Straw bale post & beam

About building a post & beam structure... the internet says that one option is to dig the post 4' into the ground. But doesn't wood rot?? How does that work?
I was planning a rubble trench foundation as the water table is high here (3' underground) and the frost line is deep 8' I think). Thank you!!

Putting the posts directly in the ground is generally a bad idea. You can do it using rot resistant or treated posts in areas with well drained soil and deep water table. Even then, I would avoid doing it if you expect the structure to last.  Besides rot, there is the potential for termites and/or differential settling causing trouble.  It just isn't worth going cheap on the foundation of a house you are going to put that much work and money into.

Anchoring the posts to concrete pillars or steel piles would be a different story.  

With a rubble trench foundation, you would normally put anchor bolts in the bond beam and have the posts terminate on the beam with post bases, etc.

Thank you for this post.  I hope you don't mind me piggy-backing on it but I was going to ask the same question.  How do the french drain (or whatever) work with frost lines?  The place I am shopping for land has a frost line 30" (about 80 cm) below the ground.  I am not only concerned about the poles that will support the structure - I would like to do straw bale infill, so need to find a stable foundation for that as well.

D. Moonstone wrote:About building a post & beam structure... the internet says that one option is to dig the post 4' into the ground. But doesn't wood rot?? How does that work?
I was planning a rubble trench foundation as the water table is high here (3' underground) and the frost line is deep 8' I think). Thank you!!

I set a footer ala county code down and then six 5 inch steel posts supported two parallel 15 inch glue-lam beams, which supported vaulted rafters, like a pole barn...sort of. I then stacked the bales under the roof to keep them dry and built the walls out, which was very convenient. The bales were a stair step of bales, right there during the build. All infill. It was stamped by a structural engineer. No all thread from floor to ceiling was necessary. There was a wide chunk of concrete under each post as a load bearing apparatus.

Another option is to use hot dipped galvanised steel posts set into concrete foundations suitable for your area.
They are easier to handle, will not rot or heave.
The posts can be buried with the strawbales.
If you plan it correctly electric cables etc can be run down the inside of the poles for protection and location in the walls.