wondering what this is on wood - mould ?

dada44

Looking at an outdoor, open wooded deck. This is the wall of it. I was wondering what this is - mould ? and the best way to get it off - sanding and revarnish? many thanks










thanks

nickj_2

they are probably mould spores , you could try a pressure washer if you have one, or just give them a scrub , you could get a mould treatment to put on but that could discolour the wood , so if you go down that route try a bit somewhere where it won't show if it does stain/ bleach the wood

dada44

thanks i'll try the pressure washer - is there anything to stop this happening again ? varnish ?