i'd say it's the vein/heartwood area, is there anyway of getting rid of it or is it best to just paint over it?

i have flat galvanized roof if that's what your asking

would you have any idea what kind of price i'd be looking at if it did come down to replaement?…

Whilst sanding the salmon painted, internal, exposed beams in the kitchen and dining area, i came across something that kept clogging up my sandpaper. After some investigating, it looked to…