Kitchen Damp - Knappen Tubes?

[Snorkerz]

I have a tenanted house some 300 miles from where I live, so I am having to go off 2nd hand information here.

There are very damp walls in the kitchen area on an external wall but (being in a kitchen) behind units. The damp contractor I had visit the place (claims 30 years experience) thinks it is a combination of lifestyle condensation and a broken 1930s damp course. He has given advice to the tenant to reduce condensation but suggested as an initial attempt to solve the problem some sort of fan in the loft to suck the condensation out. I have heard of these before in a positive light and the damp-guy says it [i]may[/i] be enough to deal with the damp wall on the floor below.

He is, however, quite upfront that having spent £700+ on such a fan I may then need to look at geting the damp course reinstated.
A quote is on it's way to me, but that is obviously going to be expensive, expecially in view of removing kitchen cupboards, hacking off plaster, reinstating and re-fitting everthing. This will be extremely disturbing for the tenant and his young son, to the degreee where I am thinking I'll have to add to the bill a few nights in a hotel for them.

Has anyone had any real experience of the damp treatment called Knapen Tubes but also known as Doulton Wallguard, Siphon tube or Hydrotek Wallguard? These are ceramic clay tubes that claim to suck out moisture and then divert it to the outside.
Some info on the web is very positive - but mainly by organisations that sell the stuff. But there is some very negative suff too - predominantly by damp contractors who sell the 'hack it off' type of damp proofing.

So, here's the question, has anyone who doesn't sell damp proofing had any direct experience of theses tubes? And if there are problems, is it with the product or the installation?

[Snorkerz]

Just incase aynone searches for this in future, the spelling should be Knapen Tubes, not double p!

[welsh brickie]

I have heard of them before,In my opinion a total waste of money.And also you mentioned a vent in the loft that sucks out condensation????.If you have condensation in a kitchen on the ground floor how the hell can it suck it through the ceiling and the attic.
If you have condensation in the kitchen then a decent extractor fan installed will do the job.Also an extra air vent will also help greatly.
As for rising damp issue,I certainly would have a second opinion,not from a damp company but from an expierenced builder.