Tuesday, March 26, 2013

Rammed Earth in South Carolina

The Church of the Holy Cross, a Gothic Revival structure designed by Edward C. Jones gets a lot of attention when it comes to historical earth construction, but it did not spring from the soil without regional prescendent.

In 1821, Dr. William W. Anderson, a Maryland native, used the technique to rebuild the wings of the Borough House, the main building at his Hill Crest Plantation, and several outbuildings. In 1850, Anderson persuaded the Episcopal congregation of Stateburg to use pisé de terre in constructing the Church of the Holy Cross.

The big house has rammed earth on the main floor. It would be nice to get a look at those footings.

 Everyone likes plans!

 My favorite building on the compound is the doctor's office. Dig its Federalist austerity.


The Borough House and its outbuildings constitute the largest complex of pisé de terre buildings in the United States, recognized as National Historic landmarks, hence these lovely photos from The Library of Congress.

Saturday, March 23, 2013

Tapia Pisada in Columbia / Pise en Colombie

Bien sur, c'est en francais! C'est d'accord, nous sommes tous bilingues au Canada.

Construction des murs de pise en Barichara, Colombie. Nous n'avons pas besoin d'une brouette!

This project is dedicated to create Artepolis, a convention center and training for art and culture in
Barichara, Colombia,
We are aiming to create a meeting platform for artists. We are hoping to invent, through the arts, new ways of sharing cultures. The artists will work, during their stay, with the locals, colombian artists and the other artists in residence.
The focus is on meeting and sharing European and Colombian cultures.
It is of paramount importance that the workshops should include the locals in order to interact with them.

This will be the best way of sharing cultures and the artists themselves will start a closer relationship with the local culture that will in turn enrich their own work and will allow them to invent new educational methods around it.
 Barichara was declared a National Monument in 1978 because it is a beautiful example of the architecture at the time of conquest. This place is considered the most beautiful village in Colombia, thanks to the craftsmen who worked the stone to build houses and churches.


Friday, March 22, 2013

Rammed Earth Aircraft Dispersal Revetments, Edwards Air Force Base, Kern County, CA

Rammed earth has a long history of use in the United States military. From the Library of Congress:

"Eleven rammed earth revetments were constructed during World War II to provide shelter and cover for aircraft in case of an attack from the Pacific. The revetments are strongly associated with the war effort and are among only a few remaining World War II era buildings and structures at Edwards AFB. Two different designs were constructed, one for bombers and another for pursuit aircraft. The method of construction employed, utilizing layers of earth and aggregate tamped into a form, is unusual and may be unique. Although six of the revetments are extant, only two revetments were found to be eligible for listing in the National Register of Historic Places."

Dig the eerie beauty....

A Good Idea That Never Gets Old

Rammteck in Zululand

Check out these inspiring videos showing the David Rattray Foundation's efforts in using rammed earth construction to further their goals of eliminating poverty and illiteracy in Natal, South Africa.

Georg Maybaum - Building with rammed earth | Cohabitat Gathering 2012, Ł...

Dr Georg Maybaum, Head of the Institute for Soil Mechanics and Foundation Engineering and  professor at HAWK in Germany is seen here giving a presentation on rammed earth construction at the Cohabitat Gathering in Lodz, Poland last year.

Budowla Ziemi w Polsce

There is some exciting stuff happening for rammed earth in Poland...

The very innovative use of corrugated formwork found here, for instance:

I want to try this at home, vertically!

This structure exudes both rustic charm and modern sophistication:


Wednesday, March 20, 2013

Rammed Earth Workshop Spring 2013

Looks like esteemed Canadian rammed earth builder Clifton Schooley is having a workshop on Saltspring Island in April  29 – May 11 of this year. 

Clifton was a builder on this lovely ampitheatre at The UBC Botanical Garden as well as guest expert at Green Home Building dot com.

Enjoy his low-pressure approach!

Tuesday, March 19, 2013

Great Wall of MIT Redux

Way back in the olden days of this blog, near the middle of the last decade,  we had some words with Joe Dahmen about his Great Wall of MIT project.


Recently we found ourselves strolling the sunny streets of Cambridge, Massachusetts and thought to check in and see how the wall has withstood six cold winters.


The wall was very thoughtfully designed with steel plates installed to give information about the soil mix at various levels of the wall.

 As you can see the soil ratios are sensible. You can't get too fiddly with your proportions when you're working at such a large scale.

 It reads (in all caps):
Financial support: Office of the Dean, MIT School of Architecture and Planning  MIT Council for the Arts Boston Society of Architects Sasaki Associates Inc.
Material Donations: Modern Continental Construction JF White Contracting Co.
Project Team: Teagan Andres Charles Mathis Omar Rabie Shuji Shuzumori
Project Designer: John Ochsendorf
Designer/Team Leader: Joe Dahmen

If you have environmental concerns about using cement stabilizer in your rammed earth walls, and you have somehow managed to convince All Who Would Thwart You to allow you proceed using regionally available clay, this is likely to be your final surface, unless you go in for plaster (stucco is cement after all) and even more labour.
While you can see bits and pieces of the wall crumbled on the ground, keep in mind that there's been six winters of unsympathetic Massachusetts snow removal against it. It is still a formidable structure despite the surface concerns. Perhaps if you were imprisoned within similar walls you could, with time, scratch your way out, but if you tried to drive a car through them, that would be the end of the car. It would take several generations of cattle to rub those walls away.

As has been mentioned in numerous documents regarding historical rammed earth, the part of the wall closest to the soil and the drip line are the most prone to erosion. It would have been interesting if they had left the roof cap off one section to see how much of this erosion is caused by drips falling from the small over-hang and splashing up from the ground versus how much would be caused by water infiltration from the top wall surface.

 The surface is definitely looking better under the steel cap.

Still pretty bony though. I think if you're going to go to the trouble and expense of ramming a wall with labour costs what they are in the First World, you'll want a more durable surface than what we're seeing here. Still a worthwhile experiment, though.

Typical Rammed Earth Wall Section

Since I've been getting some questions lately, I thought it would be instructional to put up a section drawing of the rammed earth walls in my house so you can get a look at my engineering specifications.

In Canada, rammed earth construction is not covered by the building code, so any project requring the services of a building inspector will also require a structural engineer to sign off on plans that the building inspector cannot.

My footing goes down two feet for frost heave in this climate, and it's two feet wide. Multiply that by the perimeter of my building and that's a lot of concrete. I see the occasional bit of hand-wringing on-line about the piddling 5,6,7 % cement going into a contemporary rammed earth wall and I have to roll my eyes --that aint the least of it, son. 

Last spring I attended a rammed earth wall building workshop where a foot-thick, eight-foot long, five-foot high ( 6'x4'? my memory is hazy) block was rammed right on the bearing soil. No footing, no reinforcement, no damp-proofing, no roofing, and it is as crisp as the day it came out of the form after a long wet snowy winter. It hasn't fallen over and crushed a child yet either, though you can bet I will tell you all about it should that come to pass.

All that to say, this drawing might be on the excessive side of things when it comes to footings. I think more permitting officials and allied tradesmen should consider the Chew Kee Store and its walls that simply start two feet below grade, no concrete footing, cement stabilizer, steel reinforcement or damp-proofing barrier necessary, in Northern California, where they invented earthquakes.

My engineer specified rebar every two feet in each direction, which didn't seem excessive after the West coast projects I have seen (every sixteen inches, now that's a bit of a pain.) I wonder, though, if these walls would last longer (like, hundreds of years longer) without rebar in them. What if we are building walls that only last 500 years instead of 5,000?

I hired Blah Blah Engineering because when I spoke with Mr Blah he said, "Oh yes I'd love to do something with rammed earth, I studied it in the 70s and have even drawn up plans in the recent past." That is exactly the kind of confidence you are looking for in an engineer. You don't want a worrywort or someone unwilling to research. Otherwise, if you are in Seismic Zone 3 or higher and are looking for an affordable eco-building system, you might want to consider living on a boat or felting yourself a giant nest. By the time the permitting officials are done with you, all your money will be spent on insane re-inforcement schedules and giant concrete footings. And permitting officials.

This drawing and the rest of my plans were drawn by the incomparable Marshall Witzel at Aztec Drafting, who is a peach and you can tell him I said so.