Holy crap. I knew taking cob apart was not easy, but to actually try to destroy cob makes it really clear just how strong this stuff is! This is a brief video of me (attempting to) demolish the cob bench outside of my house. This bench no longer fits into the design since I plan to add a small mud room/airlock to the house, and the bench would be in the way.
I tried a sledgehammer, but it wasn’t as effective as a pick axe. Actually, it was easiest when the bench was soaked with water and then struck with the pick axe. Hitting it wet with the sledgehammer resulted in cob flying everywhere.
Cob is stupidly strong. You can see the minimal impact a full pick axe blow has on the bench. What made it somewhat reasonable was prying the urbanite out from underneath the bench, and then really wailing on the cob to break it up.
This cob bench demolition experience is making me sweat when I think about taking the whole cob bed and bench apart inside the house! Good lord… it’s gonna be backbreaking…
Maybe the best method would be to drive metal stakes with a sledge. The cutting point won’t move, so it’s a cleaner cut than a pick axe. As you drive down, craks will form and starting a second stake will direct it. Then the whole thing will come out in one big piece.
next try sawall
Oh man, I’m sorry but I laughed as I read your post. Seeing your frustration tempered by a touch of humor helped make this real. This would be a good video to show people who may still question “stupidly strong” cob, and an excellent illustration why you gotta plan before you build. This doesn’t look quite as simple as tearing out a wall.
Grant: Not a bad idea, but it must be hard to initially drive in those stakes… are you thinking something like rebar or such?
Yes, very thin, but stiff enough not to bend when struck. something like cut pieces of rebar should do nicely, but you would want to put int some sort of point on it. The idea is to just create little cracks so a slab will come out as one piece.
Thanks Zig…. I’m gonna link to this one for those people asking about the strength of cob! Good stuff…. sorry it’s not the last of it for ya though…