This thread prompted me to have a check in the loft at the weekend. We had a small brown patch appear a couple of months ago on the ceiling of one of the bedrooms. It’s dry and hasn’t got any bigger and our loft is difficult to move around in as the insulation has been laid thick and over all of the beams, so had been putting it off. Think there may be some water damage on one of the beams/struts/trusses (what are they actually called?).
Got someone coming out to take a look tomorrow. So thanks for the prompt
from my own experience -
with the recent cold spell - the icy blast - a lot of lofts can accumulate condensation because of both this extreme weather (for this country) and the fact that inside a loft it needs to breathe so an empty loft is much better for air to circulate (breathe)
so you will get damp patches showing on ceilings where moisture has gathered but this is only a real problem if it persists - it can cause mould bu that can be treated, and ceilings might need a coat of paint but usually this is all it is
once the weather turns back to 'normal' then your loft should be able to breathe again once more
but always check the loft if noticing damp patches or water marks or mould just in case there is a hole (usually a broken tile and nothing more) or worst case scenario, a leak from the plumbing but that would manifest itself as a persistent patch
rotten wood would be the result of a long term problem that needs immediate addressing