The CEB wall is not only made from local earth, but it also has composted manure mortar.
This was not our first choice, but part of emergency Plan B. The ground is pretty much frozen here, and we can no longer make earth slurry mortar. In our case, mortar is particularly useful in evening out the courses of bricks. Our bricks vary slightly in height – so using mortar allows us to even out the gaps. This way, each course can be laid quickly while the bricks remain relatively even.
It turns out – quite interestingly – that our well-composted humus does not freeze – and it is now well below zero. It’s not that the pile lacks moisture – because it is wet after the recent precipitation. I suppose that the water molecules in the humus must be complexed in such a fashion that they simply do not allow crystallization to happen. Our compost pile is as loose and friable in winter freeze as it is in the middle of summer.
This makes our wall supernatural: in adverse conditions – we are able to continue on the CEB wall with ease – when freezing weather almost killed progress because we could not make the standard soil slurry mortar.
See the progress on the wall – after essentially two full days of brick laying with 2 people:
It turns out that the CEB building method is quite robust. While the wall is not the most aesthetic at present, it’s solid as a rock, and it will have no problems supporting a living roof. Building rate is pleasantly rapid and rewarding. You basically stack the bricks one after another, shuffling them on the mortar to assure a tight fit. We have several plumb lines – a weighted string supported from a vertical post – which you can see in the video above. Thus, the walls remain vertical, and we hardly need to use a level. Unevenness does not multiply – as I was concerned that it may – because mortar can be adjusted easily in thickness as needed to level out the courses. Essentially, one lays on the mortar on the entire course, evens out the mortar, and then one can lay bricks one after another.
Personally speaking, progress on the wall is truly rewarding to all of us here. While pressing bricks was difficult due to the manual loading of the machine with buckets – laying the bricks is much easier. Having 24 feet of rollers also helps greatly – in moving the bricks from the pallets to the wall. The rollers turned out to be quite satisfactory – as a cheap homebrew made from 2×4 lumber and PVC pipe of 2 different diameters. This was both easy to do, and useful in practice.
It also turns out that the bricks are strong enough that I have no concern about some of the bricks with cracks. Essentially, one 6×12 brick turns into two 6×6 bricks when cracked in half. There are some bricks that had too much organic matter and sand – which were not suitable for building at all – but most were good. We used the bricks that had visible cracks, and even some bricks that were broken in half on a rare occasion. This is because once additional layers are placed on top, even the cracked bricks are secured tightly. When I tried breaking the broken bricks with a hammer – I was satisfied that cracks are typically what-you-see-is-what-you-get. I mean that the remaining brick sections were still very strong. Overall, the wall is solid like a rock right now.
I was concerned about moisture – but no more – as the freezing weather offers little rain – and snow can basically be brushed off the bricks that are still on pallets. Once we finish the roof – with 4 foot overhangs – and seal the outside walls with plaster and/or sealer – I will not be worried about moisture.
Another detail on moisture is that we laid the bricks on 1/2†treated plywood, 1 foot wide, for the bottom course. We also sealed the bottom course on all sides but the top side with driveway sealer tar – which was easy to apply and dry even in cold weather. The treated plywood lay directly on the 1†gravel foundation. I felt that this solution for a foundation was quite satisfactory. The 18†of gravel is not going anywhere. Plus, once the soil around the structure begins to dry under the roof, and once we install a further moisture barrier on the outside (tar and polyethylene sheet, and possibly cement stucco) – I will not be concerned about any degradation of the bricks due to the presence of water. These types of procedures are standard in all construction, so we’re not doing much different in our case.
Regarding overall ergonomics, if we upgrade our CEB machine loading capacity to mechanized loading with a tractor bucket – then we will have an amazingly ergonomic means of construction. We are in the middle of building a solid structure where the walls will last hundreds of years.
Not bad for building with 100% unskilled labor.
