Hello,

I'm new here and looking for some information on building a detached carport. I'm from Australia and know that the way we build in different countries varies due to different climates. That being said, I'm here to ask for advice.

Currently, the project does not require approval.

I have a customer who wants a quote for a 6 x 5 m (L x W) carport with a flat roof and two sides filled in either with vertical cladding to match his house, or horizontal railings.
He also wants the carport to be built in a way that makes it possible to later (if his wife gives permission) close it in and turn it into a completely enclosed garage with a gate in front.
I therefore suggest an internal height of 2400 mm and a 300 mm I-beam or LVL/glulam for the rafters, OSB boards on top, a damp proof membrane, and then a rubber membrane over the entire roof. It will only have a slight slope, and then a façade will be built around it to make it look completely flat.

My dilemma is that this requires two different building styles. For example, 98x98mm posts would be more than adequate for a carport, or even 48x98. But if they decide to enclose it later, then 48x148 is better to allow space for adequate insulation. Maybe I could laminate two 48x148s together to make the posts, at least in the corners. But if the walls are left like this, that's a lot of oversized material.

I could also build with smaller dimensions, and then – if they decide to close in later – adapt the walls then. But that also feels a bit like a stopgap solution to me.
What are your thoughts on the construction process? I'm open to suggestions on how you would have built the carport, considering his desire to be able to convert it into a garage later.