Peter’s Concrete Block Dome

Peter Roberts has been building a unique dome structure in the woods and is sharing it with us. I discovered Peter when he posted a picture on the Tiny House Blog’s Facebook page.

Peter’s inspiration came from throwing giant pots. Peter was throwing large pots, and they became architectural, it prompted him to investigate ceramic houses, this led to the masonry system you see in these pictures.

Peter graduated from the NYS College of Ceramics at Alfred University with a degree in Masonry Science.  Peter combined his experiences in Fine Art and Ceramic Engineering.  This masonry system was identified as a Cutting Edge Technology by the American Concrete Institute.  These blocks can be made on any production block machine, either Besser or Columbia.

Peter has also worked with the Vocational School of Masonry at Alfred State College, located in Wellsville, NY.

These are some details of a masonry cupola Peter is building atop a concrete block dome.  The cupola will have a glass block dome on top of it.  The cupola weighs over 6 tons, indicating the strength of the concrete block dome.

Here’s an interior view of the block dome, with cupola being built in center.

Interior view of one of the domes.  Loft is arranged as a yin yang between loft and negative space, keeps a sense of openness.

These domes are in the forest, and Peter get lots of wildlife.  One night a bear tried to enter, you can see what he did to the door.

23 Comments Peter’s Concrete Block Dome

  1. Sue Goetschius

    Peter Roberts does not have a degree in masonry science. There is no such major at Alfred University. We offered BS, MS and Ph.D. degrees in ceramic engineering and materials science, as well as BS and MS degrees in biomedical materials science engineering and glass science engineering through the Kazuo Inamori School of Engineering, and a range of fine arts programs through the School of Art & Design.

    Reply
  2. Sue Goetschius

    I stand corrected: Peter does indeed have a degree in “masonry science.” It was a individually designed major, one that allowed him to take course work in many different disciplines. He’s probably the only AU graduate who can claim such a degree!

    Reply
    1. Lara Davis

      Dear Sue (long time no hear!),

      Maybe Peter has a degree in “masonry science” from Alfred…
      but he is still on his blog stealing the work of other experts in the field of masonry engineering, and not siting their work. And at that, stealing the work of other past Alfred grads such as myself. Maybe I didn’t get the only “masonry science” degree from Alfred – I got mine from MIT. And at that little school there are hard penalties for pilfering people’s research.

      Peter – please correct this pronto, and site my work at that of Auroville earth institute on your blog. I wrote this reasonably on the blog post, and you erased it. Now I am getting really annoyed.

      http://masonrydesign.blogspot.in/2012/01/interlocking-triangular-block-and-shell.html?showComment=1337164815823

      http://www.sudu1construction.wordpress.com

      Lara Davis, phd candidate
      ETH Zürich

      Reply
      1. Peter Roberts

        Hello Lara,

        I have tried repeatedly to contact you, in an effort to correct having cited your work without reference. I sincerely apologize for this greivous error and grave mistake I committed! I had a message to this effect up for several months, asking you to let me know which picture I improperly used. I have tried to fix this, and never heard from you. I did not see your comment here until today; I do not check this old blog entry regularly at all, it is not my blog. I have removed the pictures from the blog entry which you cited. I offer you a sincere apology. I did not think showing a simple catenary thrust line was so egregious: I am mistaken. I do in fact have a degree in Masonry Science, I studied cement science under Dr. Amarakoon. I will never “site” your work again, rest assured. Again, I apologize.

        Reply
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  4. Steve Hathaway

    As the bear door picture indicates, this house looks very able to withstand huffing and puffing and so on.

    –and I love the look of the interior; struck me as sort of North African, somehow.

    But I’m curious–perhaps a mundane detail, how are the shingles attached?

    Reply
    1. Pete Roberts

      The shingles are attached with roofing nails. There are furring strips over the block. The outside of the block is insulated with blueboard, to maximize the thermal mass benefits of the material. Insulation was then covered with board & batten.

      Reply
  5. Steve Hathaway

    Got a further question–was the original plan to have triangular glass blocks in the dome? That would’ve been very cool–and it seems like that was the case from some pics.

    If so, why did that not work out?

    Reply
    1. Pete Roberts

      Currently I have groups of engineering students working on making glass blocks. I have a more advanced interlocking system, which is shown on my facebook page under the photo file “block design”

      http://www.facebook.com/inbox/?tid=244897934209#/album.php?aid=25122&id=1136529319

      These particular blocks were used to build a high efficiency gas-fired kiln under a grant by the New York State Energy Research & Development Authority (NYSERDA).

      The glass blocks will be done using this system. These blocks can also be woven together with tensile elements, e.g., steel cable. The steel cable is located along the abutting edges of the block.

      The first dome I made initially had plexiglas in the holes which you see. (The second dome has those holes filled with concrete.) The plexiglas did not weather well, so I am finishing the outside with shingles.

      Concrete block machines produce a block every few seconds. A larger machine (6-at-a-time) produces a block every second.

      The blocks allow for conjugate shearing, the means by which ceramics fail under compression. Except the structure is “pre-fractured” so there is no failure; blocks are allowed to move to accomodate stress. Strain relieves stress, and gravity is the restoring force. The system is very tough and durable – resistant to crack propagation. It takes a very high load to make the blocks move at all: under tornado, hurricane, earthquake or avalanche conditions. This is an incredibly strong system.

      Blocks cost under $2 each, so a structure can be assembled for around $600 in block cost.

      For scaffolding, a bladder is inflated inside, blocks are laid, and the bladder deflated and removed.

      Reply
  6. Michelle Spencer

    I dig this hot sculptural home! Were kilns found to be successful with the block? Would maybe like to build a kiln with this system. Do you have a design printed to sell? What’s the scoop on that?

    Reply
    1. Pete Roberts

      The kiln was very efficient and responsive to any adjustment. I used 3 forced-air burners, creating a swirling vortex, resulting in a longer flame path and more complete combustion within the firing space. It was 38% more efficient than a conventional rectangular kiln; I built a conventional kiln (the same size, volume) for comparison.

      Currently I am having a new set of steel molds made for a kiln system. It will be built as a complete sphere. I’m probably one year away from having that available. Prototype work takes time!

      My designs are patented. I have several US patents on this. If you want to use the design, you can, but just don’t sell it.

      Here’s one of the patents:

      http://www.google.com/patents/about?id=1vQAAAAAEBAJ&dq=polyceramics+block

      Figures 58-62 show how cylinder blocks are used to make right-angle arches which intersect into a larger dome, this is pretty interesting. Lots of design flexibility and different ways to configure the system.

      Reply
    1. Pete Roberts

      Yes, built with a permit, as an experimental structure. This block system does not meet current code definitions for concrete block.

      Regular (rectangular) concrete block, used to build vertical walls, has the weak side in the lateral direction (facing outside). FEMA tests block walls by basically shooting a 2″ x 4″ through a cannon. This method just pokes holes through regular concrete block walls. The block system I’m working on has the strong side (axis of compression when blocks are made) facing the outside. As a result this system is several times stronger and resistant to lateral forces such as FEMA testing.

      Relevant terms (for which this system does not lie within the definitions) are found in American Concrete Institute’s codes 530 – 530.1

      http://aec.ihs.com/document/abstract/JWSMHBAAAAAAAAAA

      Reply
  7. Arlos

    Pete, I love the potential of the blocks but the overall building scares the hell out of me since I look at this with eyes here in California where quakes are a factoid of life. and a 6 ton dead load above my head is not heart warming in the least.
    This process does offer promise especially if material like papercrete hybrids are used in 5/8 domes or elements made from FRP?
    Concrete is becoming expensive and having designed and built a cement from seawater pilot plant two years ago, it is only going to become more expensive as companies like CEMEX reduce sites across the country.

    Reply
    1. Pete Roberts

      Hi Arlos,

      This system is designed especially for the loading involved in earthquakes, hurricanes, tornadoes, etc. For these applications steel cable is woven between blocks: the block design used is shown in the pictures for the kiln blocks (see message 8, above). The cable goes between the half-diamond key & keyway, where there is a straight line-of-sight. This provides an exceptionally strong configuration. This allows blocks to move around vis-a-vis conjugate shearing.

      By removing the bottom tier of blocks, you get a 5/8 dome. I wanted that extra space, so mine are full hemispheres.

      Cement is indeed getting more expensive, and its production is a major contributor to greenhouse gasses. On the very bright side, scientists just recently discovered the basic chemical nature of cement, referred to as “the DNA of cement” which holds great promise for finding new and better ways to make cement in an environmental manner.

      Here’s an article about this important breakthrough:

      http://blog.taragana.com/health/2009/09/10/scientists-decode-the-dna-of-cement-11669/

      Papercrete and FRP are also attractive options. I was looking at block manufacturing methods and materials for this system because it is a huge industry (over 6 billion blocks per year in the US) and I want to use existing infrastructure to provide a greatly improved building system. The key is to have a design which can release from a two-piece mold with no undercut, or negative draft. I have achieved this through a high level of symmetry, using the key and keyway system. This design also lends itself ideally to conjugate shearing.

      Any weight placed on the roof of this system actually makes it stronger. The 6 tons of dead weight shown from the massive brick cupola increases the compressive force on the blocks by (at most) 4 pounds per square inch; the blocks are rated at 4,000 psi compressive strength.

      There will be lots more coming in the future on this system. Please let me know if I can answer any other questions, and thanks very much for your interest. It makes for a cozy little tiny house.

      Reply
    1. Pete Roberts

      That’s a tough question, because so much of it was done using materials I had on-hand. It also includes water (well), electric, natural gas, high-speed internet, (all underground conduit) septic system, leach field, and such. The block part is inexpensive though, under $1,000. Block was probably the cheapest part!

      Reply
  8. Alan

    Interesting design. Just one question, why shingle the roof when you could have used metal lath and mortar right over the block?

    Reply
    1. Pete Roberts

      Everything’s an experiment now, maybe I’ll do that on the next one. I have three of these domes to play with. I could also do cedar shake, or rubber, even thatch. I’m trying to use common methods and materials. Metal lath and mortar is a good idea though, Alan.

      Reply

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