wrote:

Just wondered what the views are of those who have been through this
before. I am in the latter stages of buying a 4 bed Victorian detached
which has been extended. The structural survey has come back showing
rising damp in the lower walls of 2 downstairs reception rooms. I am a
novice when it comes to 100+ year old properties.

You can almost be guaranteed that someone will find "damp" somewhere in
just about any house. Often the claim of "rising damp" will be made. In
reality this is actually fairly rare, and usually there is a more direct
cause if you look carefully. So check all gutters, and downpipes in the
area. Then look at the ground level - check it has not been raised above
the DPC. Look for covered up air bricks as well.

The Victorian part of the house has no damp proof course from what we
can make out. Is this a concern and should I get one put in?

Most Victorian places will have a slate DPC. Unless the walls have been
cracking up all over the place this will still be there, and still made
of slate! (i.e. failure of a slate DPC is unlikely). It isn't uncommon
to find path levels raised above it though.

I have a damp proof surveyor coming to look at the property on Wed -
though I know he'll say various pieces of work need doing.

Hmmm, be afraid ;-)

Let me paraphrase the report for you:

1) Inject chemical DPC all along walls x, y, and z

2) Hack off all plaster up to 1.2m high, and re-render with sand and
cement containing "new wonder additive" product X that only we can
supply because its our proprietary formulation.

3) Re skim and leave ready for redecoration (*by you*).

For that we will give you a 10 year guarantee so long as you agree to
fix any leaking pipes, gutters, downpipes etc. Lower the level of path
Y, and dig soil away from wall X. BTW you may want to consult a timber
treatment specialist.

Rough translation:

We will come in and bollox up the natural moisture management of you
nice Victorian property. We will guarantee this will fix your problem
only on the condiftion that *you* actually do all the real work that is
required to fix the actuall cause once we have gone. The guarantee we
leave is a good one as long as the company is still trading when you
need it. (BTW. you will notice that we are called Damp Cowboys (2003)
Ltd. That is because we routinely fold the company every two to three
years and open a new one that takes on the previous staff, and assets of
the defunct company, but not the liabilities). Oh, and some jobs for the
boys in our timber treatment devision!

Cynical, me?

Some advice I have read says that Victorian properties are damp period
and you should be wary of going over the top and doing unnecessary
work....

They are designed to deal with moisture in different ways to new places.
Remember also that dampness is not only something outside that wants to
get it, it is also generated in equal measure inside (cooking, washing,
breathing) and needs to get out.

Older properties are traditionally built from materials that are (more)
water permeable than modern buildings. and are designed to allow this
passage of moisture. So water going out, can evaporate from the soft
lime mortar (hence not leaving any salt deposits on the bricks). Water
coming in can evaporate from a large wall surface area (lime and horse
hair plaster that will not fall apart when it gets a bit wet). It
requires that the place is "lived in" to work (i.e. heating and movement
of air) so empty properties will often appear a little damp. It also
required background ventilation (air bricks, plus other drafts normally
associated with older places).

A problem often comes when someone changes a part of the setup without
taking into account the effect on the whole. For example applying some
sort of waterproof coating to the outside brickwork, or re plastering
with a gypsum based plaster, or re-pointing with a cement based mortar.


--
Cheers,

John.

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