Creating Cob: Survival Cement

What are you going to do if disaster strikes and you need to build a new shelter? One option might be to use survival cement, or cob. Cob has been used for thousands of years as a way to build structures. Here’s a look at how you can make it in a survival situation.

Step 1: The first element in the cob equation is mud. How to determine the good mud from the bad and the ugly you ask?

Well, that’s relatively easy: if you make a ball from the potential dirt which retains its initial shape, that’s the droid you’re looking for. You’ve struck gold, and you can go fill a bucket with this mud.

Step 2: You must harvest/gather a respectable armload of straw or dry grasses and  cut them into lengths of six to twelve inches.

Step 3: Next, you must add water to your clay in order to hydrate it enough to a point/density where it will squish relatively easily through your fingers.

Don’t hydrate it too much though; the ideal consistency is if you can mold it and it still hold its shape.

It’s important to find the right consistency. You don’t want your cob to be soupy, but you also don’t want it to be hard and immalleable. Look for a middle ground.

Step 4: You should spread something like a tarp on the ground and put the bucket of homogenized mud and the cut grass/straw at the edges.

Step 5: In the next phase, you must dump the mud from the bucket in the middle of the tarp and put about half of the straw/grass on the top (step five, but who’s counting anyway?).

Step 6: In the next step you must fold a corner of the tarp over the top and stomp it pretty well if you’re barefoot or begin to directly stomp the straws into the mud if you don’t have a problem with getting dirty.

This is the fun part! Work out some frustration by jumping up and down on the mud and straws.

Step 7: Next, after you’ve danced around a bit and the mixture is flattened and spread out, step off the tarp then fold it in half, thus turning the mixture back onto itself.

You should repeat the procedure at least 2-3 times until you form something in the shape of a ball. Then, you must add the remaining straw or grass progressively and start stomping again, until the remaining grass homogenizes with the mud thoroughly.

As a general rule of thumb, the optimum grass/mud ratio is somewhere between forty and sixty percent grass, depending on the type of the structure you want to build.

Step 8: The last step is to start your survival cement project as soon as possible. Don’t let the cob sit to dry out because the mud will harden and it’s going to be very difficult to get it into your desired shape or form.

Basically, you can start building bricks with the cob/survival cement and you can repeat the aforementioned procedure until you have enough (bricks or whatever you’re doing).

If you have to add water to help with the re-hydration of the mud, keep in mind to add a little at a time, to avoid making the cob soupy and thus unusable.

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What are your plans for a new shelter in the event of an emergency? Have you ever tried to make cob before?


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