How to stain a weathered Merbau deck?

Val37

Hello,

I have an outdoor decking that is about 15 year old.

The wood is Merbau.

I believe it was originally stained (not painted) when installed.

Every 2 to 3 years I apply Intergrain decking oil (which has a jarrah pigmentation).

The original stain is now starting to wear out in parts of the decking that experiences the most traffic, thereby exposing the original wood in small spots.

The original stain is NOT peeling.

I look after the decking and is it in very good condition, apart from the minor wear of the original stain.

I was told by a painter that to cover the spots I should apply low grade sandpaper to the affected area with spots and then apply a couple coats of the decking oil.

I have done this in a small area but you can still see the spots where the original stain has worn out (but not as bad), presumably because the oil has low jarrah pigmentation.

QUESTIONS:

1. Instead of applying decking oil, should I apply the Intergrain Decking stain?

2. Can decking stain be applied on top of the existing decking stain that was applied 15 years ago, without causing harm?

3. Must the decking be sanded down first? Is so, should it only be sanded where there is the wear of the original stain or should the entire decking be sanded.

I have uploaded 2 photos of the decking showing a section of the area in question.

Thanks for your help.

MitchellMc

Welcome to the Bunnings Workshop community @Val37. It's splendid to have you join us, and many thanks for your question about restoring a deck.

That's a bit of a tricky one. The original stain appears to not have been an entirely penetrative one and has blocked the pores of the timber. Your subsequent applications of Intergrain decking oil have sat on top of the surface and built up. This is not someone they would recommend, as it can cause their coating to fail; it needs to penetrate into the timber. However, you seem to have been successful in your applications. At this time, I could only advise as per the manufacturer's guidance and suggest that the entire deck be sanded back and re-coated. I understand this sounds a bit extreme, but we now have several layers of products on top of each other, which really limits my ability to provide advice.

You could try a decking stain to mask the worn areas, but I am uncertain how well it will adhere to the existing stain. It sounds like it would be worth a try if it meant you didn't need to sand back the whole deck.

Please let me know if you have any questions.

Mitchell