Monday, September 30, 2013

One Month In

It has been one month since work began on the cob walls.

The most notable addition in the past week has been the addition of the door frame. This is outside looking in. You can see the brace attached on the left. The frame feels very solid already and could stand on its own but the brace will be left in place until the walls get a little higher.

Inside looking out toward the west through the door frame.

The cob bench was built out during the past week as well. Lots of rocks were added for mass and to reduce the amount of cob needed in the bench.

Here is the bench with the first layer of cob added to the top. This cottage would be perfect for a rocket mass heater with a flue exiting through the bench. I decided against the mass heater for now and heat will instead be provided by a tiny wood stove.

More wiring.

The drain pipe for the sink has been installed.

Looking southwest.

Looking west.

Looking north.

The bench area is going to be a very cozy alcove. There will be a loft above and it should feel perfectly snug when completed.

Things are taking shape.

One day there was a short but intense period of rain. As the walls get higher they will be more challenging to keep dry. From this distance the door frame provides some scale. This will indeed be a tiny cottage.

Another beautiful sunset.

Tuesday, September 24, 2013

Progress Update

Walls continue to rise at a manageable pace. Wall build time so far is 11 half days using 67 batches of cob.

It is clear where the larger of the three front windows will be. There will be a shorter and narrower window on each side of the large window.

 Time to start adding electrical boxes.

Not even electrifying the building was considered. Ziggy bypassed electricity in his cob house and didn't miss it. The computer swung the vote in favor of electricity. Electric service will be a branch circuit from another building or a tiny solar installation.

Inside looking out toward the south.


Here are some images of the materials that are being combined to make the walls for the cob cottage.

Sand, concrete grade. A good rough, sharp sand. 10 yards.

Clay. The pile is being kept covered to preserve moisture. It rained four inches and the clay is nice and soft. I'm hoping to keep it that way as long as possible.

Water. 15 to 20 strokes of the pump per batch.

Mixing station.

In the foreground is my helper and best friend right now, the cement mixer. In the background are the straw bales. 14 bales may not be enough even for this tiny structure. Sand, straw, clay, and water are added proportionally in the mixer in a specific sequence.

Monday, September 23, 2013

A Change In The Weather

There is nothing quite like putting cob on a wall in the coolness of an early morning. What an experience!

The weather has changed. The heat has broken and optimal weather for cob building is near.

It rained a total of four inches at the building site. The walls were covered there was some minor leakage. Surprisingly the walls had no erosion.

The walls are getting higher so it is time to prepare for the installation of the door frame. The frame could be installed this week.

Lots of progress has been made due to the cooler weather. The walls are at least knee high or higher on the exterior side. In places the cob portion of the wall is 12 inches high. The one foot milestone has been achieved!

Ten half-days have been worked to reach this point. Some days have been more productive than others. There have been 61 batches of cob, or an average of 6 per day. It is expected that as the weather cools even more and my technique becomes more efficient it might be possible to add one foot per week. A week of half-days.

The walls are being kept covered to delay the drying of the top layer of cob so additional cob can be added to the top of the wall with a good bond. Apologies for the picture of the covered walls below, but it is the best available right now. Uncovering and recovering walls takes a lot of effort.

Looking west. Visible is the entry way and to the right of that the L-shaped cob bench alcove. A small kitchen will be in the lower right and a table and chairs in the lower left, near the south-facing windows.

Monday, September 16, 2013

Finding Pace

I'm getting closer to finding a manageable pace of building. The heat, my energy level, and progress on the cottage need to be balanced. When looking at day-to-day progress it has the appearance of being s-l-o-w. But when looking at progress in its entirety the progress is satisfying. These walls are growing. And cooler days are ahead so the pace will only increase.

It doesn't look like much but there is progress here.

Looking northeast toward a kitchen area. The stray rocks hold the wall covers in place.

Looking southeast toward a sitting area. Imagine three windows, a cafe table, and two chairs.

Work in progress.

Looking west.

Walls tucked in for the night. Burlap covered by plastic.

Here is a link to some inspiration. Mud Girls Natural Building Cob Workshop via  Wouldn't you just love to live in this cottage? If you have any interest in owner-built homes, bicycle touring, simple living, or a fresh way of looking at things is worth a visit.

Friday, September 13, 2013


It has been hot here. Very hot. Too hot to work on the building. By 11AM  heat stroke is a very real possibility and there is no choice but for work to stop. There is a lesson here - next time start at a different time of year, and build the roof first to provide shade for the builders and cover for the walls.

In the meantime while waiting for the heat to break attention has turned to construction of window and door frames that need to be integrated with the lower part of the walls. Three window frames for the south facing wall have been built as well as a frame for the door.

Here a door frame with a fin being attached. When the frame is installed the fin will be embedded in the cob walls helping to provide stability for the frame.

The door frame and three window frames. The two smaller windows do not have their fins yet. One 24x48 window will face southeast, with a 32x60 and a 24x48 facing south. I hope that is enough solar gain but not too much to overheat the building. The windows will be shaded during the summer season of course.

This is one of several anchor blocks that will be embedded into the cob wall. This one will have one of the door hinges screwed into it when the door is installed. Also pictured is my favorite tool, the Japanese pull saw. Most of the cuts for the frames were done using this very precise hand saw.

A couple years ago I built these instruments and used the same hand saw to cut out the bodies. Little did I know that many of the cutting and gluing techniques of guitar building would be directly applicable to natural building.

On the next building I would like to build window and door frames made from 4x4's for improved rigidity and surface area. I would use dado joints to connect the pieces and perhaps a bracket for extra reinforcement.

The next building? Yes, I'm already thinking forward about another building, a cob / strawbale hybrid, cob / stone / strawbale, compressed earth block, a tiny house on a trailer or even an earthship structure. I don't know if it would be built at this site or somewhere else, like an ecovillage. I'm watching for ecovillage opportunities - if you know of any please do get in touch. I'm would be very interested participating in a ecovillage.

Saturday, September 7, 2013

Finally, Walls

Wall construction began on August 31, 2013. One of the hottest days of the year.

Finally being focused on mixing and applying cob to the walls sure feels good, like a major milestone has been achieved.

The walls are trimmed up below. You can see the initial work on an L-shaped cob bench where the large stones are in the northwest corner of the building.

The Subfloor

There was enough urbanite left over from the foundation to add some real mass to the floor. This will be a passive solar building so the more mass it contains the better.

Large gravel fills the spaces between chunks.

Smaller gravel covers the floor to a depth of 6 inches. I expect to add one to two inches of pea gravel, then perhaps a final layer of flagstone for the actual floor. This could change. The flagstone was donated by a neighbor.

March 2013 and the foundation is ready for cob.

One problem ... the land was no longer supplied with water. The ninety-three year old hand dug well had dried up during the exceptional drought conditions. The problem is now resolved and the solution will be a subject for a future post.


The foundation was built in November and December 2012.

The urbanite was a joy to work with. Most pieces had one flat side which in most cases made stacking easier.

A surprising discovery was that I really enjoy working with stone. But a degree of patience is needed. For solidity the pieces cannot rock back and forth. A stone wants to lay a certain way and finding the right stone to solidly rest in a certain position may take a several attempts. For me laying stone is best left for days when one is unhurried and feeling well.

A short wall along the interior was added.

Formerly a city street - now a foundation.