How to prevent retaining wall posts from rotting?

[brent22]

 

Hello, I have a timber retaining wall on the side of my property. The posts, I assume H5 treated timber, are starting to rot at their tops (due to age, water, sun, mildew, etc.). Wondering the best way to halt and prevent further damage!

[EricL]

Hello @brent22 

Welcome to the Bunnings Workshop community. It's sensational to have you join us and thanks for sharing your question about repairing your retaining wall post.

I propose using Earl's 250ml Wood Hardener. Once the fibres of the interior post have hardened, I suggest filling the gap with Turbo 500ml Builders Bog - 500ml. Once the damage has been covered and the builders bog has cured, I suggest covering the top with either an Ant Cap 100mm Holed Abey Stump or use CAgroup 50mm x 3m Weatherproof Byute Flash Flashing Tape. The tape can be placed in strips and overlap one another to cover the top of the post.

Let me call on our experienced members @Dave-1 and @Nailbag for their recommendations.

If you need further assistance, please let us know.

Eric

[Nailbag]

Hi @brent22 

I would follow @EricL advice on the hardener and builders bog. But then what I have used are Galvanised round metal post caps which are available in various sizes. If the post hasn't shrunk too much they fit firmly to the top with a mallet. You could also securing them with a couple of gal screws if they are too loose. Bunnings don't sell them (that I could see), so just Google "round post caps" for a local supplier. They come in square and rectangular shape too.

Nailbag.

[brent22]

Thank you for the speedy responses. Before applying the hardener should I apply an anti-mold / mildew / insect spray? Or will the hardener also take care of these issues?

[MitchellMc]

You could spray the top with TWA Woodcare 300g Ecoseal Tanalised Timber Treatment, which will restore the H3 treatment. However, the main issue is that water is currently pooling in the top and causing decay to travel down the centre of the post. Harden the timber, fill the area and then prevent water from entering at the top. Apart from a physical cap, you can also paint the top with bitumen paint.

Mitchell

[Dave-1]

Evening @brent22 

I would go the same route that @EricL has suggested. As a side note you could also do a diagonal cut at the top, restore with the earl products and then cap or bitumen paint that @MitchellMc  has suggested. The diagonal cut is supposed to allow the water to run off easier then pooling.

Dave