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We have this timber retaining wall that’s aprox 8 years old that is starting to rot, we are hoping we can do something to stop it in its tracks like cement rendering it etc. we are about to tile the concrete and have our pergola area screened in and the screen will be up reasonably close to the wall.
any suggestions of being able to fix this without having to remove the timber would be appreciated .
Hello @shenmon
Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about fixing your retaining wall.
It looks like your retaining wall has been painted with a clear sealer. If it has, it will need to be removed in order to apply the timber preservative products I'll be recommending. Another issue that comes to mind is that water has passed inside the timber sleeper and caused unseen damage inside the sleeper. I propose testing the rotted portions with a screwdriver and pressing hard on the black sections of the sleeper. If the screwdriver sinks deep and the timber falls apart, then its highly probable that the sleeper is very much damaged and will need to be replaced.
To help preserve your aging timber retaining wall without replacing it, there are a few approaches you can try to slow down the rot and protect it. One option is to apply a timber preservative like Bondall’s Timber Protect, this product penetrates the wood to protect against further decay and can be applied with a brush, focusing on areas that show signs of rot. Just make sure to clean off any dirt or debris before applying.
If you want a more substantial barrier, consider waterproofing the wall with a bitumen-based sealer, like Crommelin’s Black shield. This type of sealer is often used on retaining walls and can provide a water-resistant barrier to protect the timber from further moisture exposure. Applying a few coats on the exposed timber could help prolong its lifespan.
Please keep in mind that this is on the condition that the sleeper is still in good condition and is structurally sound.
Finally, make sure the area around the retaining wall has good drainage to prevent further moisture buildup. Since you’re planning to screen in the pergola area, ensure there’s adequate airflow around the wall, as this will help reduce trapped moisture and slow down the rot.
Let me call on our experienced members @Dave-1 and @Nailbag for their recommendations.
If you have any other questions we can help with, please let us know.
Eric
