Is a rubble trench foundation legal?
The architect Frank Loyd Wright invented and used “rubble trench” foundations in some of his buildings. Basically you dig a trench down to the frost line, lay a drain pipe in the bottom that slopes down and out to daylight, then fill the trench with gravel. There is no frost heave because there is no water in the trench – it runs out through the pipe. Wright came up with the idea after observing that railroad tracks are not affected by frost because they sit on a raised gravel bed.
I think it’s a great idea, and the few references that I found all praise how well it works. I’d like to use this system in my new house that will start construction next year.
My question is how will this fly with the building permit people – what do I need to convince them that this is a practical foundation? Should I hire an engineer to write up a formal approval, blueprints, etc?? Also, does anybody know of such foundations from practical experience?
BTW my future home is a modest 1,200 sqft retirement house, so it’s not the Taj Mahal or an office building.