Discoloured roof joist

[rd10022]

Hello all.

Whilst in my loft earlier today I noticed part of one of the joists looked very dark, possibly wet. I've taken a couple of pictures and rather than being wet the last 3 foot or so looks to be a different colour. I can't see any obvious signs of moisture ingress and the timber at the bottom of the joist looks dry. The start of the discoloration is around an overlap point in the roofing membrane and the joist itself is over the bathroom.

Not sure why it would be localised to this part of a joist and it looks as though it is only one side of the joist.

The photos are here:-

//www.diynot.com/network/rd10022/albums/

Has anyone seen anything like this?

Thanks.

 

[gregers]

is that the only 1?
as to me it looks like its had some sort of treatment put on it?something like bitumen??

 

[Nige F]

That white conduit in the foreground - is that drops of condensation on it ?

 

[noseall]

Just looks dirty to me.