recycled materials

The Great Walls of Newbern

July 8, 2021

Live from within the newly completed Cooling Porch retaining walls, it’s the Thermal Mass & Buoyancy Ventilation Research project team! We’ll take you through the evolution of both north and south wall and all the earthwork in between. If you stay tuned ’till the end you’ll see Cory’s latest artistic venture; a short film titled, “Le Grevier.”

Backfilling and adding the final course to the north wall

North Wall: Complete!

After laying and leveling the dry-stacked concrete highway barriers, the team backfilled gravel and earth against the wall. Directly behind the walls are drains that are wrapped in landscape fabric and covered with gravel. This protects the drains from getting clogged with Hale County Clay. Behind the gravel, the team piled and compacted earth. They are reusing the dirt excavated for the building foundations. This process repeats for each course, refilling the initial dig. The Cooling Porch is still a hole in the ground, but it’s becoming a far more precise hole in the ground.

completing and leveling north wall course 3

Tamping over damp dirt and clay is a struggle

Voila! The joints, pattern, color, and textures of the north wall turned out fantastic. The team was astonished by the uniformity of the wall and the blending of the different blocks despite using reclaimed materials. On to the south wall!

South Wall: Complete!

Beginning the 1st course of the south wall and taking down the batter boards!

The process of constructing the south wall was essentially the same as the north wall. Small concrete footings were poured wherever the retaining wall went off the building foundations. The team also completed the installation of the drainage. The space began to form right in front of their eyes!

Fully Blocked

The team feels the space looks exactly as they drew it–which is both slightly surprising and super satisfying. All the measuring, drafting, and double-checking produced a beautiful pit. And, bonus, the reuse of materials is a surefire way to build with the environment in mind and luckily these concrete highway barriers turned out to be the perfect durable, stackable material. The backfill and dug-out stairs makes getting around site a whole lot easier. It’s all coming together!

Thanks for following the progress of the soon-to-be chilly demonstration space! Stay tuned for SIPs construction and laying the ground surface in the Cooling Porch. Now, for your enjoyment, follow the life of a scoop of gravel in Cory’s feature film, “Le Grevier.”

Le Gravier

Le Grevier: Directed by Cory Subasic starring Wheelbarrow, Shovel, Bobcat, and Gravel with a special appearance by Livia Barrett as “Gravel Girl.”

Tags: concrete, Cooling Porch, earthwork, masonry, recycled materials, research, research project, retaining wall, Thermal Mass and Buoyancy Ventilation

It’s Retainin’ Men (and Livia)

June 8, 2021

Live from the Cooling Porch, it’s the Thermal Mass & Buoyancy Ventilation Research Project team! Recently, the students focused on the demonstration space beneath the Test Buildings known as the Cooling Porch. Specifically, they began constructing the retaining walls, made out of old concrete highway barriers, which allow the space to be sunken and trap all the cool air rushing out of the Test Buildings. Let’s get into it!

Mock it up!

To test the structural rigidity, building method, and pattern of the varied in size concrete blocks, the students landed on tying the blocks into the packed earth behind the wall by placing pieces of expanded metal mesh between the block courses. The blocks are dry-stacked, using only their weight and the mesh to stay in place.

connected block to earth with expanded metal mesh

The expanded metal mesh makes the wall sturdier, but also allows the students to slip the straps theyre using to move the blocks out after placement without untying the straps from the Bobcat forks.

reclaimed material palette and full coursing

The students originally planned on using concrete blocks as the benches, but they could not find enough reclaimed materials. The solution? Insert flat steel between the concrete block courses which can hold a lightweight material for sitting. The final material is still up for grabs, but for the mock-up, the team used leftover oak from the woodshop. After nailing down the building process of the retaining wall and bench, the students made sure they had each block and its future location documented. Unfortunately, to complete the design the students needed five more 4′ 3″ X 10″ x 10″ concrete blocks. Good thing they’re pros at a concrete pour!

Prep it up!

To prepare for building the retaining wall, the students dug trenches for small footings. These concrete footings will prevent the wall from settling and becoming unstable.

After pouring the footings, it was time to create formworks for the needed concrete blocks. These were constructed from extra lumber, ZIP sheathing, and rebar. The rebar, leftover from the Test Building foundations, was crafted into cages and hung from the formworks.

With all this prep going on, the research team was also fine tuning their strategy for evaluating airflow in the Test Box small-scale experiments. They are currently working on revising an article for publication which details the results of these experiments and the potential for internal thermal mass design. In particular, Cory, along with Jeff and collaborator Remy Fortin, have spent months nailing down the proper equations for the airflow taking into consideration friction. Thanks to Russian physicist, Idelchik, he finally found an equation which matches the parameters of the TMBV experiments.

Meanwhile, Rowe and Livia revisited metal working, welding angles for the steel bench supports, and cutting metal mesh.

Put it up!

At long last, the retaining commenced! Something different about the actual wall and the mock-up wall is the addition of gravel backfill and landscape fabric. The landscape fabric and gravel cover the column bracings and drain, which runs behind the wall, to prevent corrosion and blockage from the hardy Hale County clay. However, the metal mesh than has to pierce through the landscape fabric so it can be buried in the earth behind. Hot take: expanded metal mesh and landscape fabric is the worse material combination ever.

To let out some steam on a very steamy day, they brought out the concrete saw and sledge hammers. The team needed to shorten just one 8′ x 8″ x 8″ by about 2′. Cory and Jeff showed the mailability of reclaimed cementitious materials.

Three courses up and the TMBV team could not be happier with the result! The pattern and the finger joinery at the shifting walls is just what they wanted. Best of all, she’s quite sturdy. The team will keep you updated on the progress of the wall so, as always, stay tuned!

Tags: concrete, groundwork, recycled materials, research project, retaining wall, Thermal Mass and Buoyancy Ventilation

Getting Down to the Details

November 9, 2020

Live from behind a stack of full-scale detail drawings, it’s the Thermal Mass and Buoyancy Ventilation Research Project Team! Lately, the team has been investigating all details inside and out. Starting out with material pallet and ending up at chimney flashing, the team is kicking it into high gear.

Cladding Material

1/4"=1' model of pods showing scale figure in cooling patio underneath — Iteration 1 Model

iteration 2 1/4"=1' model birds eye view — Iteration 1 Model

Unsurprisingly for a project so focused on the interior systems, it was difficult to make decisions regarding cladding. Initially, as seen in previous models shown above, the team experimented with separate cladding systems for the chimneys, Cooling Porch ceiling, and exterior walls. For iteration 1 of the test building design included a timber open-joint cladding system wrapping every surface. Next, for iteration 2, the cladding system wrapped only on the exterior wall faces of the buildings and the adjoining chimney faces. However, thin sheet metal covered the roof, cooling porch ceiling, and the chimney faces which touch those surfaces.

timber cladding + stacked timber walls and benches

The consistent cladding of iteration 1 appealed better to the monolithic nature of the SIPs structure. It also reinforced the importance of the chimneys to the buildings as a whole from the exterior. From there the team began to test if the timber was the correct mono-material for the test buildings. Seen above are renderings testing different materials for the cladding, columns, retaining walls, and benches. It is important to view these materials as they interact in the Cooling Porch. While sheet metal and polycarbonate cladding options may look more monolithic, timber is a low carbon material that better represents the heart of the project. In some cases, timber as a building material acts as a carbon-sink meaning it stores and processes more carbon than it produces. This of course relates strongly to the passive goals of the Thermal Mass and Buoyancy Ventilation Research.

Recycled Retaining Wall

Now the team is settled on the timber cladding, but they are not convinced of the retaining wall and bench materials. These aspects want to be a more earthen material as they rise from the ground towards the test buildings. After investigating rammed earth and concrete, the team wanted to find something more stackable. Concrete and rammed earth are beautiful, but they require formwork which requires more time. Something stackable will give the team more flexibility as well as members are movable.

Thankfully, down here on Highway 61 road work is being done to remove a load of 8″ x 8″ x 8′ stackable concrete barriers. The TMBVRP team is getting their hands on some of these reusable members and are calling around to local highway departments to find more similar materials. If they find enough, they will have a durable, stackable, and reusable material for their Cooling Porch. They can also use the old sidewalk pieces as a mosaic, ground material for the Cooling Porch. Above are drawings showing the use of these recycled materials.

Structure and Detailing

laptop screen showing Joe Farrugia on video call with students — living lengend Joe Farrugia on Zoom

For the past three weeks, the team has been meeting consistently with Structural engineer Joe Farrugia. He is guiding the team through lots of math to size their columns. While the gravity load on the columns is extremely manageable, the wind load is more difficult. The test buildings height means they will face more wind load than a structure this size typically experiences. However, Joe is confident that the structural system the team has chosen is doable with the correct column sizing.

While the team is attempting to draw every detail of the test buildings, they’ve found the trickiest spots to be around the chimneys. Making sure water moves off the roof consistently and air moves behind the ventilated screen is crucial. The TMBVRP will spare you the pain of walking through each flashing bend and board cut. Struggles emerge when the chimneys converge with the angled roof, but it’s very doable with lots of thinking, drawing, and redrawing. Then Andrew Freear and Steve Long, come in to save the day because how you’ve redrawn it five times is still wrong. Lots of covered wall reviews later and the TMBVRP team is on their way to compiling all the details in a digital model and drawing set.

students and professors gather in front of a wall full of detail drawings

Looking forward to keeping this momentum going, the TMBVRP can be found in Red Barn from dawn to dusk. Feel free to bring by some late-night snacks but for now thanks for TUNING in!