One of the biggest advantages of building a post and beam frame is you can get the roof on quickly so you can work in the shade and out of the rain and snow. That’s a huge plus. Other advantages include ease of getting code approval and added stability. Use a firewood permit to obtain poles from a local forest and the cost is negligible. Again, check your code situation because many areas don’t allow wood that hasn’t been inspected. (One more reason to move to a sparsely populated rural area with few building codes.)
Another big advantage, and the main reason for doing this blog post, is you can more easily incorporate lightweight insulating earthbags. This would work great in cold areas such as the northern US and Canada. One suggestion is to use scoria or pumice filled bags on lower courses until you’re safely above risk of moisture problems (possibly to window sill height so you have a sturdy base to set window bucks), and then switch to a higher R-value fill material such as perlite or vermiculite. Imagine 15” of perlite at about R-3 per inch. That would get you close to R-45 walls. That’s overkill in most climates, but it would sure be great if you lived where it’s extremely cold. I don’t know of any other wall system that gives you this high of an R-value without spending a load of money on double walls and/or expensive materials.
There are numerous beam options: TJI beam (shown above), laminated beam, beam made of double 2x lumber glued and nailed together, log beam that sits on top of the posts.
Post options include: different types of pier footings and placement either on the interior, exterior or embedded within the wall (shown above). Embedding the posts protects the wood and doesn’t take up floor space. Plus, this method puts the beam right where you want it on the perimeter of the wall.
Oh, and by the way, you can easily pin the corners of earthbags so they fit nicely around the posts. Simply pull one corner of the bag as you’re closing the top and stitch it somewhere near the middle of the bag. Here’s a video of the general idea. Do something similar, but offset one corner more than the other. http://www.youtube.com/user/naturalhouses#p/u/59/Vbs_-jImzPY