Where Did All the Pop Cans Go?

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.

The Front Wall…coming down the home stretch of tires!

Construction of the front wall is proceeding quickly … we are now on our third (and hopefully final) row of tires!  We have packed 75 out of a total of about 100 tires for this wall.  Over the weekend the kids helped, and we moved along quickly!  Everybody is tired, and I think the kids are looking forward to getting back to school (they had today off).

We ran out of tires today, and had to go scrounge 12 more to keep going tomorrow.  We are only going to have to track down another twelve or so tires to finish packing tires for our building.  We’ve gotten pretty efficient at packing tires, but I have to say I will be happy to pound my last tire on this project.  By the end of a day I am tired!

Some random thoughts on filling tires … I think I said this in the last post, but do not fill tires in the heat of summer if you can avoid it.  It is a far easier job filling tires in cooler weather and you will get more done (unless you are actively trying to lose weight).  We used a slightly smaller tire on the front wall (225’s instead of 235/245’s) and we found it faster going.  These smaller tires simply need less dirt to fill them, and consequently the work goes faster.  I would definitely consider smaller tire sizes if I were starting my project.

Some notes on the front wall to date …

Sewage connection (Required by the Building Code)

There are 3 sewage pipes out the front of the building.

  1. kids bathroom
  2. kitchen
  3. ensuite bathroom

All pipe and fittings

  • require 2% grade for horizontally laid pipe (1/4″ per foot)
  • must be certified to CSA B182.1 standards
  • 4″ diameter

We may not use all of these pipes but given that we will not be able to add these pipes later we placed them in the wall and will simply plug the ones we do not end up using.  We are running these pipes to an existing septic tank so we shot levels at the tank and at the locations where the pipes cross the wall.  We then determined the relative heights required at each location to achieve a 1/4″ drop per horizontal foot traveled to the tank inlet.  We simply put a 4-6″ gap between two consecutive wall tires where the pipe exited the building and embedded the pipe in concrete to make sure it did not get knocked out of position down the road.  All of the sewage pipes fell in the base round of tires.

Graywater Connections

There are 6 gray water pipes out the front wall.  We do not intend to use all of these, but here again we wanted to make sure the outlets were available if needed.  Essentially, I am trying to make sure there is a pipe at each planter and one for the cistern.  We ran two sets of 3 pipes each; under the first round of tires, and through the second round of tires.  One set will simply not be used but I am not sure at this point what elevation I want so I ran both sets!  Ultimately, these pipes will handle any overflow from the planters and dump it into the septic tank.  Ideally, there will be no overflow.

Electrical Connections

We have decided to run an electrical line out to what will be our front yard.  We do not know what we will use this for …

Water connections

We also decided to run one potable water line out the front wall.  We placed this line so that it was elevated above and did not cross the sewer line.

Filling tires for the front wall of the earthship

I spent the morning figuring out what needed to go out through the front wall of our building; pipes for the sewage system (required by the building code) and overflow pipes for the planters.  We have also elected to put water and electrical lines through the front wall so that down the road they will be available if we want electricity or water in the front yard.

The 4″ black sewage pipe  (shown above) was laid between two tires in the wall at the desired location.  The sewage pipe needs to slope a 1/4″ per foot towards the septic tank.  In our case this means that the top of the pipe going through the wall in the above picture needs to be about 6″ above the ground.  Before we start the next row of tires we will pour concrete in the gap between the two tires and set the pipe in the concrete.  That should keep the pipes from moving until they are attached and buried.

In the afternoon we started filling tires for the front wall of the earthship!  There will be 100 tires in the front wall and we have already filled twelve of them!  This job actually seems easy compared to working on the back wall last summer.  Granted it was only 12 degrees celcius today compared to over 30 degrees regularly last summer.

If you plan to pound tires avoid doing it in the summer!