Darfield Earthship

Where Did All the Pop Cans Go?

Posted on 22. Apr, 2010 by Chris in Bond beam, Can walls, Construction, Earthship, Front Wall, Graywater, Tires

We’ve been robbed!

After months of collecting pop cans we had BAGS of cans squirreled away in our storage shed.  When I popped my head in the shed yesterday to admire our collection I realized most of the cans were gone and there were just a few lonely bags left …

The culprit was not very far away. We finished the pop can form for the concrete bond beam on the front wall today. We estimate there are around 1600 cans in this form. Compared to pounding tires this is fairly easy work; it only took us a few days to lay this form, and it was not particularly strenuous. We used nine 40kg bags of portland cement to make the 80 foot long form. I am not convinced of the value of making the form this way instead of using lumber. In this case I did not want to use lumber and leave it in place due to proximity to the planters.

The concrete (or mortar) used for these pop can walls cannot have coarse aggregates (read rocks) as any rocks larger than about 1/2″ in diameter starts to get thicker than the mortar laid between the cans and weakens the wall. Consequently, we re-screened our aggregate using a mesh with 1/4″ spacing. We will have this same problem when plastering the walls … I see a lot of screened gravel in our future! The good news is that we started saving the rocks as we screened and we are now collecting rocks for the planters.

Before we finished the can form we had to lay the last twelve tires of the front wall. We did not lay these tires earlier as we needed to be able to drive the backhoe into the building. For the last two days we have been digging a trench inside the building along the front wall. Talk about a bull in a china shop! With the front wall built there was not a lot of room to manouever the backhoe and digging was a challenge. Fortunately I only struck walls with the bucket a couple of times and thank god they are earth filled tires … nothing broke! I have no idea why there are cracks in the pop can form though … maybe the kids were playing too close to it? Regardless, no serious damage and with the last tires in place we will not be getting the backhoe back into the building.

The trench is for the gray water planters along the front wall. We dug the trench in the approximate shape of the planters to a depth of two feet. The planters do not take up the entire front wall, but we wanted to lay pipes between them so that ultimately the planters all have the same level of gray water. Once we laid the connecting pipes (2″ black ABS) we buried the pipes so now only the planters are dug down. The pipes will enter the planters right near the bottom and guarantee that the level of water in all the planters is identical. In other words the pipes should prevent overly dry or swampy planters. Hopefully it will not rain significantly until the roof is on as I hope to leave these trenches until we start the gray water planters after the building is closed in.

Tomorrow we are getting more gravel … we’ve run out. Hopefully on Friday we will pour the bond beam on the front wall. After that we move on to the roof and framing the front wall.

NO MORE TIRES!  It was hot the last couple of days we finished the front tire wall … the outside thermometer read over 30 degrees celcius yesterday.  I am happy not to be pounding tires this summer!

We have 861 tires in the building … but who is counting?

I’ve added photos to the front wall gallery and created a planters gallery.