Sometimes damp issues could be related to a leaking drainage pipe. If you have checked other common causes of damp and have found hey are ok then it may be worth carrying out a CCTV drain survey to all external underground drainage.
If this is something you would be interested in then please feel free to contact me.
It would be best to post the symptoms of your problem in specialist services, Damp Proofing Experts. You should receive three responses with the profile of the specialist who will be able to help you.
If you would like to post another question with the details of the dampness I may be able to assist in diagnosis.
Peter Barber CSSW. CRDS.
We would suggest posting your job under the "Specialist Tradesman" trade and the sub-category "Damp Proofing", simply provide as much detail as you can and up to three of our tradesmen will be able to express an interest in your job and give you a quote.
The Ask An Expert Team