The dampness appears to be forming along a horizontal plane, and if this is
at ground level, then it is possible that moisture is creeping along
horizontally. Cracked mortar joint is a common facilitator of this.

Another possibility is that this is a form of condensation dampness, where
warm air has been condensing on a cooler wall - this is common during dry
spells, and especially at the junction of a cold basement and warmer room
above.

If there are no other possible ways for moisture to have reached this spot
by travelling down the wall (such as a leaking pipe or roof), then DPC
failure or bridging is the most probable cause.

For a proper diagnosis, a surveyor or rep from a damp treatment company may
have to have a look.

If you want to DIY, then do a search for injected damp proof course or
similar.

Bear in mind though, that you may need a vertical and horizontal barrier,
and if there is excess moisture in the ground around the wall, then this may
have to be addressed too.

dg


"rocyn" wrote in message
...
i guess it is at ground level

but

the wall is an internal wall - it is not outside facing


"rocyn" wrote in message
...

1.
it appears on the stairs leading down to a basement

2.
on the other side of the wall is a bedroom that i know has had a dpc

3.
it appeared a few moths ago but the patches are getting bigger , so
there
is
no corelation between rain - infact due to the weather we have had - it
would be the opposite .

Thanks for your help

Rocyn





"dg" wrote in message
news
It may be, or it may be some other reaction.

What is on the other side of the wall, and what is the wall
construction?
When did this first appear?
Does its appearance coincide with any rain?
What is the room used for?

dg


"rocyn" wrote in message
...
http://groups.msn.com/Rocyn/shoebox....oto&PhotoID=10

Is this blistering some sort of damp ?

It is appearing on an internal wall - what is it and what can I do
to
sort
it out.

Any help / advice would be appreciated

Thanks

Rocyn