Natural Building Workshop: Cob Building, Natural Plastering, Earthen Flooring

Natural Living Skills                  

Expand your natural building skills, learn cob-building and build a cob bench, create an earthen floor, make your own natural plasters and practice artfully applying to finish a beautiful natural cob meditation chapel. Come for the weekend or stay for the full workshop for more hands-on experience. Just 25 miles southwest of Portland, Oregon. Enjoy the quiet and beautiful pastoral setting and get a taste of community life. Camping, daily yoga classes and delicious vegetarian meals included.

Natural earthen floor.
Natural earthen floor.


Hands on Natural Building Experience

Hands on practice with several finishing processes on a recently built cob structure. The workshop includes working with exterior natural earthen plasters for preservation and artistic expression, install an earthen floor and build a cob bench. You will work with different earthen mixes using sand, clay soil natural oils and pigments that preserve and bring luster to wall finishes. Get a taste of all the techniques in the weekend workshop or gain more hands-on experience and finish the project in the full 6-day workshop.

2012 Living With Spirit Plastering the Bale Cob Classroom
2012 Living With Spirit Plastering the Bale Cob Classroom


Beautiful Natural Setting outside Portland, Oregon

The workshop will take place at Ananda Center at Laurelwood, a yoga and retreat center, 40 minutes from downtown Portland. Daily guided meditation and yoga included. Registration is limited to allow personalized hands on instruction. The building site is set on a lovely hillside with views of the coastal range and spectacular sunsets, starry night displays and a fun camp fire circle guaranteed! Enjoy the feeling of deep friendship that comes from building and working together and the family environment of our center with residents, interns and guests.

Instructor Pablo Loayza from Natural Living School

Pablo Loayza comes to us from Natural Living School, located in the foothills of the Sierras at the Ananda Village in Nevada City, CA. At Natural Living School, students learn to construct affordable, naturally built cottages and structures, gain experience and confidence to simplify their lives and create the potential for self-sufficiency. The Natural Living School is also a full service natural build and design company. Pablo apprenticed with Cob Cottage Company in 2010 and has been teaching and creating natural buildings ever since. Check out the Natural Living School site to see some of his latest projects!

Facilitator: John Gorman
Check out the Facebook page at and if you have questions about the workshop, contact at (503) 516-7789

The Benefits and Beauty of Natural Building:

Building with earth encourages one to fully reevaluate how a living space should feel. Our eyes are opened to the beauty of a wall covered with clay plaster, alive with subtle variations of texture, color, and light. Cob and straw-bale walls impart solidity and shelter in a profound way. Structures and surfaces built by hand convey that they were built by people, for people, thus creating a nurturing experience for the sheltered. In contrast, modern industrial materials and design hide the humanity of the creator and frequently expose inhabitants to toxins. Until we are experience an alternative to sterile flat walls covered in plastic paints, we don’t really know what we are missing.

LWS Plastering classroom
Scratch coat, natural earthen plaster









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Laying out the Building Lines For Your Natural Building

Site Preparation

After you select your site, and have a plan and design for your building, then you are ready for site preparation.  The first thing to do is make sure you clear the site where the building will be located.  This means removal of trees, shrubs, large rocks, stumps, or anything that may be in the way of the construction.  If there is a lot of plant life, you may choose to transplant it, or if it’s just grasses you may just mow it down or weed whack it.   If you are planning on having a living roof, you could use the top soil and the plants on your roof, as long as they don’t require lots of space for deep roots.

Laying Out The Building Lines

For the purpose of keeping things simple, lets look at two options.  A round structure and and rectangular structure.

For a round structure; First, pound a stake deep in the ground where you want the center of your building to be.  Make suer it’s deep enough that it won’t move easily if it gets hit on accident.  Then, nail or screw a string on the stake that is the length of the radius of your building.  Pull the string tight and walk around the building marking the circumference of the building with sticks or marking paint.

The trench for a round Sauna we worked on in Aurora Or.

Then remove the top soil and set aside for future use.  At this point repeat the above  process to get the circumference of your inside wall.  Make sure to use the same central stake.  Try not to remove the stake until the foundation has been completed.  You may want to leave it until the roof is done, so that you know where the center of the roof should be.  If you are leaving your stake in for the duration of the building construction, make sure to build a cover for it, so it doesn’t get knocked around.

For the thickness of your inside wall, measure the size of your straw bales first.  Next, add the thickness of your cob, scratch coat plastering, and finish plastering.  For the cob class room, we made the foundation 18 inches wide, because we used 12″ bales (half bales), and added 2 inches of cob on the inside and outside walls, plus 1 inch for plastering.

For a Rectangular Buildings; First you need to make sure that your building lines are squared.  The best way to do this is to start out by setting up some Batter Boards.  These are usually made from 2×4 stakes and 1×6 ledgers that get screwed between the stakes.  Locate the batter boards 4 feet or more away from the building lines.  In most cases you want to make sure your batter boards have enough room for you to move your lines while you try to square the building.  So, place your stakes at least 4 feet apart from each other and use batter boards that are at least 5 feet long.

Batter Board Diagram for your Natural Building

The other important thing to remember is that you can also use the batter boards to help you level the tops of your stem wall. So build all the batter boards at the same height as you want your stem wall to be.  Since we don’t have a transit or a laser level we used a water level to make sure all of our batter boards where at the same height.

Water levels are easy to use and inexpensive to buy.  All you need is a clear tube at any diameter that is long enough to reach all your batter boards.  The reason water levels work is because water always finds its own level.  You can test it yourself, fill the tube with water making sure there is at least 6 inches of space at each end.  Set the two ends next to each other and move one of them up then watch the water level clime on the other end.  It works like magic.

Water Level Drawing from great article on how to use one.

Squaring Your Building Lines; Locate the four corners of your building, using a measuring tape or line, to make sure the corners are spaced out exactly the distance specified in the drawings.  Use temporary stakes and don’t hammer them too deep.   Start with one corner as your permanent stake.  We usually start with the northeast corner, but you can start with any corner that makes sense to your site.   The other three corners can be moved or adjusted to help make the building square.   Using your permanent stake as your bench mark, pick the next stake to make permanent.  In our case we choose the northwest corner, to make sure we have a true south facing building.  If the site allows, use a compass to help you locate the northwest corner.  Now that you have a straight line, the next step is to make sure the 3rd stake is at 90 degrees from your permanent stake.  To do this we use the pythagorean theorem.

The pythagorean theorem is something we learned in school, you may remember it.

If you don’t have a calculator handy, and the distances are not easy to square, then you can use the “3” “4” “5” rule.  First you need to find a common unit.  For example say your building was 12 feet long on side A, and 24 feet on side B, the common denominator is 6, because 3×6 =12 and 4×6=24, which mean that 5×6=30 which should be the distance of side C.  Check it, see if I’m right.

For our building we wanted side A to be 12 feet, and our side B to be 17 feet.  No common denominator there, so we used the pythagorean theorem.

Once you know what the distance of line “C” is (or your diagonal line), then you can move your third stake to make sure both distance “A” and distance “B” are still right, and that your diagonal line (line “C”) is also right.  In our case we knew that the north line (which was our B line), was correct and all we needed to do was find our C line and make sure that the distance was 12 feet.

Squaring Your Natural Building with Batter Boards

Then you repeat the process on the other side and get your building lines squared.  check your diagonal lines to make sure they are both the same.

Once I have my corners set on the ground, then I build my batter boards.   Others use the batter board to find their corner stakes.  Try it both ways, and see what works best for you.

Now that you have your building lines, mark it with marking paint or sticks and remove the top soil from your building site and set it aside for later use.  At this point you can mark your inside walls using the same processed mentioned above, or use the batter boards to mark them.  Again make sure your wall thickness is correct before you move on to the next step.  You don’t want to dig out your foundation trench the wrong size, and have to do it again.

You can see the two yellow string lines, which is the thickness of our walls. The rest of the picture will be explained in a later post.

In our case, we knew that we where going to use 12″ straw bales, (half bales) and 1″ cob plaster on the inside and out side.   Plus we wanted to have some extra room in case we wanted to make a thicker plaster coat.  So we went 16″ wide for our wall thickness.

Now on to the next step, the rubble trench foundation…..

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