It's a modern porch on a mostly 1706 building (part of the house is 16th century).
Doesn't smell damp or mushroomy but there is mildew on the ceiling of the porch and discolouration of the paint either side of the beam.
Just bought a house and noticed this very odd dust on a wooden beam in the porch. Thought it was woodworm at first but actually think it's more like a mould/ fungus. It's a bit damp in there. Anyone know what it might be?