How to raise a pergola height to build a deck?

[brie121]

We have a part of our front yard with a drop-off of approximately 400mm between the lower ground level and the higher yard level. We plan to build a deck over this area at the higher ground level, with a pergola above the deck. However, if we cement the pergola posts directly into the lower ground level and then build the deck, the pergola posts will effectively start 400mm below the deck, making the pergola too short.

Is there a way to raise the base of the pergola posts so they align just under the deck level, maintaining the intended height of the pergola?

I’m unsure if it’s possible to use shorter posts and join them to extend the pergola legs, or if there’s a specific type of raised footing I can use to achieve this. 

Thanks

[MitchellMc]

Welcome to the Bunnings Workshop community @brie121. It's wonderful to have you join us, and many thanks for your question about building a pergola.

To ensure your pergola maintains the intended height while accommodating the 400mm difference between the lower and higher ground levels, there are a few approaches to consider. The simplest solution is to use longer pergola posts that extend from the lower ground level, through the deck, to the desired pergola height. This method ensures structural integrity and avoids potential weaknesses caused by joining posts. 

Alternatively, you could use extended post supports, such as the Pryda 450x90mm M10 Full Stirrup Post Anchor, which allows you to elevate the base of the posts closer to the deck level while securely anchoring them to the lower ground. 

Given that this is an elevated deck, it is highly recommended to consult a structural engineer to ensure the design is safe and compliant with building regulations. This is particularly important when incorporating a pergola, as it adds additional load and wind resistance considerations.

Please let me know if you have any questions.

Mitchell