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Post hole depth for deck

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Post hole depth for deck

i have an area of 2.4 x 4.4 at 300mm height above the ground to build a deck what is the minimum for post hole depth to be dug or the formula please  

Trusted Contributor

Re: Post hole depth for deck

General rule of thumb is 1/3 to 1/2 the length and the width to be 3X the post.

A lot depends on what your soil type is, I tend to go at least 300mm for post depth to be on the safe side.

Bunnings Team Member
Bunnings Team Member

Re: post hole depth

Hello @eddy


Welcome to the Bunnings Workshop community. Thank you for joining us and sharing your question about post-hole depth for your deck.


It's great that you've received excellent advice from @Brad. I totally agree with his suggestion of at least 1/2 the length or more. I subscribe to over-engineering and would probably go past the 300mm as well for safety. Would it be possible for you to post a photo of your plan? It would give us an idea of the layout and provide you with a comprehensive recommendation. It sounds like a fantastic project, any updates you can provide while building the deck would be much appreciated.


If you need more advice or information, please let us know.




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