What could cause fascia boards to seep

[Paul315]

The white K Rend under the fascia board is discolouring brown. It is very apparent in damp conditions though the camera appears to be colour adjusting it away in the photos.

 

It's only affecting one small part of the whole build which is under the width, rather than the length, of the black fascia board.

 

Two roofers and two builders have looked, as have I, and we are all stumped. The tiles and felt overhang into the gutter. The roof above overhangs and keeps the area dry. There's no running water evident in a downpour. The fascia board has been sealed to the wall. Anyone got any ideas?

 

[SteamyTea]

Mould maybe.

If the affected area is mainly in  shadow, has poor airflow and little temperature rise above ambient, moulds can easily grow. They don't have to be just on the surface either, they can survive in the substrate.

Edited October 25, 2020 by SteamyTea

[nod]

You will get patches that are in the shade showing brownish 

As the k Rend is porous

Probably worth dealing with the nasty crack before the frost sets in 

[Paul315]

Thanks both for the swift replies. I'll try some anti-fungal treatment and good point on the crack. I think that before the second roofer attempted to fix it there had been a persistent channeling of rainwater in that patch. That might have given mould a foothold. That area is particularly unlikely to get much Sun too.

[Temp]

I use cheap diluted Tesco bleach in my shower. I'd try that before expensive mould killers which are probably similar stuff.

[nod]

32 minutes ago, Paul315 said:

Thanks both for the swift replies. I'll try some anti-fungal treatment and good point on the crack. I think that before the second roofer attempted to fix it there had been a persistent channeling of rainwater in that patch. That might have given mould a foothold. That area is particularly unlikely to get much Sun too.

If you contact K Rend

Give them the colour They will send you a repair tube free of charge Two minutes for you to gun fill it