How to remove black marks on Merbau decking?

[craigp1]

Hi there, I want to get my decking looking good again for Summer but I cannot get these black marks off it. 
I have tried timber mould remover and deck cleaner. I have also tried the pressure washer. 
Can I just stain over the top? Or do I have to use another different chemical like tan and oil remover? Or worst case sand back? 
I’m not too fussy but it looks very average right now. 
Any suggestions appreciated 

   

[JacobZ]

Hi @craigp1,

Thank you for your question and welcome to the Bunnings Workshop community, it is fantastic to have you join us.

It looks like overtime your deck has weathered inconsistently leaving sections where the previous stain is still present, and others where it has worn away,

Unfortunately, the only way to get an even coat is to sand back the deck and then recoat it with your choice of product. 

I'd suggest having a look through these step-by-step guides for some guidance -

• How to sand a deck 
   
• How to stain a deck
   
• How to maintain a deck
   

I also suggest having a look at these discussions - Starting again with the deck - sand and strip by @Baz and Deck strip, sand and oil by @DIY_Dan. 

Let me know if you have any further questions.

Jacob

[craigp1]

Hi Jacob,

I guessed that would be the only way but just wanted to make sure.

Thanks very much for your advice and links