I have a 1960 bungalow which had all windows and doors replaced with
double glazed aluminium external doors and windows.
I have several places where damps is penetrating, at least I assume so
as mould is appearing and in one case the skirting board is rotting.
In all cases the ingress is in near the corner of either window or door.
I have had a go in one case by replacing the mastic externally in the
area of the damp on one window, but it is still occurring. Any ideas of
how I can ascertain the cause, and more importantly prevent it?