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Dennis laughs at the strength testing process

Rationale

Hello. I'm trying to make a shack using mud bricks. It's been done before, but not by me.

I can build something with floor area of 10 square metres or less, and a few other restrictions, without needing a building permit.

Plans - pff

I haven't drawn any plans or identified an exact site as yet for the shack, though my Mum, whose land I'm building this on, says she doesn't want it visible from the house. Fair call. I don't need plans just now, the bottleneck of the process is making the bricks.

I reckon I'll need about 700 bricks. The brick count is currently 86, and it's not that difficult to make 10 bricks a day.

Guidance available via literature - pff

There is a lot of information out there about how to build using mud bricks. I've read some and taken it on board, but I've favoured a make it up as you go approach. By way of a bit of experimentation, I've found that a mix that is quite wet when the bricks are set makes the strongest bricks.

Rammed bricks - pff

In the early days of the brick making (about 4 weeks ago), I was making the bricks by ramming damp, but not wet, clay into a frame. Some of these bricks were really good, but they took a relatively long time to make, maybe 10-15 minutes per brick. The wet mix means that each brick can be made pretty quickly, somewhere near 5 minutes I reckon, including the mixing of the clay, cement, and water, but not including the time taken to dig the clay out of the ground.

Recipes are for J's

My current recipe, which I didn't have to pay for, I heard someone needed to pay for a special strong brick recipe what a farce, is 18 big shovels of clay, about a cup of cement, and about 2.5-3 litres of water. This makes 3 bricks.

Offal pit

I started digging a hole in the ground to source my clay. Mum wasn't much of a fan of this approach, and suggested that I use the mound of clay that was discarded when we had an offal pit dug. This is working great, I just have to crowbar it loose, sift out the big stones and I'm ready to go. It is not going to last many more bricks, but it has been really good, it's simpler scraping it off than digging it out of a hole.

Ladder frames - the way of the future

The one drawback of my wet mix is that the bricks take a while to dry. I have to have heaps of moulds. I've currently built 3 separate moulding apparati that kind of resemble ladders. They can handle 42 bricks. At the moment, I don't feel comfortable removing the bricks from the frames in less than 5 days. I may need more frames. To get the bricks out of the frames I dissemble them, they are tacked together with nails not fully banged in.

Millimetres - pff

The bricks are 30cm x 15cm x 10cm

Strength testing

One book I had suggested that you should be able to stand on a brick, with it's ends off the ground, and it should not break. Justin reckons this kind of testing is not really relevant, the bricks will never have to take load like this. I agree with that reasoning, however I do want to know that my bricks do have some strength.

When I tested some of the bricks that I had rammed, they didn't fare too well. These were too dry when they were made, and would crumble when I would run my hand over them. Other bricks that were made wetter survived the strength test. I'll try and upload a clip of the strength testing.

My best brick, Dennis, was made real wet, with all large stones removed. It took over a week until I could even remove its frame, it was that wet. It has dried real strong and angular though, and laughed at the strength testing.


Bricks that fail strength testing are dumped back in the wheelbarrow for destruction and restruction.