Cob...

It all started with a simple enough idea…

“Hey!” I said to a couple of friends. “Let’s put a really big and heavy pipe in my backyard”

We all thought about it for a couple of seconds before they replied, “O.K.”

So I proceeded to a local construction supplier, and managed through my broken German (and his slightly less broken English) to order two 1 meter diameter pre-cast concrete manhole sections, each one half meter high.

I had these beauties delivered on July 3rd.



As usual, not everything went according to plan. The two sections you see in the above photo were different. I ordered one of them with both the top and bottom open and the other had a closed bottom. We wanted to flip the sections over, so that the bottom would be on top. That would leave us with a one meter tall concrete table-top, which can come in very handy.

I reckon that I could also stash bodies underneath it, but that is a whole ‘nuther post.

The guy comes to deliver the sections, and doesn’t speak a lick of English. No problem, all we need to do is point to the location we want it. We are also trying to explain to him that we would like it inverted, and we think he understands. He sets the first section down, but still needs to invert it. Well the rig he’s got on this truck is basically a crane with three chains, each with a clamp on the end. So he takes two of the clamps off, and proceeds to lift the section onto its side, then it’s just a matter of pushing it over.

He then replaces all three clamps, and we’ve got one section in place. “This is great”, I think, “one concrete tabletop comin’ right up!”

Whoa… Let’s not start patting each other on the back quite yet.

Turns out that there is not and easy way to invert the piece with the solid bottom since the clamps can only attach to an end of the section. So we naturally try to set it up on its side, and reason that we can drop it down and muscle it into place. We calculated that it should weigh about 400-500 lbs, and although it would be a bear, there were four of us … surely we could do this.

So the guy starts lowering it, and we’re holding it up … a bit … then when he releases the clamp, Lawrence starts to turn blue.

“Guys…” he says, “this is really heavy.”

We are all starting to realize this same exact thing.

We are thinking that the section is centered enough to balance on top of the other one, but as we gradually let it down we discover otherwise. It just keeps dropping. Lawrence tells us he can’t hold it anymore and we all drop it onto its side.

However, this beast of a thing is weighted much heavier on one end because of the solid bottom. Now when I say “solid bottom”, I mean it has a 6 to 8 inches worth of concrete type of “solid bottom”. So this thing wants to roll back to where its bottom is on … well … the bottom.

So it keeps falling, we are trying to hold it up but realize that it is futile and just try to get out of the way. Lawrence dives back in one direction, Eric and I go off in others and it falls to the ground with a … crunch?

The man who delivered this thing is lying on the ground holding his head, then his knee. I go over to help him, but he waves me off. I see no blood, no scrapes, and he’s clear of the concrete section, so what gives? Then we realize that the concrete section is not lying flat like it should be. Unless of course something, or someone, was trapped underneath.

It turns out that it was the remote control box for the crane that was lying underneath this concrete monstrosity. So everyone was OK, and he worked the crane manually and got the remote out. Funny thing, the remote still worked. So we ended up just putting the sections on top of each other, with the bottom part in the middle.

I was thinking that this damn thing is heavier than we thought. The guy who brought it said it weighed about 600 kilograms, which is only about 1300 pounds. It turns out we were only off by a factor of three. Damn engineers!

So anyway, it sat in my yard just like it is in the photo above until a couple of weeks ago. I had taken a couple of days off work, and went and purchased some bricks, and some sand, and some clay. We filled the half meter deep concrete tube with sand and laid some brick down on top.

The next thing we did was mound up some wet sand…



Then we covered the sand with wet newspaper…



We then proceeded to ignore all child labor laws, and had Lawrence’s kids stomp the clay and sand together…



Of course I added too much water and the mix was too wet. It kept slumping, so this is as far as we got the first day…



Over the next week, after coming home from work, I would work on it a little every night. I mixed about 4 batches of the sand myself, and that is not fun. It’s just like kneading dough, but there’s a lot more of it, and the sand is actual kind of sharp. I was beginning to wish I had gotten married and had kids, just for the free labor.

Anyway this is how it progressed…







If you haven’t already guessed, we are building a cob (or earthen) oven in my backyard.

After leaving it for about a week, I cut the doorway out, and dug the sand mound out from inside …



The second layer (the insulating layer) is going on…



The first fire inside…



Then a big fire a couple of days later…



Perhaps too big…



The crack is not a big deal. I will patch it up with some more clay, and I’m sure there will be more forming as it dries out fully. It still as a way to go, and I still need to make a door and a roof for it.

But I’m hoping to be cooking some pizzas in it this weekend. That is if Lawrence’s kids can come over. I promised them the first pies out.

Of course they will probably be a little gritty too. Maybe I blew it by not having kids; I could have an army of food tasters too.

But if they were anything like me, they probably wouldn’t eat any real food until they were well into their thirties…


There's lots more pictures on my flickr page, just click on any photo.