How to waterproof treated Pine shed base?

balmainboy

I’ve had to lift my garden shed 90 mm above ground level to comply with council pool regulations. I’ve used 90mm x 90mm treated Pine posts to form a base for the shed to sit on. I’ve now noticed that the timber is constantly saturated as water run off is being sucked into the concrete base. What can I do to waterproof the timber?

JacobZ

Hi @balmainboy,

The typical method is to coat the underground portion of the posts and around 200mm above ground with 2-3 coats of a bitumen membrane before they are concreted in place. If your posts are already in place, unfortunately, to do this, you would have to break the concrete, dig them up, coat them with the membrane and then concrete them back in place.

If you'd like them to last as long as possible, this is the best option. 

Unfortunately, this would be a very painful job. You could hire a Medium Breaker to make the task easier.

The only other alternative that wouldn't involve digging them up is to add a drainage system around the posts to divert the water away from them. If you had some photos of the space that you could upload, I would be happy to offer specific advice, but adding a channel drain in front to prevent surface water from reaching the posts would be a good first step.

Let me know what you think. I will assist further when we can see what you are working with.

Jacob