In article ,
Richard Clay wrote:
[snip]
Possible bodge solutions include aralditing or screwing the
drifting piece to the junction, perhaps? And why does it happen?

It sounds a similar problem to one we with a 100ft long
guttering on our factory unit. The guttering lengths used
by the builders were too long, with not enough joints used
to cope with the expansion and contraction. Cut the long
gutter in half, push the guttering over (to close the joint
that leaks), and clip a new joint over the cut ends.

--
Tony Williams. Change "nospam" to "ledelec" to email.