ive a trimber frame / georgian faced detached cottage-sized property in the s/e; just completed restoration works to re-roof and re-rendered external walls complete, now internal damp has arrived in ground floor internal walls; i have been advised by my builders to take up the ground floors, which are totally furnished and recently decorated. Is thereany other solution to vacating etc.

There are possibly other reasons for your damp appearing internally just now, and as you have recently 'restored' the roof and ext walling (i assume in traditional materials), yet you title your enquiry 'abutment modern to old' . Do I presume the flooring is modern and the recent works traditional. This is probably the most obvious area for the conflict. As modern floors introduce a poly membrane and your walling certainly does not have a damp course. Your builder is offering sound advice; However you could entertain introducing a reduced 'french drain ' within the property and finish with a cast iron grate; similar to what one might see as a ventilation/heat grill in a church . I have recently used this approach and it seems v. successful,; call me with details:

dear carole

we had the same situation where new met old; it is better to have a second or third opinion before going back over new work.

for us it meant creating a physical break at vertical and horizontal levels. which was later covered .