I made a shelter for the birds using pieces printed with my CR-10.
this shelter consists of:

1 OSB board for the base: 9mm x 300mm x 640mm
2 OSB board for the roof: 9mm x 260mm x 700mm
4 cleats for the columns: 18mm x 12mm x 260mm

Printed parts:

2 roof supports
4 columns supports
4 roof joints (with this system, increase or reduce the length of the shelter according to the number of joints and width of the boards)
4 brackets for fixing (Attention, this type of fixing may not be expected in all situations)

I've placed CURA captures to show how to print different parts to avoid adding supports

I will add more elements to change the rendering when I have a little more time ;-)