In article , Geoff
writes
I'm handy with most jobs but haven't treated damp myself before.
Kitchen wall has rising damp.

What makes you think it is rising damp?

I'm going to drill size 12 holes into the wall and inject a damp proof
treatment. It's a Victorian house and has double walls - do I keep
drilling though to the internal brick wall as well (obviously not all
the way through) Or do I just get to the gap and inject into there?

By "double walls" do you mean a one-brick wall (i.e. nine inches thick)
or a cavity wall - unusual in a Victorian house.

A friend had the work done (he's in Bedford) and couldn't believe it
when he paid hundreds of pounds and the bloke came around and drilled
the holes, put in the filler, and left almost as quickly as he
arrived.

Did he ride his horse into the sunset?

The holes drilled there were about 50cm apart. From what I've
read, that's too far apart. Has he been diddled, or is a little
knowledge worth that much these days?

In the days when people used to have injected DPCs, the aim was to
inject each and every brick until the fluid wet the entire front of the
brick and oozed out of the mortar. In a cavity wall you do the near wall
first by drilling halfway into the brick, then drill all the way through
and halfway into the inner brick and inject the same amount of fluid.

I won't do the internal re-plastering though. The previous occupant
already made a hash of that.

In a Victorian house the mortar will be lime-based, so the plaster
should be as well. Indeed if the previous occupant has used gypsum
plaster that may be why you think you have "rising damp".

What sort of quote should I expect (in
London) for replastering - 1.5, high (to be safe) x 2 metres wide?

As much as they think they can get out of you.

I'll take the existing plaster off myself (anything else I can do
before the plasterer arrives to make his life easier and mine
cheaper?)

Learn to plaster. Its much easier with lime plaster than with gypsum as
you have several hours to push it around before it goes off. Put battens
on the wall, and level up to them with a straight edge, then skim the
following day with a finishing coat.

J.
--
John Rouse