damp under wooden floorboards

[AronSearle]

If you block the ventillation to the roomspace, you will increase the risk condensation on inner wall surfaces, unless you insulated the floors and walls to reduce cold surfaces (which you should think about long term anyway).

However, you might find if you make it really air tight*, it may be somewhat cost neutral to run a dehumidifiyer constantly, as you will be getting much less air changes for your heating system to deal with, but it's probably not worth the effort, you are just swapping one energy loss for another.




*caulk the floor, lightfittings, around windows, weatherseals on doors if you don't have them, letterboxes, loft hatches, there are a lot of areas air can leak[/i]

 

[pinenot]

Quite possibly you know these older houses were built in an era where moisture was handled via the both how the house was built and by it's incorporated material. Walls, both external and internal were able to breath, I won't go into lime based construction here (not the right time or place) suffice to say over the years things within these buildings have changed as has modern life, therefore the moisture handling capacity of the home must also change.
I've already mentioned humidistat operated extractor fans for both bathroom and kitchen, and would add anywhere else excess moisture is being produced. One thing has struck me when I went back to read your original post, you mention a well and an automatic pump, has this been checked recently and the drain pipes leading off from this? A leak here could saturate the surrounding ground, perhaps not enough to see but enough to alter conditions like you have described...worth a shot.

Re not replacing the airbricks, OK as long as the original load bearing integrity is maintained.
Re the gaps at the skirting boards, these should be fully draft proofed as long as alternative venting is provided as I have already described.

Have a look at this, could be helpful - http://www.stedmundsbury.gov.uk/pla...nservation/upload/ConservationLeafletDamp.pdf
...pinenot