Mould or something else?

[Hellothere]

Hello there - looking at the 100+ year old timbers in our roof and had a questions that someone might be able to help with.

We have a couple of white / off colours sections

The first I’m not sure if it’s mouldy or just old / discoloured from cement or building materials. The wood doesn’t seem brittle and the material is kind of chalky

The second is where we have what look like quite uniform white streaks on roof timbers. Again quite chalky as a texture.

Any advice gratefully received

Thanks

 

[catlad]

Most of those marks are from the old torching when it has been re-roofed and nothing to worry about. The picture of the rafter that meets the ridge has signs of water damage from an old leak in the ridge tiles, You could apply some wood preserver to that area.