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.
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.
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!
This just in: there’s is a big hole in the Thermal Mass and Buoyancy Ventilation Research Project site!
Thanks to C & T Excavation Inc. the TMBV Test Buildings have broken ground. Local and Rural Studio excavation efficiando, Tyler, completed the initial site grading and the foundation dig. Let’s take a look at how the TMBV team prepped the site for this momentous day.
Newbern’s Newest Crater
Before you can dig a hole, you’ve got to know where to dig! This is where the superheroes of construction, batter boards, come into play. Batter boards are quintessential for starting construction so they must be precise. To clarify, batter boards are temporary frames, set beyond the corners of planned groundwork at common elevations.
Typically, batter boards consist of two stakes driven into the ground with a horizontal member held between them. Next, once you’ve assembled and leveled the batter boards, you use construction string to “pull” layout lines. The layout lines are then secured to the batter boards. Layout lines cross the site either east to west or north to south, between batter boards, to indicate the foundation limits at their intersections. It’s important to note the elevation of the top of each batter board must match so when strings are pulled across the strings intersect.
The TMBV team pulled their first layout line west to east from the Supershed columns. From this line, all other layout lines are set. When all lines’ distances and intersections’ squareness are triple-checked, the team marked the initial grading limits on the ground with spray paint. The end result, with string crisscrossing about like laser beams, feels a bit like a scene from an action movie. Especially if you practice jumping over and rolling under the strings. But, of course, none of these very professional research graduate students took part in such conduct.
At the end of a long day pulling strings, the team marked their initial grading and detached all the layout lines from one side. The layout lines positions are marked on the batter boards so they can be put up and down as needed. Obviously, you can’t build with a bunch of strings in your way. After the initial site grading, the students re-pulled the strings which indicated the foundation limits, marked the corners, and Tyler began digging again. In about 6 hours time, Morrisette Campus had a brand new swimming pool and the TMBV team had a real project site.
In parallel with site groundwork, the TMBV team worked across campus on their mock-up. To mimic the SIPs walls of the test buildings, the mock-up uses 2″ x 12″ stud walls. Due to the angle of the roof and the chimneys, there was much mitering to complete and even more mitering math to figure out. The team built all the stud walls and are ready to assemble. All the especially funky parallelograms you see below are the chimney pieces. With the kit of parts complete, the team awaits columns to build upon.
Cooling Patio Design
True to the design-build spirit, the team is still designing as they’ve started building. The ground plane of the cooling patio was the subject of this week’s design charrette. The team has used, concrete side-walk pieces they intend on using as pavers. However, it is not decided yet how those pavers are arranged.
The team wants to eliminate any excessive cutting of the pavers, especially exact cutting, so they ruled out a linear pattern. They are pursuing a mosaic-like pattern that minimizes concrete cuts. However, without a full inventory of all the concrete pieces, it’s difficult to produce a realistic design. Therefore, in the coming weeks, the team will be taking stock of their recyclable materials. After this, they can start laying out patterns using a steer skid loader to move concrete pieces around.
Welcome to Winter
As mentioned in the Thermal Mass and Buoyancy Ventilation Research Project Team’s last blog post, the chill has rolled into Hale County. There is never a shortage of beautiful scenery in these parts as proven by these frosty silos. By next post the TMBV team hopes to have another gorgeous view for you; a freshly poured foundation! Here’s hoping and thanks for tuning in!
Live from a double-rainbow kissed Morrisette Campus, It’s the Thermal Mass and Buoyancy Ventilation Research Project team! Recently, as the chill rolls into Newbern, the students and faculty witnessed this heart-warming phenomenon. And if you came for the rainbows, you should stay for the structure. Hang tight to learn how the TMBVRP team is supporting the Test Buildings eight feet off the ground.
One more thing before we get on to the structure, a quick look at the Horseshoe Courtyard. During this semester the TMBV Research Project team has enjoyed working on the Horseshoe Courtyard site. Every Tuesday, project teammates Caleb and Claudia are wonderful and patient teachers to the TMBV team. The team certainly appreciates the construction experience and the time away from their computers. Go check out all of the beautiful work the Horseshoe Courtyard project team has done on their blog!
First, a quick reminder of how and why the Test Buildings are up on stilts. Because the Optimal Tuning System uses thermal mass to create airflow, the Test Buildings will expel cooled air. In the Summertime, that cooled air could be a benefit to more than just the Test Building dwellers. Therefore the Test Buildings design was lifted in order to create a Cooling Patio underneath. Here, anyone can enjoy an outpouring of chilled air. The team chose steel columns to do the heavy lifting to keep the focus of the space on the solid Downdraft Chimneys. As seen in previous blog posts, the column’s placement is dictated by the relationship to the Downdraft Chimney’s and the seating arrangement. However, the column arrangement can not just look good on paper and feel right in the mock-up, it’s got to actually, safely stand up.
Thankfully, structural engineer Joe Farruggia approved the column placement—now it was time to size the columns. Through a series of hand calculations, the team tested the stiffness of 3.5″ – 6.0″ diameter steel columns to see which ones could handle the weight of the pods. Then, Rowe took this work into Intercalc, an engineering software. Intercalce allowed him to test structural loads such as gravity loads, wind loads, live loads, and overturning forces. It turns out a 5″ O.D. steel column will be more than safe. Now, onto bracing!
Three of the four columns, per test building, are braced to eliminate excessive drift caused by wind loads on the tall faces of the buildings. Similarly, bracing the columns reduces possible deflection and improves stiffness. The column bracings, hidden in the berm walls surrounding the Cooling Patio, are 4″ x 4″ x 3/8″ steel angles. The six braced columns appear 5′ tall as they disappear into the berms while the other two are the full height of the occupiable space at 8′ tall. These taller, unbraced columns act as entrance markers.
Originally, the team believed a concrete ring beam foundation would be sufficient for fixing the steel columns, and thus the buildings, solidly to the ground. As seen in the drawing above, the ring beams would extend to catch bracing. However, the team needed to consider overturning moments, or overturning forces, due to the height and the aforementioned wind loads of the Test Buildings. Overturning moments are those applied moments, shears, and uplift forces that seek to cause the footing to become unstable and turn over. This means they needed to make sure the foundations were strong enough to keep the columns and bracing in the ground during bad storms.
Before these moments could be properly designed for, the team needed to do some soil testing. The quality, based on its compaction, of the soil is another factor in determining the necessary size, and strength, of the foundation. Jeff and Cory dug some holes and then used a penetrometer to test the soil. And who would have thought—the site has some pretty decent soil! Unfortunately, Jeff has been stuck in that hole for weeks… We miss you Jeff!
To counteract the overturning forces, the foundation changed from a ring beam to a buried slab foundation which increases its weight. Each Test Building will have its own foundation. The slab foundations secure all columns and bracing to each other as well as the ground. Below are currents drawings of the foundation, column location, and bracing connections.
The Thermal Mass and Buoyancy Ventilation team will be jumping into drainage and ground material master planning next. Translating research into design into construction has been an arduous journey. However, the pay off will be worth it when designers anywhere can use the Optimal Tuning Strategy to make building materials work as air conditioners. Thanks for reading and stay tuned!
Yep! We’ve been here the whole semester! It’s time, dear reader, to spill the beans on our comings and goings, our hopes and dreams, our successes and failures, and our project. Come on in, make yourself comfortable. Pour a hot cup of tea, listen to our story. The tale of Rev. Walker’s Home project team is only the beginning.
Our journey, as 5th-year Rural Studio students, begins in Hale County, in August. The county is a sparsely populated, tapering rectangle in West-central Alabama. The foothills of the Appalachian Mountains find their end in the northeast corner of the county. The densely forested rolling hills of the northeast quickly give way to the astonishingly flat plains known as the “Black Belt.” This area is named for the rich soil that is optimal for cultivation. Greensboro is the centrally located county seat populated by 2,291 residents. Ten miles south of Greensboro on Alabama Highway 61 is Newbern, home to Rural Studio headquarters. In Newbern, the beloved Red Barn, can be found. Red Barn, the workspace where the us Rural Studio students put pens to paper. We spend a lot of time in Red Barn, and its leaky windows and visibly tilted walls endear us to it.
The beginning of each semester at Rural Studio is marked by “neck-downs.” Neck-downs defines a time dedicated to maintenance of studio grounds, small projects, and the assistance of teams whose projects are in the construction phase. This Fall, neck-downs included repairing facilities at Perry Lakes Park in neighboring Perry County, assisting the Horseshoe Hub Courtyard team on their site, and taking care of odds-and-ends on Morrissette Campus. Typically, neck-downs lasts one week. This year, it was extended and incorporated into our studio schedule. Some of the work is ongoing and gives us moments throughout the week to put away the pencil and pull out the shovel. “healthy bodies, healthy minds” our captain, Andrew Freear, likes to say.
Simultaneously with the site-work around the area, our entire 5th-year student cadre worked to further the exploration into post-frame structures and formulate a thesis. The idea, first proposed by the 2020-2021 outreach master’s team, uses a post-frame structure to reduce construction cost and timeline. Our charge is to take the system and the efforts of the outreach team and expand on it in two didactic ways. We started by touring past projects around the county, exploring ancient barn structures, and documenting local building trends.
Taking note of the trend in the area to expand one’s home as means and needs allow, the 5th-year thesis project’s has developed into two expansion approaches. One strategy is a home underneath a large roof, provided by a post-frame structure, on an expansive foundation that will enable an owner to quickly add enclosure without compromising structure. This is Rev. Walker’s Home strategy. The other is a home that encourages interior expansion and customization by bringing the post frame structure into the envelope of the home. This is the Myers’ Home strategy.
Our team is designing and will be building Rev. Walker’s Home. This team was chosen in an age-old ritual, of which here I will not tell. We like to think of ourselves as hardworking, strong-willed, opinionated individuals who can even be considered fun. I am, of course, the leader of this motley crew. My name is Taterhead the Cat. I enjoy drooling on unexpecting scratch-givers and surveying my land, which Rev. Walker’s Home will occupy. I am a skilled delegator. My leadership style is strict yet fair, and I expect only the best work from my team.
Here’s the rest of them: Becca, George, Paul and Addie. Becca has a three-legged cat named Rocko and is the maker of the fantastic yellow hats seen above. George is just a dude with no distinct personality traits. (Editor’s note: This is an unfair representation of George, a very impassioned individual.) Paul likes to spend his time collecting objects from the ground. He likes sheds. Addie has a dog named Pat. She drives the biggest truck in Hale County.
It will not be an easy path to walk with this lot. Their refusals of scratch-giving will be met with reprimand. But rest easy, dear reader, for I am at the helm and will guide the ship to clear waters. My hope for this journal is to provide a clear account of our journey to the edge and back, and to bring you along with us.
The 2020-2021 5th-year students are ready for their introduction! They may have been off the radar so far this semester, but they are working the days away. The 2020-2021 Rural Studio thesis program began with eight students and several weeks of “neck down” work, the kind that uses everything but your head! This meant performing maintenance at Morrisette Campus and the Red Barn, lending a hand at Horseshoe Courtyard, and rebuilding park structures at Perry Lakes Park.
Thanks to the pandemic precautions being taken by all Rural Studio members, the 5th-year project teams are able to work face-to-masked face this semester. They’ve been working on site, in studio, and on the farm safely and gratefully. Presentations and critiques are all al fresco, but the work is just as hard, coffee as strong, and spirits as high.
While completing the “neck down” site work, the 5th-year students began their thesis research. Their thesis projects are to design and build two homes using a post frame structural system. This post frame strategy was first introduced to the studio by last year’s Master’s Outreach Team in their 2020 20K Home. The teams will be building for the clients of Reggie’s Home project team and the 2020 20K project team, both projects which were paused due to the COVID-19 pandemic. The team of eight is studying how to take full advantage of the pole barn frame. With several thesis research presentations on deck, the team began the routine of site work by day and studio by night. As the pros say, “healthy body, healthy mind!”
Meet the post frame structural system, sometimes known as a pole barn. It’s a kit of parts purchased as a complete package from one manufacturer or multiple suppliers. In both cases, the post frame system is made up of columns, trusses, roofing material, and often a concrete slab. The order of construction allows the roof to go up first. This is the opposite of traditional stick frame construction, how many past Rural Studio residential projects are built. In stick framing, exterior and interior framed walls are raised prior to installing trusses and roof metal. In this case, inclement weather means a losing a valuable day building on site if the roof has not been constructed yet.
Post frame gives the team the ability to raise the roof first, the initial structure being trusses and roofing material on columns over a now-covered slab. Exterior and interior walls as well as cladding and utilities come after the roof. This means come spring and all its rain, build days can go on through what would normally be weather delays. The 5th-years were able to visit one of these structures mid-build in a visit to one not too far from their home base.
But post frame is not all that’s on the mind. The group of eight has been researching, documenting, and analyzing homes in the area, including 20K Homes. They are studying how 20K Homes have expanded and adapted over time. This led to two approaches responding to rural expansion coupled with a post frame structure. One is a home under a separate roof, expanding outward beneath it, explored in Rev. Walker’s Home. The other is a home focused on interiorized expansion within the envelope of the post frame system, what will be Myer’s Home.
John Forney from Birmingham and Mike Newman out of Chicago were the first outside voices to weigh in this semester. Their feedback on the first public explanation of project goals helped them shape their arguments in the time after. Since then they’ve been developing the “why?” of the post frame structure and the “how” of our two expansion strategies. The former is that due to the speed of initial post frame construction, labor costs reduce the budget by 10% overall. The latter is in constant progress.
Following these reviews, teams and projects were chosen in traditional, mystic Rural Studio Fashion. With a full review schedule this fall of familiar faces including Julie Eizenberg, Tod Williams, Billie Tsien, Marlon Blackwell, Jake LaBarre, and a November Stress Test date, the teams jumped in headfirst.
Here they go, Myers’ Home team: Riley Boles, Madeline Ray, Robbin Reese, and Judith Seaman. They will be exploring the post frame home through interiorized, upward expansion. You will get to know the new kids on the block as they journey to a new frontier—the attic!