Orange coloured dust on floorboards

[brightbluesky]

in the corner of my kitchen several powdery orange small dust piles keep appearing on the wooden floorboards.
I wipe them off and they return over the next few days.
Is this a sign of dry rot or wet rot?
The wall close to them used to have rain water penetration but that was sorted 2 years ago?
Any ideas?

 

[JohnD]

is there a mushroomy smell?

It might be spores, possibly blowing up as fine dust in the gaps between the boards. Dry rot does that. Kitchens are especially at risk as there may be un-noticed plumbing leaks.

Post some pics.

It would help to lift some floorboards and have a look.

This could be expensive.