I have bought a house that needs a new DPC it has rising damp up most of the
internal party walls.
Has anyone installed there own Damp-proof coarse using the equipment from a
hire shop, and how far below the skirting board does the dpc need to be
I am going to remove the plaster up to 1Mt but would also like to know
which add-mix to use with the cement render.
If anyone knows of a good URL with relevant details that would also be
Thanks in advance for any help.
Rising damp? And in the internal party walls? You've been talking to too
many damp-proof contractors, mate!
Rising damp is (almost entirely) mythical. If there is any damp at all, it
will be coming from above - check for leaky roof, showers / bath seals etc.
I did once have some damp at the bottom of an internal wall, but it turned
out to be from the shower (just a short run of cracked grout). The water
ran down the wall in the room below in the space where the lightswitch
cables ran. Removing the wallpaper (we were redecorating anyway) revealed
the line of dampness down the wall with large patches around the switch and
above the skirting board (and saved me £500 in DPC costs)
Whatever you do, don't spend any money having a DPC fitted. It's the
biggest scam going. If the building society insist on it, still don't
bother - they never check that you did it anyway.
Prior to doing all this, are you absolutely sure it's rising damp and
not condensation? Are these party walls solid? Assuming someone has
had a meter on the walls, did they do profile readings or was it just
a case of stick it in, watch it go red and hey presto - rising damp?
What's the moisture content of the skirting board and joists below it,
if there are any (less than 18 percent and they're unlikely to rot)?
You might save yourself a lot of money and trouble here if your lucks
in - rising damp accounts for less than 30 percent of damp problms,
the rest is down to condensation or some other form of water ingress
Oh yes, even the skirting boards are rotten, wet rot.
The whole road (early Victorian) has is a very real case of rising damp.
I have improved the underfloor ventilation, but a new dpc is going to be
essential in this instance.
Thanks for your reply though.
Sorry to hear that...
If the party wall is a solid wall (and being Victorian it almost
certainly is), you can't do an injection dpc. Aside from anything
else, if it did manage to penetrate to the other side then you'd be
providing a dpc for your next door neighbour (in violation of the
Party Wall Act amongst othere things) and they may not want their
You're going to have to use a tanking system (there are lots about)but
you really need unbiased advice on this. Go to www.bwpda.co.uk and
see if you can find a consultant in your area who can give you some
guidlines. It may cost you initially but in the long run you'll
probably save a fortune :)
If it's as damp as you say, tanking may just force the risng damp
higher, especially if there's nowhere for it to evaporate to (for
instanc, into your neighbours domain).
Next door (which has the same problem) has a grant from the council for a
new DPC, unfortunately they have run out of money so it won't get done this
But I don't think they will object too much if I do part of their wall for
Problem remains as to technicalities of doing this.
Thanks very useful.
Im having a paid and recommended Surveyor having a look tomorrow, be
interesting to see what he recommends.
The more I read, im leaning towards the idea of cutting out a line of
mortar and fitting a plastic DPC and then dry-lining.
Dave Plowman firstname.lastname@example.org typed:
Its called the river Bourne !
Runs underneath the entire road, ;-(
I know there is evidence that rising damp does not exist and is in fact due
to condensation/leaking gutters etc.
But I do believe from my own experience that if the sub-soil is damp enough,
with foundations made of bricks/mortar that are now over 100 years old, and
are now so visibly porous you will get damp rising into the living space.
Having knocked the plaster off one wall you can even see it.
The problem is how do you treat it at a reasonable cost.
If it's being cause by a river that is supposed to be running in some kind
of tunnel, perhaps the problem is really due to a break or a general lack of
maintenance by the water company - and something that they must sort out.
It may even be impossible for you to solve your damp problems until they do.
Like Dave said, it's unlikely that people have had rotten skirting boards
for 100 years...
I once did some wiring in a house in an estate which had been built for
water board employees - on low lying land close to a river. The whole of
the foundations appeared to be one big concrete tank - no bare earth under
the floorboards as would be expected in a house of this age. It also was
dug down much deeper - nearly the depth of a cellar although there was no
direct access to it.
I'd be rather worried if conventional brick footings were ringing wet all
the time - they're not meant to survive such treatment, IMHO.
*The man who fell into an upholstery machine is fully recovered.*
Dave Plowman email@example.com London SW 12
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