Monday, July 29, 2013

Move to Ferro-Cement

Before we arrived on Mfangano Island we were under the assumption that we were building a "test structure" - a full scale but still usable, prototype that would be used to demonstrate the potential of the tile vaulting technique. We agreed that a vault covering a space that was about 10ft x 10ft was a challenge, but manageable despite the other challenges we were taking up. As we began talking with the Ekialo Kiona Radio staff in early June we quickly realized that 10x10 was far too small to accommodate all of the radio operations. During the schematic design phase (which lasted only a few days) the square footage of the building more than tripled. Nevertheless, we pushed forward with full confidence and immediately began working toward this design.

Things ran smoothly up until point where we began working on the tile vault. As was documented in the last blog post, we experienced catastrophic failures a few days into the build. After much deliberation we determined that there were a number of factors that lead to these collapses: lack of experience of the tilers, strength of the tiles versus the strength of the plaster, and the overall size of the vault. Although we have our own academic and research-based goals in mind with this project, the truth is we are also intending to construct a building to be used by a hugely successful community-based radio station that has been in operation for almost a year.

It is our responsibility to provide this community with a building they are able to finish constructing and use safely once it is complete. As a "Plan B" to this project we have known (although never officially said) that ferro-cement was a viable alternative to tile vaulting since the technique has existed and been practiced on Mfangano for a little over four years.

So, a collective decision was made to continue pursuing the design for the roof using ferro-cement. While it is disappointing in terms of the pursuit of research in tile vaulting, we still feel accomplished a lot. We've succeeded in using earth construction in the structural walls, we've managed to pass on new principles of structure and complex geometry that will still be accomplished in the ferro roof. Although we are missing is the tiling technique, there are many tiles that remain that will be used by construction team on Mfangano for practice and experimentation after we're gone.

photo courtesy of OHR