Problem damp corner in front room - condensation?

What im thinking of doing
is marking a few points A B C D...
on some damp places
and every day taking readings with a damp meter gizmo
and writing them down with the day's weather
then a month later make a graph
then somehow figuring out if it's rain or condensation..

(However I know its because of the gaps between some slates)



--

[george]