened as Surrey
University, and I worked for a while in what was the same department by a
slightly different name (one or two of the Battersea people were still
Nothing like that now. They still get to do actual cooking and
more "restauranty" things, but no cleaning the bogs or mundane stuff that
I'm aware of.
I've seen far too many fraction of a million projects with a bunch of admin
idiots running the show who won't listen to the people who have to actually
make it work. Usually ends up with the customer side tech folk dealing
directly with the contractors (who also want to leave something that works)
on the quiet to sort out various lack of thought and outright lunacy.
:-) - policy, strategy, design, finance, management, development, bit of
economics/politics/sociology (30-odd credits), dissertation (now called
a project, 40 credits), research methods, marketing, professional
practice, with a year placement. In fairness it's preparation for a job
that's always had an identity problem, swinging between social worker
and property manager. At the moment it's more a regulated portfolio
manager type of course. But it is one of the few courses that does
actually lead to a decent job.
Social housing (20% of all UK housing, about 5 million homes) has
suffered some gross mismanagement. Ironically* (well, not ironically in
my view) most has happened in the past 25 years with the introduction of
managerialism and market pressures. Created a lot of jobs though ;-)
*I gather quite a few on this NG are believers of market over state.
On 2 May, 08:58, firstname.lastname@example.org wrote:
I am familiar with this work and some of the people that did it.
I put forward the possible answer as to why it was the case
RD is actually hygrocopic salt deposition in plaster and mortar.
It happens over decades
I happens mainly in old houses for that reason
Most houses post 1886 or thereabouts had to have a dpc
Put a pile of bricks in WATER and water will be conducted up not
even if salts are in the water there is a huge difference in the
environment of a lab (trying to accellerate a process that normally
takes decades) and the real thing
Walls have an environment which is opent to the air and sun and are
based on ground which is a complex material
The BRE experiments simply did not replicate what happens natrurally
The argument of lime v cement mortar may well be not relevant as
observations that it occures onoly in lime mortar buildings could be
related to the dpc regulation of the 1880s and the introduction of
cement a couple of decades later
interesting, as a lot of them don't. It was quite normal for houses
not to meet local regulations in the 1800s.
good point. Tap water contains salts but less salts make it a slower
... over decades, no. But there are (unintentional) experiments that
have. I must dig up the details when I have time, but to summarise in
some countries masonry houses have been built in rivers, with the
ground floor above the water line, and centuries later no rising damp.
You make some good points.
From a practical pov, I think that damp at the base of walls is much
more often not RD than is. Penetrating damp and condensation, plus
salting due to ground splash or poor use. And piling up rubbish by the
wall doesnt help.
The limit of capillary action is inches, not feet. My house suffered
very badly from it, but it was limited to at best 12" above the local
'water table' - that was with extremely porous brick and probably lime
If you have damn around skirting height, rotten floor joists and blowing
plaster an inch or two above that, its almost certainly rising damp:
Above that its almost certainly not.
Well at least you agree that water penetrates brickwork. Injection stops
that dead. The only issue is whether its capable of rising from where
its in contact with it. My experience says yes, although not very high.
But high enough to be an issue when floor levels are only 4-6" above
very wet soil indeed. Go up a foot or so,and you are mostly out of
danger. However that means a definite 'step up' into the building.
:-) Actually its NOT capillary action in a tree. Its summat else. whose
name I forget.
Ok its is a sort ocapillary action, but not as we normally understand it..
Its not surface tension per se..
You can see it in an un-DPC'ed wall..it comes up from the ground a few
inches..maybe a foot.at most. It doesn't 'cut off' so much as evaparate
out faster than it gets sucked up.
This is where meow gets it muddled, and starts talking about water
proofing making things damp. Of course, if you stop it evaporating OUT
it evaporates IN as it were, and you get soggy plaster.
ergo the typical problem when a crumbling brick plinth is rendered over,
leading to a damp problem inside.., the answer is subfloor injection, to
stop it rising.
My old house had that, both, and it all worked BUT they couldn't inject
the fireplaces/cho=mneys or certain walls that were unreachable and
below floor level in teh middle of the house These suffered massive damp
and rotted the floorbards and led to plaster coming off the brickwork.
The fact that there were underfloor vents just above concret pathways
meant not that the soil under the house was dry, but that water poured
in and formed a lake, in which these internal walls stood!
about 4" up from the lake teh timbers and floorboards rested in these.
They were literally like wet sponges. Being inside the house, there was
no other way that water COULD be getting in except from below.
Two back to back fiers/chimneys and a bread oven all flued up a triple
stack was the other area with major problems Both had been equipped with
Victorian coal excrescences, and the walls then plastered up to those
over the original brick. The plaster lasted bit the paint was peeling
off - I made it good every few months.
If you didn't keep the rooms well heated they stunk of mould. You could
see it all over the bottom 4-5 " of that wall area, but no higher.
Since the whole effigy was about 4 foot thick I didn't see any
possibility of injecting that either.
Correct. You've offered us no experiment that demonstrates your belief
in widespread rising damp, and no logical reason to believe it either.
I've offered 3 experiments that cast great doubt on it, and elementary
logic makes it clear that there is more than one cause of damp at
skirting board level. Bring us some facts you can substantiate.
Your walls are transpiring? I've heard of green buildings, but that's
Actually it's scary reading NP's very good article. Not only does it
contain things I'd forgotten, it also has things in that explain
features of the wood that were "just there" when I last studied it...
That's what happened at my house,
so I've dug a trench around it
and am scraping the crud away and it's drying out,
it's nicely situatied on a local rise,
water drains away in all directions
so i dont need any damp course
in this particular case.
But will put some DPCV plastic under the new floorbaord joists
Which will then rot the joists :-)
Sorry, only kidding.
For sure ther are more ways of tacking damp - even rising damp - than a
DPC, but its simple cheap and very very effective, which is why its used.
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