Survey - rising damp but no signs of it

[Onaladder]

We are FTBs and in the process of buying a flat we really like in London.
We are moving fast and had everything done within a month and just waiting for the searches.

We did a level 3 survey done, and all things highlighted we can tackle / ok with, but there was one that we are having a hard time understanding - rising damp.

The surveyor noted high meter reading on internal walls in the reception and both internal walls & bay window walls facing external in the bedroom (reading ranging from 70-99). The flat was newly painted throughout after the tenants left and there was no sign of any damp (no smell, no wet spots, no salt spots etc). We had a chat with the surveyor and he recommended we do a damp survey.

We asked the vendor and the vendor sent us reports of damp treatment done 8 years ago. They had the walls put back to the brick, did chemical injection and re-plastered in water proof plaster (sika-1). The damp treatment cost about 2k at the time.

We were wondering whether there is any point in commissioning a damp specialist survey given that an extensive treatment was already done. Should we continue to watch for any signs of damp instead?

Anyone has experience with other types of treatment for rising damp? The internal walls have chimneys so we will have a look at them - the surveyor said to cap the chimneys so rainwater won’t come in, but otherwise they look to be in a good state. No gutters on those side of the walls, they are party walls to the neigbour’s house.

Please could anyone who had similar issues advise what they did? I know there are gurus on this forum who can also provide some invaluable insights! @pigletjohn

Yes do the damp survey!
Did they have any x amount of years guarantee on work they had done?

I've had damp surveys done three times. All said different things and produced different readings. I have a 1920 semi though and we haven't had any actual "real life" damp signals

Fresh paint can hide damp, for a while. As people will tell you, just doing the chemical injection and tanking is not really addressing the cause of the damp, only the symptoms. Usual cause is bad ventilation, leaks and poor drainage. That’s not to say the cause was not fixed 8 years ago though!
If you don’t know enough about houses, or don’t trust yourselves, then get a survey by a damp specialist not affiliated to any damp treatment companies.
However a solid 3 or 4 hours on YouTube should give you all the information you need to identify possible causes of damp, if indeed it does have damp. A damp specialist won’t be pulling up floorboards, though they may have a camera with a light they can stick through an air brick.

@amispeakingintongues that is what I am worried about! That the damp specialist will suggest something and we do it and then there is rising damp again in a few years…or there was no damp in the first place…the more I read about the damp specialists / damp surveys the more I wonder if people truly understand the ‘rising damp’

@OneForTheToad the thing we cannot understand is that they are internal walls! And party walls against the neighbours’ walls so no drainage…could it be only the chimney?

I think they have guarantee, but to the vendor

It could be a leak on the water supply pipe where it goes under the house; a build up of the ground level outside over the damp proof course; a cracked sewer; a high water table ; blocked downpipes; a natural spring; a well...

Have a damp survey done, but not by anybody who sells silicone injections.

Guess what they will tell you to buy?

Can you guess which treatment does not repair leaking pipes, blocked or broken drains, blocked airbricks, or bridged damp courses?