formwork

Square Up for Concrete

After weeks of weather-watching, schedule-shifting, and dirt-digging, the day arrived. Slab day! Let’s cut to the chase, she’s a beaut. Would you just look at that big hunk o’ concrete!

Myers’ Home Team after a long pour day

But how’d Myers’ Home team get here? That clean, final slab contains quite a few parts. The layers within the slab are gravel, a vapor barrier, rebar, and wire mesh. These all had to be installed along with plumbing and electrical chases before calling in the concrete order. Not to mention the formwork that holds the whole thing together while it cures!

Peak Form

The batter boards that went up all those weeks ago set the lines for formwork. The form boards are tacked with metal stakes every two feet, leveled, plumbed, and secured with kickers and wooden stakes every four feet. This solid edge allows the team to dig their 8″ wide turndowns with crisp and clear dimensions. The turndown is a small ditch that strengthens the edges of the slab which are taking the brunt of the gravity load of the home.

Riley loading up the wheelbarrow for another round of gravel

The site was a touch too muddy to bring in the big guns (the Bobcat) for gravel moving. So gravel moving was done the good old-fashioned way with wheelbarrows and shovels. Cheers to the Studio’s new Operations Manager, John Allen, for joining the student team on quite the pre-summer scorcher! The old gang and their welcome extra hands then spread the gravel with shovels and rakes, tamped flat and firm, and checked for level with the site level.

A site-sized sheet of thick plastic, the vapor barrier, covers the gravel and sprayed for termite protection. With all this tamped down and taped up it’s time to get into the metal game!

Rebar is skewered throughout the turndown and run lengthwise around the edges. Metal mesh is then carefully moved, it tends to be wiggly, and cut to size to set on chairs across the slab area. These elements reinforce the slab for tensile strength after the pour.

Water Under the Drive

Meanwhile, the team was also trenching for water lines for, long-term, the home’s water supply and, more short term, a spigot to water their new concrete. The Ditch Witch, a walk-behind trencher, is a gem of a machine. Once you get her started, she can dig a line like no other! After completing most of the trench and chiseling through a few unexpected brick foundations by hand, the team finished a long Slab Pour Eve with a complete and working hose.

The Promised Pour

But at last the morn arrived! The first concrete truck pulled up right on time (wow!). With expertise of local concrete masters Clyde and Jimmy, the team had their slab placed in a jiff. The team was able to help float edges and directing the placement of the small excess load. As Clyde continued to finish and polish the surface, the team prepared to pop their markers for control joints. These prevent large-scale cracking in the slab over time.

Clyde returned the following morning to cut control joints with the demolition saw. The team took turns to water the slab morning, noon, and night in the days following.

This means these three students are just about ready to start framing! Stick around to see the mockup they’ve got in the works for all those durable details and some sweet and sweaty Pig Roast moments!

Week 77: A General Update

Students working outside on Morrisette Campus

Live from Newbern, Alabama, it’s the Thermal Mass and Buoyancy Ventilation Research Project Team! 77 weeks in Hale County and the graduate student team is still firing on all cylinders. This post, they’ve got updates on concrete panels, drainage, and the steel walkway and stair. Plus, the wonders of the Wood-Mizer, a portable sawmill, for those readers who make it to the very end!

Panel Pour Product

Section Isometric: a peak at the interior concrete panels

A couple of weeks back the TMBV team poured four, new concrete panels. These panels were designed to test tongue and groove joining system. Also, this round of test concrete panels experimented with vertical formwork.

As predicted during the struggle of formwork construction and concrete pouring, the vertically poured panels did not turn out so well. However, the team made promising headway with the new joining method. Alright, now that the panels have cured, let’s take a look at the material.

First, you’ve got to remove the panels from the formwork. You know from the team’s previous post that one of the vertically poured panels did not make it all the way through pouring. Look at that; live edge concrete!

However, the smaller vertically poured panel survived! The results were surprising, as seen above this panel had more air gaps than the traditionally poured panel. The students previously thought having formwork on all sides would create more even and consistent panels. But, without an open surface to trowel, the vertically poured panels were subject to more air bubbles.

The typical, horizontally poured panels turned out smooth and even as ever. And just look at that grooved edge!

Diagram showing the corresponding concrete panel surfaces and joints

Next, the concrete panels were attached to the Fabrication Pavilion pin-up wall to test the joints. The results were inconclusive. Some tongue and groove joints turned out well, while others broke at the edges of the panel. Going forward, the team wants to attempt a shiplap joint for the panels. Also, they’d like to make more, smaller test panels to assemble in a miniature wall configuration.

Drainage Days

As you can imagine, in the everchanging weather of late, the Test Building site became the town swimming pool. The 18″ deep hole containing the foundations was nearly filled to the brim during the past weeks’ rain. Luckily, the team, Mason, and a mini excavator got out while the sun was shining to install the drainage. The French drain leads from the Cooling Porch, betwixt the foundations, into the forest line.

Rain between two foundations leading to woods

Walk this way

You might have been wondering how one day you might access the 30′ tall, 8′ above ground Test Buildings. Well, you’ll use the steel ships ladder and walkway of course.

Enscape rendering of Test buildings

As of late, the TMBV team students have been designing the fabrication and installation process of the stair and walkway. To detail the stair fabrication process, they partook in a classic rural studio technique; the cartoon storyboard.

cartoon showing assembly of steel stair

Next, the team planned out the order of installation of the walkway and the SIPs structural floors. First, they plan to place and secure one assembled SIPs Test Building floor. Second, place the other Test Building floor, using the walkway steel angle frame to square the two to one another. When everything is properly adjusted, lag screw the steel angle frame to the SIPs floors. Third, place 1″ metal grate on top. Next, place and bolt the stair to the walkway and ground connection. Lastly, site weld the handrails to the exterior face of the steel angle frame. Voila! It’s that easy if you only have a crane!

Wood-Mizer Wonder

And the special bonus; a portable sawmill! Adam Maggard, an Auburn University Forestry and Wildlife professor and Extension Specialist in Forest Systems Management, travels the southeast with the Wood Mizer portable sawmill conducting forestry management research and reaching out to family, forest land owners. Adam collaborates with Auburn Architecture Professor and TMBV colleague David Kennedy and Rural Studio Alum Will McGarity. The three gave the students a Wood-Mizer tutorial as well as an introduction to their research.

Rev. Walker’s Home Project team requested the visitors to help mill some gorgeous tree’s from Rev. Walker’s land. Each student took a turn milling down either the cedar or pecan tree. The students were amazed by the machine and even more amazed that freshly cut cedar is bright, pink. It was a remarkable experience, big thanks to Adam, David, and Rev. Walker from the Thermal Mass and Buoyancy Ventilation Research Project Team!