mass timber construction

Rain, Rain, Go Away

February 27, 2020

The Breathing Wall Mass Timber Research Project team has been quickly jumping between testing scales as the research continues. The test cell, introduced in the last blog post, is now finished- fully covered in a rigid layer of Geofoam insulation and ready for testing! The team is currently working on a large scale thermally active surface design to get these tests running.

Thermally Active Surface (TAS) construction

In the meantime, the team also built 1 of 2 test buildings. As a reminder, there will be two test buildings. One will be only mass timber construction and the other will couple mass timber construction with the Breathing Wall system. The team took advantage of every ounce of sunshine last week to build the mass timber test building in just under 3 days. Because of all the wood prep done before Christmas break and the threaded rod construction, all the team had to do was stack the 2x4s and 2x6s to form the walls.

mass timber testing building in progress

The ceiling was the real trick. Because the threaded rods for the walls run through the floor and the ceiling (tying the whole test building together), the team had to ensure the holes on the ceiling would line up perfectly with the vertical threaded rods. So the team built the ceiling off site, tightened it down to an exact measurement, drilled the holes, then took it apart. When the walls were up, the ceiling was installed in exactly the same order as it was assembled before to ensure the holes lines up with the threaded rods. Next up, doors!

Stay tuned for another test building, doors, and a roof coming together very swiftly.

Praying for sunshine,

The Always Damp Breathers

Soundtrack: Have You Ever Seen the Rain? | Creedence Clearwater Revival

The Return of Zelda

February 4, 2020

As construction continues, the team is also spending their spare time (ha!) scaling up in the horizontal and vertical sock tests. Each increase in scale comprises of another variable added to the test. This testing method isolates the effects of each variable. The horizontal sock test has moved up in scale to a new test box the team lovingly refers to as Zelda – you may recognize her from earlier air infiltration tests, where the team was experimenting with different laminated timber assemblies. Zelda adds the element of these laminated panels in a forced-air system in comparison to the previous solid wood panel. With the laminated panels, the team will also be testing different hole spacings for the Breathing Wall to try and find the most optimized geometry for the Test Buildings.

Jumping even larger in scale, the team is constructing their test cell. This cell serves as a way to test a full-scale Breathing Wall in isolation. The cell is the same dimension as the future Breathing Wall Mass Timber test buildings, but the floor, ceiling, and three of the walls are standard stud-framing with hyper-insulation. The Breathing Wall is added to one side of the cell for testing. This eliminates the variable of the mass timber construction so the team can use this data to compare with their final test buildings. One of those buildings will test the whole Breathing Wall Mass Timber system, while the other will be only mass timber to serve as a control. Like the rest of their experiments, these steps should allow the team to understand the impact of each variable and strengthen their understanding of the whole system!

Stay tuned for a fully insulated vertical sock and test buildings!

Always adding to our material palette,

The Itchy Insulators

Soundtrack: The Scientist | Coldplay

Tags: breathing wall, mass timber, mass timber construction, natural ventilation, research project

Continuing to Poke Holes in Things

February 1, 2020

The research team has spent the past few weeks constantly shifting between testing and building which keeps things exciting around here. With the floors for the two test buildings in place, the team spent about three weeks preparing each piece of wood for the walls and ceiling. Over 700 pieces of wood were cut, labeled, drilled (4000+ holes), and stacked. For a while, the team operated each day under the fabrication pavilion like a well-oiled machine. Each team member had their job: book-matching boards, clamping templates, drilling holes, stacking finished pairs. By the end of those weeks, the team could prep an entire wall (~80 boards, 400 holes) in a little over a day!

Stay tuned for mass timber walls!

Cleaning saw dust out of our ears,

The Rural Studio lumberjacks

Soundtrack: Chop Suey | System of a Down

Tags: breathing wall, mass timber, mass timber construction, natural ventilation

And Suddenly, Floors!

November 22, 2019

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

Tags: breathing wall, mass timber, mass timber construction, research project

Steel Fabrication

November 21, 2019

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!