Morning All, I'm having a recurring issue with brown staining appearing to come from behind my fascia boards. Back story is that this has only started happening since ive had my house rendered. The new felt flat roof was renewed in June last year and the rendering was completed at the end of October. I've attached a couple of pictures to assist. It appears that the staining is coming from inside the render and appearing above the bathroom window, I dont know what to do now, any advice would be appreciated. I've had the roofers back a uple of times to see if there is anything obvious. Has anyone ever seen this before? Any help / advice would be welcomed.
It's the bathroom. The staining seems to start from the underside of the fascia. It could well be rusty water but would mean water is getting in somewhere.
Does the vent have a metal sleeve that's corroded, can you go into the loft space and take a good look at that area.
The vent does have a metal sleeve, I've just taken the vent off from inside the bathroom and there is sign of corrosion (see below image). Would the rust 'track' like this though, both up and down the wall? It also comes through the render very wet (hence the drips). Its a flat roof so there is no loft space above the area.