We've just recently received our building permit after three years working on our DA, BAL, engineering, waste water treatments etc etc... We're constructing two buildings. The "Cottage" is the smaller of the two. The other building can be found
here.
This building has a floor space of just 20 square meters. It will be totally off grid apart from a gas bottle for a BBQ. Construction will be post & beam with mudbrick walls on a concrete slab. Roof & ceiling will be structural insulated panels (cool-room panels). The site has been rated at BAL-29. We will be doing all the construction ourselves, employing trades only where absolutely necessary. (ie: plumber to sign off on our toilet installation & waste water treatment).
We've already made the mudbricks and milled the jarrah structural timber from our property.
Mudbrick making last summer
Milling timber
How do you get your timber certified? Do you use and engineer to check it after it's milled? I would imagine it would be oversize and strength would be based on defect numbers. I'm just about to add some exposed trusses to my build (design stage) and a friend has a swing mill to cut some iron bark. We worked out how to cut the timbers to get the right orientation of the grain, and finding out how to get certification is the next step.
Yes, I will use oversized timbers. Where a 150mm floor joist in MGP10 or 12 might be required I will go with 175mm or 200mm seasoned jarrah which would probably be graded as F14 under AS2082-2000.
As the builder, designer, architect and owner I am ultimately responsible for the structural integrity of my building and in this regard I am answerable only to myself. There are no external checks in this area.
And yes, it is important to get the correct grain orientation when milling timber. I have a "backsawn" pattern stuck on the top of my swing mill safety cowling for constant reference as I'm working.