Pushing The Envelope at the Ontario Natural Building Conference

The Ontario Natural Building Coalition’s annual conference took place this year from May 3rd to 7th 2022. For the third year in a row this conference was all-online. As a finale to the conference, Ana Gascon Marco and Clair Beach led a panel discussion titled “Pushing the Envelope of Natural Building.” Five men in Canada from all different categories of the construction industry talked about their expertise and recent work. The ONBC has generously made this panel and Chris Magwood’s BEAM presentation from the conference free to view on YouTube, and we highly recommend watching all that you can. 

Tim Krahn, assisted by Jamie McCulloch, gave a presentation on some of the history of Stabilized Rammed Earth (SRE) and its application today with examples from a recent project that Building Alternatives Engineering, Tim’s engineering firm, is working on. Tim was the first to admit that rammed earth in the form he was presenting is “for wealthy people who like how it looks” despite its centuries old practice across the globe. Tim gave a timeline of rammed earth from the great wall of China all the way to its current day code designations in Canada today. With a high concrete content SRE should follow the Design of Concrete Structures CSA A23.3, and with a low concrete content a third of the total or less, it should follow the Design of Masonry Structures CSA S304.1. Tim bemoaned the state of cultural values and building codes and standards of Canada with their shortsightedness. The fact that it’s illegal to build how they built “the manhattan of the desert” 700 years ago. That you cannot legally include maintenance into the design of your structures. Raw earth structures can and have lasted millenia, but only with regular maintenance. Canadian engineering code only allows you to design a building that everyone can immediately walk away from for the next 30 years. Upon questioning, Tim and Jamie talked about the viability of rammed earth at high rises, and an exciting new 2’x’4’x8′ rammed earth block product in development by Jeremy Maharis which uses excavated material from all over the greater  Toronto area.

Paul Dowset gave a great presentation on four draft sets of roof, wall, and foundation details that he and the Ontario Association of Architects are developing to include in the next Ontario Building Code. This is a great example of simple alternatives that most standard construction could turn to and become much lower impact and lower carbon. Of particular interest was the preserved wood foundations, which can be a code-approved all wood foundation option. He followed up these section diagrams with a deeper analysis of some structural, and each of the insulation materials that he and the association of architects had chosen, with their benefits and any of their hidden toxic chemical components as well. These included insulation materials included stone wool, cellulose, wood fiber, bio-based ICFs, and preserved wood foundations.

Jeremy Clarke of Simple Life Homes had even more wall section goodness with his presentation on their prefabricated panelized system. Jeremy had started this journey working on a retrofit project, and after a course at the Endeavor Centre he started his own company and eventually turned to prefabrication. Simple Life Homes is in a sense a Design for Manufacturing Ability (DFMA) company. They work with owners and designers to model and panelize a home design using their panelizing system which uses bio based materials, no concrete and no foam.

Aaron Waldt, of 475 Building Supply, gave a great granular presentation on some of the specifics that previous presentations had missed. He talked through some of the tapes, meshes, and membranes that are available through 475. He was also able to answer some questions from the previous presentation about Canada’s potential for a wood fiber mill, particularly that one will potentially be operating in Canada by the end of 2023. Aaron mentioned at the end the Contiga PV fiberglass mesh dperforms well in straw bale applications with a plaster finish.