How deep for a foundation for a steel post?

[Cold_Granite]

Hi i was thinking to put a steel patio at my backyard around 7x4m to cover the decking, i was wondering how deep should i go for the steel post foundation 3m high

[MitchellMc]

Welcome to the Bunnings Workshop community @Cold_Granite. It's sensational to have you join us, and many thanks for your question about foundations.

The depth of the foundation for a steel post can vary significantly depending on several factors, such as the overall structural stability, wind forces acting on the structure, the soil type in your area, and how the structure itself is being built. For instance, softer or clay-heavy soils may require deeper footings to ensure stability, while wind loads could increase the required depth depending on the exposure.

Given the size of your proposed patio (7x4m with 3m-high posts), I’d strongly recommend having the structure designed by a qualified engineer. They will be able to assess all relevant factors and provide specific details, such as the depth and type of foundations needed for your steel posts. This ensures the safety and longevity of your patio.

Additionally, if you're seeking council approval for the build, you’ll likely need engineer-certified plans. Most councils require these as part of the application process to ensure the structure meets all safety and building standards.

Please let me know if you have any questions.

Mitchell