April 21, 2014

Overview and North Roof

A southeast view of the studio showing some recent 'cobbing' around where the dome will take shape (right-side).  And the North roof parapet wall of cob freshly built-up (dark clay-left side).


Photo below: Shaping cob on top of the north wall, beginning the formation of the parapet wall. 

This roof construction will continue so keep tuned for future updates.

March 31, 2014

North Room Roof In Progress


The above photo shows the current progress on the building, in particular the North room roof which now is covered in 5-inches of "cob" mixed with less clay and more straw to make it lighter. 

This roof will require the addition of a parapet wall , proper water-proofing and drainage that will be discussed in future posts.

February 15, 2014

North Side Roof Line

The room on the north side of the studio will be for the solar power electrical equipment and the battery bank.  The room will eventually be separated by a wall with the other half for storage.  Since this space is essentially a utility area, I decided to make the ceiling corrugated metal for cost and ease of assembly.  You can special order heavy-gauge corrugated metal sheets from a building supply store. 


I like mixing-up the materials in this building.  The metal is not ancient Anasazi architecture for sure, but I was unable to locate the aged wood planks I originally wanted.  This building is not about "intention" in design anyway.  Rather the point is rather that the building is becoming its own eclectic style from the decisions made for various reasons along the way.


The photo below shows about 5-inches of cob in a lighter mix (mostly straw to reduce the weight), that will be part of the evolving roof structure you will see posted in the coming weeks.


January 30, 2014

Time Has its Own Pace

The Photo below of the studio was taken standing southeast, looking Northwest.  Friend and fellow filmmaker Scott Griessel of Creatisa stopped by with his wife Anna for the afternoon and we took some creative time to snap a few photos.  

if you want to see some nice artistic shots of the studio that Scott took on his visit, click on the following link to my "Outpost" blog on Tumblr.  


The photo below was taken looking up at a portion of the southeast room as seen in the photo above, protruding-out.  Notice the band of concrete making up the room's 'bond beam' at ceiling wall height. I plan to finish that exposed concrete with a tile of yet unknown design. 

The drain pipe was recycled from a construction dumpster. Then at the top notice the thin band (2"-thick) of colored concrete as a top-cap to the parapet wall. The top-cap will eliminate the need for re-patching lime plaster in the future (lessons-learned from my adobe outbuilding project). In addition, it will assist future roof maintenance in the future by being able to walk-along and place tools on the top-cap with worry of damage to the wall.

September 23, 2013

North Room Roof Underway

The North side will serve two purposes once the studio is completed.  The room will be divided in two with one half being the battery and electrical room for the solar photovoltaic power; and the other half of the room will be storage for equipment.


I used 6'-Ponderossa Pine vigas to span the narrow width of this 4'-wide room, set roughing 1'-10" apart.  The vigas are 8"-diameter.  As shown in these photos, I then 'cobbed' to the height of the vigas in preparation for the roof decking.

As can be seen in the photo above, the landscape has 'greened-up' from the summer rains.  A protective covering of tar paper was placed on top of the walls for protection from the rains. Now that the fall is approaching, rainfall will be minimal for several months and along with the temperature drop, it will be a good time to work.


(Photos above) A view looking-up from inside of the North room just after the vigas were placed and secured using metal straps imbedded in the concrete bond beam.

August 19, 2013

Concrete Pour-Off for Dome

The base cob wall for the west circular room will support the dome structure.  Since the supporting wall is 2-feet thick, compared to the dome structure that will be between 12-14" thick, I needed to consider rain run-off as part of the design.  The cross-section drawing below shows a triangular-shaped concrete pad (aka concrete pour-off) at the base of the dome that will allow water flow down the dome and off the wall.  This will insure the long-term durability of the wall with minimum future maintenance.


The photo below shows how the 'pour-off" was formed using the same Masonite strips anchored with 4"-deck screws and 1"x 2" wood strips (other examples can be found in this blog).  The Masonite form extends 2" up from the top of the outer cob wall. The other side is 5" in height formed by using cob.  1/2"-diameter rebar in the trench, anchored by vertical rebar in the base wall can be seen in the photo (and the illustration above).


The next photo shows the trench poured with concrete.  I added a brown concrete coloring to tone-down the typical concrete color look.

This next photo shows the completed work which covers about half the circumference of the circular base wall.  The reason why the the pour-off doesn't go all the way around has to do with how the roofs for the remaining two rooms are to be built and will be covered later.  Note: The black tar paper shown on the left, held down by tile fragments is temporary to protect the top of the wall from the summer monsoon rains.

The final picture is an overview of the west side of the building looking east.

June 07, 2013

Cob Roof Fabrication - Narrated Slideshow

There was so much information on the cob roof, that I created this 10-minute narrated video slideshow that details construction of the cob roof for the southeast room.  It's meant to provide information to you 'cobbers' as opposed to entertainment, so bare with it if it seems a little dry.  PLEASE CLICK LINK BELOW


April 29, 2013

Cob Roof - South Room Progress

I plan to post a more detailed account the roof assembly once I decide on the water-proofing membrane and complete the work. In the meantime, I am providing this status photo to document where am at this moment.

The photo shows that the roof has been covered with a layer of cob. However; note that for this (roof) mix I used significantly less clay...so that after the water evaporates from the mix, the cob will be lighter.  The light mix mitigates weight as an issue for the supporting roof beams (Vigas).

The photo also shows that the surrounding parapet walls are taking shape but are still about a 12-inches from their final height.  I use my regular (heavier) cob mix for the parapet walls.


Also, additional cob will need to be added to the roof to provide sufficient slope and contour to allow the water to flow out the drain pipe at the SE corner of the roof.

Here is recap of the built-up roof material used to date: 1) Ponderosa Pine beams (vigas).  2) Bamboo latillas.  3) burlap on top of the bamboo.  4) 2"-Rigid foam insulation.  5) 6-Mil plastic.   6) Light clay/straw cob mix.

April 15, 2013

Mesquite Base for Mounting Speakers

Speaker wire was run through the cob as the walls were being built (see earlier post HERE).  Using a surveyor's level, I marked 10-ft wall height at four locations on rebar equally spaced around the large oval room.

I cut a log of mesquite wood into four pieces and drilled a hole through the center of each piece so the wire can extend out.  But the main reason for using the mesquite is that the wood will provide a strong anchor for the large 1978-vintage Genesis I Physics Speakers that I had restored to provide an analogue warmth to music and other audio to this earthen room.


March 26, 2013

Bamboo Ceiling for South Room

A bamboo ceiling was created for the south room (below) using the two large vigas shown in the bottom photo to support the bamboo poles across the span.  The term used historically and today in the natural building community for this cross support is "latilla".


The bamboo poles were precut to length and holes drilled at the proper spacing between the vigas to help speed the installation once on the roof.  The bamboo poles were secured into the vigas by 4"-exterior deck screws and 1"-washers.  The washers helped spread the clamping force of the screw on the bamboo; and the pre-drilled holes helped prevent cracking and splitting of the dry bamboo.

When the bamboo poles were laid-down, careful attention was paid to select a pole whose orientation would provide a 'crown' for better load distribution and in addition; each pole was selected to best match the pole laid-down before it so the gaps between poles would be minimized.

Preparation of the bamboo involved cleaning the poles with an abrasive sponge soaked with a mixture of water, bleach and a mild cleaning powder.  The mix of cleaners was necessary because the poles were under tarps for several years and showed signs of mold. 
Another major issue was evidenced in some bamboo holes by tiny holes that meant 'powderpost-beatles' were present.  Over time an infestation of these tiny mite-like bugs, can turn these poles into powder.  In order to ensure the beatles would not (further) harm the good bamboo poles, they were all treated with an insecticide, then wrapped in plastic overnight.  Note that 'Borax' will kill these beatles but I was unable to locate borax in time, so I went with the insecticide.
Finally the poles were coated with a wood perservative and waterproofing sealer that helped bring out the grain and color characteristics of each pole (see above photo).
The vigas and latillas are just the start of the roof structure.  In the coming weeks, this blog will detail the buildup of the roof from this point forward.

January 01, 2013

End of 2012 Status Photos

Status photos as of December 31, 2012...

Progress on the roof for the southeast room (below).  Each room will have its own roof level and design.  Cob has built up since the previous blog entry and Latillas can now be laid across the Ponderosa Pine beams.

December 17, 2012

Beams for South Room

A milestone in any building project is reaching the roof. But building a roof is complicated and challenging. My approach here is to make the process manageable by dividing the roof into four separate projects. Each roof line will be at a different level (height).


In the photo, two 10-inch diameter Ponderosa Pine beams 10-feet in length were laid on top of the concrete bond beam of the small 6-ft x 8-ft (south-facing) room and secured by metal straps that are anchored into the bond beam. The beams rest on and extend 12-inches on the bond beam as a best practice approach.

The cob mix (clay/straw) is now being built-up around the walls and in future blog posts I will show how I plan to use bamboo as 'latillas' across the beams to create the basis of the rood deck.

September 03, 2012

Bond Beam Poured for Dome

After completing the Rebar structure that will reinforce a cob dome, the concrete bond beam was poured at the base to support and distribute the weight of the dome.  


In order to "tie-in" the dome Rebar structure to the building's cob wall, horizontal Rebar laid into the channel in which the bond beam was poured.  Vertical Rebar originating from the stone stem wall, was also tied into bond beam completing the connection from stem wall to dome.

August 20, 2012

Initial Dome Framework Emerges

I recently changed my original plan of a flat roof for the kiva room to reflect what I originally wanted to do. This circular room was at first envisioned for a dome when the rock stem wall was constructed. However, since the building's architecture was derived from Anasazi buildings at Chaco Canyon in New Mexico, I changed my mind a planned a flat roof to keep the building's design consistent.

Then with work on the roof structure of the studio commencing; I changed my mind back to a dome for several reasons. First, having studied in the past dome architecture from Egyptian architect Hassan Fathy and Iranian architect Nadar Khalili, it's an asethic that I really found appealing in adobe buildings. Secondly, I wanted the challenge of constructing the dome. And third, I decided that my building process is better suited to reflect an amalgam of architectural styles in order to create something unique and original from a design standpoint.


The picture above represents the initial rebar framework. More framework still needs to be fabricated but I wanted to get the rebar installed before pouring the concrete bond-beam that will support the weight of the dome on the existing cob walls. Thus the rebar frame will be locked into the bond-beam.

The dome itself will be made from cob also with lime-plaster exterior finish. The parabola shape of the dome will make it self-supporting with the rebar frame acting as a safety factor for support, seismic stability and as a guide when lay-up the cob on the walls.

Stay tuned!

July 24, 2012

Summer Monsoon Stalls Progress

I was hoping to pour another bond-beam before the summer monsoon rains started (usually around the end of the first week in July). But by that time I already had 4-inches of water recorded from the rain gauge.

As shown in the photo, there were a couple of inches of standing water due to the dense clay soil. The clay is good for making adobe but not for absorbing water! Clay on your shoes can be very 'slick', so waking about the building site and climbing latters and scaffolding can invite injury.

Lightning also accompanies these monsoon storms, so working on scaffolding with steel rebar sticking-up into the air all around seems like an invitation for an electrical strike. So when I see the storms starting to roll in, I pack up the tools and head indoors.

So until things dry out, I'm doing mostly maintenance tasks around the property. Stay tuned!

June 17, 2012

Second Bond Beam Poured

The second bond-beam was poured over the weekend for the north side 'oval room'. Since each room of the structure will be at a different wall height, the bond beams are being poured separately. The four separate bond-beam pours serve a practical purpose - making it manageable for a lone builder like myself.  The example below is what myself and a helper can do in 4-1/2 hours in 95-degree heat desert sun.  That's how this building is getting done - in manageable and practical building tasks.

The pouring of a bond beam on adobe is a creative challenge.  For the curved walls I'm using Masonite board cut in strips which serve as the form.  Held in place by 4"-deck screws and spaced vertical 1"x2" supports (see photo).  Amazingly, the 'cob' (staw/clay) adobe walls hold those screws rock-solid.

The metal straps sticking-out of the concrete will help secure the Ponderosa Pine vigas (beams) that will support the roof.

Bond beam on cob wall


The difference in wall heights for each room, was derived from personal observation of the project's incremental formation.   It's not just the building's architecture that is driving the outcome.  Practical considerations like water drainage and the availability or amount of 'material' resources required to construct the roof.  Or the design may change for one part of the structure building resources lying around that I just want to use up.

The roof is a massive undertaking for an individual.  But designing with these limitations in mind are proving a way to innovate around the problem and that's where a lot of satisfaction from this process is derived.

The result so far has been no major compromises.  Sometimes you learn from the building as it evolves, which way is the path forward.

May 28, 2012

More Bond Beam Prep

The west-side (Kiva) room has reached ceiling height and preparation work has begun to pour a bond beam. The photo below shows how I discovered that a sheet of inexpensive masonite board, could be cut in strips to act as a form for the eventual pouring of the concrete beam.


I like Masonite because it has a high strength-to-weight ratio and it's flexible.  And as one can see from the shapes of the rooms in this structure, I need that flexibility to accommodate these irregular shapes.  I hold the masonite in place securing 1"x2" pine strips into the cob with 4"-deck screws (see photo above that shows these vertical strips).   

I cut 12"-wide strips from the 4'x8' sheet of Masonite. Then I drew a line 5" down on each strip to denote the height of the bond beam channel.  The 7" of  board below the line is pressing up again the cob and utilized in holding the cob to the wall.

I'm amazed at how the "cob" wall can hold those screws tight.  I used this 'securing' method in a previous bond beam pour, the result of which can also be found in the top-left portion of the photo. I'm fairly confident I won't have any blowouts in the form when the bond beam is actually poured.  

I still need to install rebar in the channel prior to the pour.

The outer portion of the form is the rising cob wall.  Notice in the bottom photo a simple measurement  'fixture' I devised to ensure a 12-inches wide channel.  The fixture was moved around the back-face of the inner portion of the Masonite form as cob was applied to the top of this 24"-thick wall and up-against the fixture.

April 09, 2012

North Room at Roof Height

The photo below shows the north room walls at roof height (for the most part).  The string along the rebar was set with a surveyor's level in order to ensure the wall is completed at a uniform height.  Provision for an outdoor light fixture can be seen at the bottom-left of the photo. 

This strangely shaped room will be divided in half with one section used for storage and the other side will be the 'utility' room for the solar power electronics and the battery bank to store the solar energy.  This section of the room will have its own separate entrance via a small 2-ft wide door (see bottom photo).


The photo below is a ground view of the same part of the building (north wall shown above.  The entry door to the utility room is clearly visible along with the freshly laid 'cob' along the top.

Southwest View

Below is a status photo of the northeast side of the studio showing the main entrance.  The recently finished wall height can be seen along the north wall (darker wet cob).  The next step will be to set up forms and pour a bond beam by similar method to the small room on the south side of the building (left side of photo).  See bond beam blog entry HERE


February 27, 2012

Speaker Wire Routing

In the photo below, Tonia chisels-out a channel in the cob in order to route speaker wire vertically down the wall.  At the bottom, a hole was drilled through this interior cob wall in order for the wire to emerge in another room on the other side where the audio/visual entertainment components will be placed.


The photo below shows the completed routing ready to be covered-over by a layer of cob. A further discussion on the speaker wire placement will be forthcoming once the walls in the 'large room' reach 11-feet in height where the speaker wires will emerge for each of the four speakers.


January 06, 2012

Large Calcite Slab Placed in Kiva Room


I became obsessed with translucent nature honey-amber colored Honeycomb Calcite after seeing it at the Tucson Gem Show in Tucson back in 1999.  So much in fact, that I formed a entity to sell the stone after developing a business relationship with the owners of the calcite mine. I saw the potential of the stone as an artistic architectural element in the adobe buildings I was designing for the future at that time.  The future has arrived as the building projects are moving forward. 

As envisioned for the studio building project, I took the largest stone I had in my calcite inventory and spent several days removing the white outer layer of the stone with chisels and a grinder.  Then with the help of two friends, raised the 197-lb stone up scaffolding to the position where it was placed on the north side of the circular 'kiva room'.  To hold the stone in position, rebar was employed as bracing using protrusions in the stone as handles for the rebar to rest against.  

The thickness of the wall at this location is approximately 3-feet, thus the stone will not be illuminated by sunlight.  Instead, a solar-powered lighting system will be installed in a wall cavity behind the stone in order to illuminate its features for viewing inside in the kiva room.  Future posts will show additional building steps for both the wall and the lighting installation.

January 02, 2012

Southeast Room


This extension (shown at right in top photo), added off the southeast side of the main (large) room, was envisioned as additional space.  But more importantly, I saw the need to add a passive-solar gain room to collect sunlight in the winter months.  Since a french style door will separate this room from the main room, it could be closed at night to retain the heat in the large room accumulated from the passive solar style design.

In the above photo of the solar gain room, the concrete bond beam (discussed in previous blog entries) is shown at top hugging the curved wall.  The stone stem-wall extends up 3-feet from the footing. The room dimensions are approximately 7'x10'. Ceiling height for this space will be about 8-1/2 feet.

November 08, 2011

A Footing in the Sky Poured


The Masonite forms as discussed in the previous blog held-up excellent during the pour.  The concrete mix for the bond beam was 3-gallons water, a half-bag of Portland Cement (47-lbs) and 350 lbs of gravel/sand. This recipe was derived from several books I have on concrete that would give me a suitable mix for footings and foundations.  Initially, I weighed a 5-gallon bucket with the sand/gravel mix. It came in at 70-lbs.  So then I knew to add 5-buckets to the mix in order to achieve the 350 lbs called for in the recipe.

Myself and a helper took 3-hours non-stop to mix the concrete (6 mixer batches) and haul the concrete up scaffolding in buckets to accomplish the task. Approximately 1-ton of concrete was used in this pour.

To begin working on the roof structure is a psychological milestone.  There is still additional 'cobbing' to be done to raise the main room's wall height to 12-feet, so effort over the next few months will switch back-and-forth from working on the walls to working on the sections of the roof structure.

November 07, 2011

Devising a frame to support the bond beam pour


Since the start of this building project, I have been thinking about how I would set-up framework to pour a concrete bond beam (description mentioned here) on top of the cob walls at ceiling height.  

In short, the bond beam ties the wall with the roof through the use of vertical rebar from the footing through to the roof structure.  In addition, the bond beam act to distribute the compression load from each viga supporting the roof structure as it rests on the bond beam.

The challenge for this building design is to support the frame around curved walls.  Since the width of the walls for this southeast part of the building are the minimum desirable thickness structurally (12"-17"), this necessitated that the bond beam span the full width of the wall for the entire length of the room.  To achieve this, the support frame had to fastened to the outside of the cob wall.  This fastening method had to be figured-out.

I was also thinking about what material would be flexible enough to bend around the curves of the walls; while at the same time knowing the material had to hold firm during the pouring and curing of the concrete.

I decided to go with 3/16"-thick Masonite (sold in 4'x 8' sheets) for the bond beam frame and 12"-long 1" x 2" furring strips to support the Masonite.

For the frame, I cut 12" wide strips of Masonite, eight feet in length from the sheet.  I pre-drilled three holes in the furring strips in order that the screws securing it to the cob walls, wouldn't split the wood or make the attachment process more difficult.

The screws I chose were 4"-long deck screws (course thread).  I was impressed how the cob (straw/clay) mixture held the deck screws extremely firm when attaching the furring strips in support of the Masonite frame.

The photo at top shows the completed bond-beam form prior to pouring the concrete.  The photo at the left is a close-up of a section of the wall.  The rebar used was 5/8"-diameter and additional furring strips were attached across each side of the wall to provide additional stability to the forms. 

In the top-left quadrant of the photo above, there are two "Simpson Strongties" - a trade name for metal straps that will be secured in the concrete beam and rise vertically to attach the viga to the bond beam.

Upon the completion of the bond beam's support fabrication, I knew I had tackled the challenge of the form's design and implementation.  But I still had to mix and pour the concrete beam, so I was careful not to declare the design a success just yet.

August 25, 2011

Clay/Straw Walls Hold Strong After 12-inches of Monsoon Rains

Artistic Note: Regarding the photo below, check out the clouds in the background.  My camera's imaging chip seems to have made those clouds look 3-dimensional and painterly - a cool effect!  To get a larger-size view, click on the photo.

The cob walls have held-up well, with little erosion, over the course of this year's summer monsoon season.  The rainfall tally (so far) is over 8". It's quite amazing how cob holds up to the pounding monsoon downpours.

The walls are now about 8-feet tall on the southeastern room of the studio.  Therefore I need to establish the final height for this section of the building, which will be lower than the (adjacent) room, that will have a higher wall height wall height that is adjacent to the north of this room.  I used a surveyor's level to assist in establishing final height.  I'm there in the background holding a ruler (this one too big to take to school) that I'm using in conjunction with the survey level.

I struck a line on the scale at a point on the wall that I considered final height.  Then at intervals along the wall where there was vertical re-bar sticking up, I moved the ruler up or down until the line I made on the scale was in the cross-hairs of the surveyor's level (My wife was attending the level - Thanks honey!!).  Then I made a mark on the re-bar at the height of the line I made on the ruler.

Next I ran a string (as shown in above photo), tight along the mark made on each piece of vertical re-bar along the wall.  The string now represents a uniform height. Now I can build-up the wall with cob to the height of the string and be confident that I have a "level height" along that section of the wall.

August 23, 2011

Summer Harvest of Sand and Gravel

To the left of this photo is a rock check-dam (a.k.a.Gabion) which helps keep soil in place when the dry-wash across my access drive to my property flash floods during the summer monsoons.

A few weeks back a flash flood deposited an enormous amount of sandy-gravel across the driveway. This sand is just what I needed for the bond beam I will soon be constructing along the top of the cob walls of my studio. The bond beam helps support the wall and tie together the wall and roof structure.  In addition, the bond beam will distribute the loads carried by the wood vigas that support the ceiling and roof structure.

Below. Drawing showing representative bond beam placement on adobe wall.
Drawing Source: Earthbuilders Encyclopedia by Joe Tibbets

 A side-benefit of the gabion slowing-down the water, is that it allows the deposit of sand.  This is an example of how you can harvest resources from your property for use in natural building.  A result of constructing the gabion is a renewable source of sand for my building projects.  

There is a financial savings aspect to this also.  A 10-yard truck load of sand is around $150.  But because Arivaca is so far off the beaten path, the sand/gravel company adds another $125 for the delivery charge.  So that's almost $300 in savings in exchange for the physical labor in moving the sand myself.

For my blog on the construction and status of this gabion see: