Purlin bridging water from external wall?

[Dylan T]

Hi all - I’ve got a condensation issue in my loft which I’ve found to be a combination of a poorly fitted bathroom ceiling fan exhaust, loft hatch and lack of ventilation. So it’s a given there’s condensation as on cold days like we’ve had it collects and drips from the felt on the coldest side of the roof.

However I’ve noticed that on this same side one end of the purlin is very wet, and I’m trying to work out if this is related or a separate issue.

The west end of the purlin is in a lot of cement so I the theory I’m most hoping is right js that cement is just absorbing the moisture as perhaps there’s no retardant in it and therefore making the purlin wet. In this case hopefully sorting the condensation will fix it.

However I’m concerned it could be a sign of other water getting in - and hoping some kind folks could help give an opinion. I’ve had two roofers simply say they don’t know.

Thanks!

 

[blup]

Is there any sign of damp ingress via damage to the external wall? Or a flue? If not is there damage to the tiles or felt which is letting in the very heavy driving rain that is more common nowadays?

 

[catlad]

Is that the gable end?