research project

Panel Making

This week the Thermal Mass and Buoyancy Ventilation Research Team got to use the largest skill saw they’ve ever seen and we’ll tell you why!

In the technical workshop Sal last week, the team decided to narrow the number of materials they will test throughout the experimental cycle from four to two. The lucky two will be concrete and softwood! Concrete is often used as a thermal mass material while softwood is not which will make comparing the data collected from the separate experiments all the more interesting. The Optimal Tuning Theory calls for the thermal mass to be externally insulated which allows the thermal mass material to be much thinner than a typical thermal mass. Therefore, the concrete and wood need to be panelized.

The thermal properties of wood act most efficiently as a thermal mass when the cross grain is exposed to the air. This means that panelizing the softwood is more like creating giant cutting boards. To practice this process the team used 8″ x 8″ Cypress timbers and their matching 16″ diameter skill saw leftover from the Newbern Town Hall project. The team learned that 6″ x 6″ timbers would be ideal for their project, that way they can cut the cross-grain pieces in one cut with their 16″ skill saw without having to rip down the timber.

The concrete panels are far more straightforward, build a mold, pour the concrete, let it cure. However, the team has to think about how the panels would be attached to a larger structure. To solve this they cast PVC into the panel which will allow it to be screwed into a structure.

Voila! We have much refining to do of the panel making process, but the first two turned out well. We also have here a rendering of the habitable structural with the separate concrete and wood panel rooms. Our next step is to apply what we learned working with these materials to designing and building our first experiment. Thermal Mass and Buoyancy Ventilation Research Team out.

The Experimental Cycle

The team with the longest name possible is back this week diving deep into the science behind the Optimal Tuning Theory with its author, engineer, Sal Craig. Sal, along with his colleague, architect Kiel Moe at Mcgill University in Montreal, Canada, are our partners in the Thermal Mass and Buoyancy Ventilation Research Project. The team has weekly meetings via Skype with Sal and Kiel to discuss the project, but this week they had an in-depth technical workshop.

Behind our simple understanding of the Optimal Tuning Theory, there are very intricate scientific equations that Sal has written, solved, and published in his peer-reviewed paper, The optimal tuning, within carbon limits, of thermal mass in naturally ventilated buildings. Although the student team does not need to obtain an engineering degree to work on the project, it is important they grasp the basics so the project is truly a collaboration. They need to be able to have a conversation with Sal about the possibilities of the project instead of asking his permission. 

The team studied up for their technical session with Sal


Thankfully, Sal is a wonderful teacher and the students were able to reach a deeper understanding of the theory with him during their day-long technical workshop. Afterward, they were able to make a couple of important decisions about the project together one of which was defining the undergraduate phase of the project as an experimental cycle.

The experimental cycle will be comprised of testing the Optimal Tuning Theory at three different scales they are calling Desktop, Human, and Habitable. These scales are important because the theory is meant to be proportional. The Desktop experiment will resemble a small chimney made of thermal mass material, the Human scale experiment a full-sized thermal mass wall, and the Habitable experiment will be a full structure i.e. the pod where the interior walls will be entirely thermal mass. 

Livia with her beloved schedule

Defining the experimental cycle has allowed the team to start scheduling and setting deadlines, something Livia has been dying to do. Completing this cycle in the undergraduate phase of the project will allow freedom for the graduate phase. Thanks for tuning in!

And Suddenly, Floors!

Upon returning to Newbern, the team continued the metal theme and spent the first day back coating all of the metal elements of the pod with a clear lacquer finish to prevent weathering while maintaining the unfinished look of the metal. Then they made the switch back to working with wood.

With all of the wood for the floors prepped and ready to go, installing the floors was a simple and quick process. Of course, before the wood could be placed, the world’s most substantial termite shields had to be installed. The termite shields comprise of ¼” steel plate welded into a box and are designed to complement the massiveness of the mass timber and concrete foundations.

After the termite shields were siliconed in place, the wood for the floors was placed, a process which took about fifteen minutes. Then the wood was roughly aligned so that the threaded rods could be inserted. Once the rods were in place and lighted fastened, the wood received its final alignment. By far the most time consuming part of this process was tightening the threaded rods as, even with our preliminary tightening, the wood still had subtle warping and cupping that needed to be squished out. The floor installation overall took about five hours, four of which went into tightening the threaded rods.

Stay tuned for the rest of the pod coming after Christmas.

Building is getting serious,

The Fabulous Floor Folk

Soundtrack: Construction Site Song | The Kiboomers

Steel Fabrication

The steel for the spreader angles and plates has been delivered and the team has been working on fabricating those pieces. The plates and angles will run along the walls, floors, and ceilings edges in order to evenly spread the load throughout the wall/floor/ceiling when the threaded rods are tightened down. Each plate and angle has to be cleaned, holes torched, and then coated with a sealant to prevent weathering. Once the steel is finished, the team can begin processing the wood for the walls and ceilings using those plates and angles as templates. 

As the pod begins to become a reality, the issue of properly staging the construction process to be as efficient as possible is becoming an important topic. To that end, the team decided to fabricate the trusses before beginning to build the pods so that the roof can be immediately installed once the walls and ceiling are in place to prevent the wood from being exposed to the environment for any length of time. It is to this end that Jim Turnipseed and Turnipseed International have been extremely helpful in this process. Not only was all of the steel for the project donated but the team was also able to use Turnipseed International’s welding shop to fabricate the trusses and other steel elements of the project. It was a welcome break from the wood processing to learn about steel and how to weld.

The whole process only took about 5 days. The team spent the first two days cutting down all the members of the trusses, the purlins, the runners, and the plates. The next day, with the help of the men working at the shop, they laid out the truss design on the warehouse floor and welded together a jig. This allowed the team to easily slide the members of the truss in place then weld together each joint. 2 days later, 11 trusses were completed and transported back to Newbern!

Stay tuned for updates as the team returns to Newbern and puts this steel to good use!

Already missing the shop,

The Metalworking Massers

Soundtrack: Dirty Paws | Of Monsters and Men

Horizontal and Vertical Sock Tests

Wondering if the team still masquerades as scientists? Don’t worry, the science lives on. Throughout the construction process, the team has been running horizontal sock tests day and night; four tests a day, every day but Sundays! They have completed a series of small scale horizontal sock tests and are currently working on their first peer reviewed paper. This paper will present their findings on the suitability of wood for Breathing Walls, as well as their initial findings on their vertical sock tests.

Horizontal sock testing set up

Vertical sock testing is the next step in the testing series. As the team scales up the tests, a new variable is added. This series of tests will introduce buoyancy ventilation to the system rather than use forced air with the blower door fan. The sock, currently set up in the team’s living room, is an 8’ tall insulated cone with sensors at the top and bottom logging pressure, temperature, air flow, and humidity. They are currently calibrating this test and hope to finish up the series before Christmas! After that, they’ll move on to laminated panels and eventually to testing the full-size building currently in construction.

The team is off to the big city (Birmingham) again soon to trade off with the Horseshoe Hub Courtyard team in the metal shop. They’ll be taking a rare break from wood and fabricating trusses and other steel components, so stay tuned for updates.

Full of hot air,

The Testing Team

Soundtrack: The Scientist | Coldplay