Carport timber size advice wanted

Sean_W

I would like to add a flat roofed (with a small slope) carport to the side of my house. The dimensions are 6.5m long and 3.7m wide. It will be fixed against the house on the long side with timbers running out from the house on the short side.  My question is I'm not sure what size to make the timbers. If anyone can help that would be great. Hopefully my rough picture helps explain what I am trying to do. I accidentally left the baton for the colourbond off the drawing but they will run long ways and colourbond will run away from the house (on the short way)

Thanks

MitchellMc

Welcome to the Bunnings Workshop community @Sean_W. It's brilliant to have you join us, and many thanks for your question about constructing a carport.

Before commencing your project, seek out guidance from your council on local regulations. There's a good chance that a project like this would require a plan drawn up by an engineer and submitted to them for approval.

When selecting your timber, you'll need to consider the weight it is bearing and appropriate span widths. You can research span widths of different dimensions of timber by searching for timber span tables online. Here are some span tables from one of our timber suppliers Hyne. For instance, one of their timbers at 240 x 45mm can span six meters. 

The necessary rafters should be pretty easy to select. You'll need a calibre suitable for spanning the 3700mm width, which can support approx. 5kg per meter. Colorbond sheeting, depending on its thickness and profile, weighs approximately 4.93kg/m2. This likely won't affect your timber selection as significantly as how far it can span unsupported, but it still needs to be considered. The side beam needs to support the weight of all the roof sheeting and the rafters themselves. This is going to be a stretch with a single piece, and you'll potentially need to laminate two boards together or install a mid-post.

Please let me know if you have any questions.

Mitchell