The Breathing Wall Mass Timber Research Project Team, alongside collaborators and colleagues Sal Craig, Kiel Moe, David Kennedy and Rural Studio’s own Andrew Freear, have officially published their work! The original research paper, entitled “The Design of Mass Timber Panels as Heat-Exchangers (Dynamic Insulation)” was published in the Frontiers in Built Environment journal. A culmination of two years of investigation and experimentation (see the blog here for more info), the article shows how to optimize mass timber panels as heat-exchangers and suggests how to pair panels with buoyancy ventilation.
The Breathing Wall Mass Timber Team and Sal Craig; the wonderful collaboration
Why is that important? The building industry is currently responsible for roughly 40% of global greenhouse gas emissions, with a significant portion originating from the production of construction materials like concrete and steel. Mitigating this climate crisis requires a fundamental shift in what and how we build. Mass timber heat-exchangers offer a potential alternative. Mass timber products are naturally carbon sequestering, and building responsibly with timber has the potential to store carbon in the global carbon sink of new building stocks. Designing panels to be multifunctional provides the opportunity to further multiply savings by suggesting how to eliminate fossil-intensive insulation while simplifying ventilation systems.
How the Mass Timber Breathing Wall works
Mass Timber heat exchangers aren’t the only alternative – thermal mass is another example of this ‘radical integration’ – but the Mass Breathers and Co are excited to contribute to the conversation, and hope you will too! The article and data are all in the Creative Commons (thank you to MSSI for funding the license), and research is ever ongoing!
The Breathing Wall Mass Timber Research Project Team: Jake, Fergie, Preston and Anna
Exciting news from Hale County: the Breathing Wall Mass Timber Research Project (BWMT) test building construction is complete! Last week Fergie and Preston finalized the construction of two mass timber test buildings on Rural Studio’s campus. These test buildings will be used in the future for research on the breathing wall, thermal mass, and mass timber. The team is also in the peer review process for their scientific paper on their small-scale experiments. It’s been a busy two years!
As a quick update, these two mass timber buildings are the result of two years of design and experimentation on mass timber systems and their potential integration with breathing wall technology. The floors, walls, and ceilings are all dry-stacked timber compressed with threaded rods to ensure an air-tight envelope. All of the steel components were designed and fabricated to facilitate the BWMT experiment: a steel roof acts an umbrella to protect against solar radiation and wind-driven rain; doors are hung from the top on the exterior to adjust to expanding timber; and steel plates and angles spread pressure from the threaded rods evenly through the timber. On the interior, flexible loft spaces are accompanied by fabricated railings and ladders, with a simple conduit carrying all electrical and lighting. The entire project was designed with flexibility in mind, so they can be used for future experimentation. The goal isn’t that these buildings are precious, but that they’re useful.
The past two years have definitely been a learning experience – doing scientific research at an architecture school was difficult at times, but the tension between the two really propelled the team and the project. The team learned to leverage the scientific aspect to inform their architectural decisions and to use their architectural knowledge to keep the research grounded. In the end, the design was stronger because it was backed by actual research; science and architecture can and should go together.
The team would like to thank the many reviewers and supporters who helped further this project for the past two years. Thank you to the Rural Studio faculty and staff, particularly Andrew Freear and Steve Long. Thank you to all who donated gifts, materials, and time. Thank you to the team’s studiomates, friends, and family for the constant support. Thank you to the Newbern community for welcoming the team in and taking them under their wings. And huge thank you to Salmaan Craig and Kiel Moe at McGill University and David Kennedy at Auburn University who volunteered their time each week to invest in and further this research.
Rural Studio is a place filled with magic and the team was extremely thankful to have been a small part of it for the past two years. The team served not only as students but community members, scientists, buildings, chefs, and farmers (to name a few.) They gained an understanding of the importance of being a part of the place and the community. All four team members are committed to taking what was learned in and out of the classroom forward with them as they move on from Hale County.
As for the team, Jake has been in New Orleans researching mass timber as a Research Fellow for Eskew+Dumez+Ripple. Anna is pursuing her PhD at McGill University furthering the study of the Breathing Wall. Fergie and Preston are moving to the mountains of Colorado to chase some design-build dreams. The team looks forward to the many visits back to Hale County and Rural Studio. That’s a wrap!
A lot has been happening here on the ground with the Breathing Wall Mass Timber Research Project team. The team said goodbye to Anna Halepaska a few weeks ago as she made her way to McGill University to pursue her PhD in architecture under Salmaan Craig, a main collaborator on this two-year research project. Huge congratulations to her and her future in research!
Fergie and Preston are here at Rural Studio finishing up the construction of the breathing wall mass timber test buildings. The roof is nearly complete! The majority of the roof metal has been screwed down to the purlins and the two teammates are finishing up the south end this week. The south side acts as a hip roof for water drainage while the north side is an open, angled gable end.
Last week the team (with the help of a few of our new 5th-years on campus!) poured concrete footings and set the posts for the metal grate walkway. Once the angles were welded to the post, the walkway was put in place. Borrowing a few details from the Perry Lakes projects, the stairs were welded in place to complete the full walkway. Next up, doors!
Yet again, the team used an older Rural Studio project, Newbern Town Hall, as a precedent for the door detail. The steel angle frame is attached to the exterior wall only at the top while the side clips keep the door frame flush but are not fastened directly to the frame. Wood expands and contracts over time so this detail gives the door an opportunity to expand and contract with the wood, riding up and down the exterior wall along the clips. This also minimizes thermal bridging around the opening. Keep an eye out for the final door install!
The to-do list is getting shorter by the day. The team will be installing the doors and running the electrical next week to wrap up the construction of both test buildings. Stay tuned for an update on the team’s research paper and the peer review process!
The Mass Timber Breathing Wall Research team has been in quarantine for the past several months, but they’ve kept themselves busy. The summer was spent finishing up experiments, carefully documenting data, and finally writing and submitting a paper on their research to a scientific journal for peer review. The team is currently waiting to hear back from the journal, but keep an eye out for a future post with details!
Now that a new semester has begun, the team is back on site (following COVID-safe protocols!) and finishing up the two mass timber test buildings on Morrisette campus. After sitting under a tarp for a few months, the pods needed a little TLC. But one of the benefits of stacked timber construction using threaded rods is the ability to take the building apart again – which is great for test buildings that may need to be altered in the future. The team (plus our volunteer, honorary teammate, and Rural Studio graduate student, Charlie Firestone) unstacked, re-braced, and re-stacked the walls and ceilings for both pods over the course of two weeks.
Once all of the wood was up, steel plates and angles were threaded on along the ceiling and floor to evenly distribute force from the threaded rods. The walls were tightened down, and lag screws driven through the thinner North and South walls to pull the corners tight. A layer of sill seal (a compressible gasket) in all of the joints ensures that any gaps or irregularities are sealed. Finally, a couple coats of spar urethane sealant protects the pine from moisture and mildew.
Switching material palettes for the roof, a steel space-frame spans over and between the two timber ‘boxes’ to support the corrugated metal roof. The team fabricated all of their trusses last year in Birmingham (thanks again to Turnipseed International and the guys at the shop!), so they were ready to go up as soon as the wood was sealed. It was a long morning in the Hale County heat, but with the help of Prof. Steve Long and the Bobcat everything went up smoothly. Purlins were welded in place, and corrugated sheet metal will be going up soon!
Since the days get so hot here in the summer, afternoons have been spent doing prep work for the next day and finishing interior details. The lofts (which are centered over the space to prevent asymmetric airflow) were installed, resting on ledgers which run along the east and west structural walls. Railings and ladders – fabricated from 1” steel tubes – were screwed in place.
The last few tasks are installing the roof metal, doors, a metal grate walkway that runs along the front of the two buildings for access, and lighting and electrical. Stay tuned for updates on the paper, and finishing details on the two test buildings!
Unfortunately, due to COVID-19, Rural Studio had to cancel the Pig Roast celebration hosted at the end of each spring semester to acknowledge the work happening in Newbern. To conclude the team’s two years of research, the team presented to a wide range of reviewers in a “Zoom Roast.” This celebration/critical review allowed the team to share their work as well as receive feedback on how to continue moving forward. Thank you to the Rural Studio faculty, Auburn University faculty, and our project collaborators from McGill University and Auburn University for spending the morning reviewing the project on Zoom. Also a huge thank you to Michael Jemtrud from McGill University, Z Smith from Eskew Dumez Ripple, Billie Faircloth from Kieran TImberlake, and Jonathan Grinham from the GSD at Harvard University for coming in as guest reviewers to critique the research project.
Zoom Roast with reviews from Auburn University, Rural Studio, McGill University, Harvard University, New Orleans, and Philadelphia.
Overview of experiments the team conducted in their two year research project.
The team is currently working on a draft of their first peer reviewed paper (!!!) to be published in Energy and Buildings. The “zoom roast” was an opportunity to analyze the experimental set ups before beginning the peer review process. The team has been working closely with Salmaan Craig in the past few months to finalize a draft focusing on three experiments the team completed in the past year. The paper explores a method of integrating ventilation and heating into a mass timber envelope, allowing for a mono-material building that is able to sequester carbon and reduce greenhouse gases while also reducing the need for mechanical ventilation systems. The experiments in the paper lays out 1) how to optimize panel geometry and identify the design space for this system, 2) how the system could be synchronized with natural ventilation flows to obviate conventional HVAC, and 3) how transient behaviors affect the system.
Overview of the Breathing Wall system in a mass timber construction.
Set up for Experiment I: Forced Air
Set up for Experiment II: Buoyancy Ventilation
Set up for Experiment III: Forced Air
The team is also working on writing up the results and testing method for the thermal conductivity testing they completed in the engineering lab at Auburn University to be published in an architectural journal.
The team tested a variety of pine samples measuring the thermal conductivity of each.
Stay tuned for links to both of these papers once published and available to the public!
