Help to size framing for flat roof extension. Beam calcs

[cascas]

I am looking to extend to the rear of a brick garage.

Rather than use polycarbonate roofing (which may be easier) I am considering using a timber frame to support the flat roof, so the roof area can be insulated.

The framing will need to support the weight of the flat roof. I can calculate joist sizes from span charts. i.e 47x145 @ 600 centres etc

But how can the sizing be calculated for the timber columns/posts, for the part that is carrying the ends of the roofing joists?

The diagram shows a 4.4m and 4.8m span, interim supports can be added to reduce this, but prefer to keep to a minimum as this area will be glazed with upvc units.

What sizing would others suggest for the base framing.

Untitled

• cascas
• 11 Sep 2012
• 2

 

[chickenlips]

You would really need to find out the loads been applied to the frame 1st.

If your having Glazed UPVC units supported off the frame you will need to find the weight of them as well.

 

[cascas]

The only loading to the frame is from it own flat roof.

The upvc units sit on the brick skirt/foundation so do not impose a loading on the frame.