! the first wofati - allerton abbey- version 0.7

We have been plugging away at the Allerton Abbey project bit by bit over the last few days. By we, I mean Carol-Anne and I. The pace of work has definitely slowed since all of the volunteers left, but we are making progress nonetheless. I finished carving an angle into a 2x10 to serve as a window sill, as well as cutting a curve into one side to wrap around the post, and installed that into the window buck. The wall is just waiting for a delivery of new dry straw, so we moved on to other parts of the project for now.

I used the tractor to dig out a deep hole about 10 feet out from the wall, so that we can lay in the insulation and watershed umbrella away from the wall and down 4 feet. What you see in the picture is the contour of dirt draining away from the building, that will be covered in a thick layer of sawdust for insulation, then several tarps will be installed over that. On top of everything will be placed more dirt, so that most of the umbrella is under about a foot of dirt. A deck is going over much of this as well, and will protect the umbrella near the walls where there is not as much dirt covering it.

I spent most of yesterday driving "Ellie Mae," a huge old Ford flatbed truck, to the lumber mill to pick up one unit each of 2x6's and 2x4s. It is pretty cheap to buy them in this quantity, about a buck a stick, but I must say there are some pretty ugly sticks in there. Once I got the units back to base camp we found out that they were far too heavy to unload from the truck using the forks on the tractor. So me and Josh had to unload a bit at a time and re-stack them by hand in the berm shed.

Carol-Anne has been keeping on with the cob work over the last few days, but isn't enjoying working alone as much as when there were other people to stomp cob with. We could really use some extra hands and to make for quicker work and some nice company. I've put up a thread about the ongoing cob and straw work party for the Allerton Abbey project, so if you have been wanting to learn some natural building skills go check it out.

I got my hands into the cob today along with Carol-Anne, and we were able to nearly finish the plaster layer on one of the wing walls. The logs are all completely covered on the vertical section now, except for two that stick out more than the rest which we are going to leave exposed so there is somewhere to attach things to the wall if needed. Plus, one of the logs is all twisty and cool looking so it will add a bit of art to the wall. The overhangs above the vertical wall may be a bit tricky to get plaster to stick to, so we may just fill in the gaps between the logs, leaving the wood exposed. A lot of the poles up there are now covered in bits of cob, so unless we can clean them and make the filled cracks look nice, we may end up having to plaster upside-down.

Jesse and Carol-Anne, you're doing a great job! As a self employed carpenter I know what it's like to get bogged down on a job with no one to help (no fun there) but try not to get discouraged. Hopefully, someone will respond to your plea for help and really get things going again! It'll be really exciting to see how this new design performs during the winter.

Nice work! I am curious as to how the cob will hold up on the log substrate. Wood is not the ideal material for cob to stick to, and would benefit hugely by putting a steel mesh onto the logs first. The wood expands and contracts with the humidity, and even a little amount will crack the cob. Hopefully this won't be true for you guys.

Ernie and Erica didn't think the lath was necessary, though I'm not sure why. I may try putting some down just to see if it speeds up the plastering process, and also along the upside down sections of the wall to make plastering that easier.

Tim Wheaton put some cob in the 2nd WOFATI similar to this technique (directly into the log joints). Maybe analyze the status of those areas to verify its success. If it's not cracking and falling out I'd be surprised.

So I tried doing a little bit of plastering using the lath, with poor results. The undulating shape of the wall makes it so the lath will not fir snugly against the surface, leaving spaces behind it. Even when cob is pushed through the lath into this void, the lath still has a tendency to lift away from this underneath layer leaving a void between the two. I have used lath and plaster before, but It seems to behave differently with the cob mix we are using. Perhaps chicken wire would work better, though with much less reinforcement strength. I think no matter what we do, over time the cob plaster will crack, as we are dealing with an exterior wall made of many different sizes of logs which are all expanding and contracting at different rates. The purpose of the cob plaster in this application is not structural, but to provide a surface to be white washed, reflecting more light into the house.

Progress! Yesterday was all about getting the insulation/watershed umbrella installed in front of the new wall. In the morning we took the fire truck and the 5 yard dump trailer to a local friend with a sawmill to pick up a load of fresh sawdust to be used for the insulation layer. Once we returned we started preparing to install the umbrella. Before putting any of the tarps down, I used the tractor to move enough of the sawdust for a good thick layer over the big hole I had dug earlier. First we pushed some of the sawdust down the slope of the hole, then we laid out the bottom layer of tarps, Bilboards material several layers thick. This edge of this went in the bottom of the hole, them I moved a few loads of dirt over it to bury the botom of the tarp over the insulation layer and pin the whole thing down.
After this, we spread out the sawdust over the whole area, leaving some room near the walls to attach the upper layer of tarps. To do this, we tucked the top edge of the tarps around a 2x6, which was then screwed into the 2x6s I had previously attached to the bottom of the walls, so that the tarps were wrapped over the outer 2x6 and pinched in between the two. It sounds simple, but when you are dealing with multiple layers of 15x30 foot tarps, crawling underneath them to get to where you can screw the boards down, and trying to make sure it all stays tucked in... well we got it done anyway.
Once that was done, we pushed the sawdust up underneath the tarp/wall junction and spread it all out to a uniform thickness and proper slope away from the wall. Then the bottom tarp wads pulled up over the sawdust, the top tarps were pulled down over those, and a third set of tarps were put in between those two to fill in a little gap that was left between the two. All of the tarp layers are arranged like roof shingles, so that water will flow down and off. Finally, I covered up everything with a layer of dirt, retaining the proper slope. Next we will build a deck over the whole thing.

pictures from yesterday

Wow.

It's a bit late for this consideration, but did you account for any plumbing, specifically gray-water, or other conduits, perhaps future wiring to a bank of solar panels, that may need to run through this area?