12m x 6m gazebo with a double roof -- 2

Job ID: 40221149

Budget: $30 – $250 CAD

Good day I am looking for a structural plan for a small 1 story 12m x 6m gazebo.

I have some sketches of a summer season enclosed gazebo I want to build in my backyard (measurements are in feet). I am looking to convert that sketch into a structural plan.
My main concerns are about:
1. The monolithic concrete slab thickness in the center/edges, footing depth / width, ...
2. What thickness wood beams/pillars be needed for the roof?
3. I would like to have a double roof, while optimizing the living space under the roof by having exposed ceilings, and minimalizing the amount of rafters and hopefully not have any columns in the center of the room.
In my area (near Montreal, Quebec, Canada) the building code requires:
- 2.5kPa snow load and
- to be able to withstand 120 kmh wind gusts.

In short what I am asking for is a STRUCTURAL PLAN.
How much will you charge for a structural plan for this simple gazebo?

Thank you,
Alex