What is happening to my teak decks?

[Puggy]

We get exactly this all the time on our deck in the wet climate of Argyll. In fact it gets so bad that in winter the run-off from the rain down the sides of the boat is full of this stuff leaving trails of it down the sides of hull.

However the deck is coming up to 30 years old and looks good for another 30 years so I'm not convinced that it is degradation of the teak but rather a build-up something or other. It can be easily sponged off and teak below is as hard and smooth as ever.

Thanks for this. Sounds exactly what I am seeing.

 

[KellysEye]

In the picture it looks like something has scraped across the deck , possibly a stiff brush, which should never be used to clean teak. We used a very soft brush for a while but weren't happy with that and switched to a sponge which can't do any damage.

 

[Puggy]

In the picture it looks like something has scraped across the deck , possibly a stiff brush, which should never be used to clean teak. We used a very soft brush for a while but weren't happy with that and switched to a sponge which can't do any damage.

I have actually just scraped my foot across the deck! The decks have been recently refurbished: recaulked and sanded down. I am very careful about not brushing them too hard.