How to prevent mould on decking boards?

Lockmc

I have what looks like mould that grows on my decking boards.

It's a low deck but it does have some airflow at the front, so I'm a little surprised.

I pressure cleaned it all away, but seems to be coming back.

What can I do to prevent the mould?

Do I put something under to divert the water out the front, like some of that black tarp stuff? 

Any advice would be great.  ī

MitchellMc

Hi @Lockmc,

I wouldn't say it's necessarily mould, but it's more likely to be just grey-ed deteriorating timber. Give it a couple of good scrub downs with a stiff bristle broom and Intergrain 1L UltraPrep Timber Cleaner (Garden Safe) - 1L. That should hopefully restore it back to a reasonable condition. You can then oil the deck with Cabot's 4L Merbau Aquadeck Exterior Decking Oil. It contains a Merbau tint to help re-colour the greyed timber.

If it is still very discoloured and mottled after the cleaning process, you might wish to consider sanding it to remove the deteriorated timber.

By the looks of the exposed area, you might need to do a quick 5-minute maintenance coat of oil every six months instead of waiting a year before recoating. This will prevent it from returning to this state in the future.

Here's a helpful guide: How to oil your deck.

Please let me know if you have any questions.

Mitchell