insulation

Starting the Summer at the 18×18 House

The 18×18 House team has been BUSY! The end of the spring semester came fast, bringing a big ol’ Pig Roast celebration with it. Dozens of family members, friends, and alumni crowded around the house to see what this project is all about. We had a great time sharing the work, and figured out just how many guests can fit onto two parking spaces…

Post-Roast Tasks: Roofing

After the fun of Pig Roast, the “18s” hit the ground (or the scaffolding?) running to get the roof installed. Without a watertight roof, the team couldn’t install insulation or drywall, so it was the priority. The first step was laying rigid insulation over the roof sheathing, then attaching purlins across the top. These purlins will be what the metal panels are screwed into later.

Then all the corners and edges got metal flashing installed on them. The whole roof was outlined in metal profiles to keep water OUT!

The team laid the metal roof panels across the length of the house, attaching them one by one. The back side of the roof was the easy part, but then it was time for the dormer…

Before installing the metal on the front, the team had to install the roof and the siding panels on the dormer. If they didn’t, there wouldn’t be a way to reach the dormer walls later. Meagan and Jake did some tricky flashing work from the scaffolding to install everything over the purlins and insulation. And then, a finished dormer emerged!

The rest of the panels went on smoothly after that. And isn’t it pretty? After it was finally done, Meagan took a break.

Insulation Nation

But no time to stop! As soon as the roof was finished, it was time to insulate. The 18s stuffed the house full of hemp wool and mineral wool batts. And then some more mineral wool. And then some more… Let’s just say there was plenty to do. Meagan had to take another break.

Closing in the Walls

The last step before drywall can be installed was to hang cement board in the bathroom. Cement board is a water-resistant substitute for drywall in showers and other wet areas of a house. The team will be tiling the walls of the shower later on, and this will provide a sturdy base for it. Julie and Meagan measured each panel, scored them with a utility knife, and broke them along the scored edges. Then Meagan took a break, again.

And drywall was delivered to the house this month! We watched as the sheets were lifted into the house through upstairs windows. It all fit inside just fine, and the house is once again crowded with materials. All that’s left now is to hang it up!

We aren’t the only ones eager to see what will come next at the 18×18 House. Watch out to see what happens as summer goes on!

Kitten in doorway
Awwwwww

Insulation and Other Sensations

Oh hi, didn’t see you there behind my giant block of Geofoam insulation! Let me explain. Recently, Thermal Mass and Buoyancy Ventilation Research Project Team has been designing their first experiment, the desktop scale experiment known as “the chimney,” and building a mock-up of it.

The team used the data obtained from the thermal conductivity testing in Auburn University’s material testing lab along with their test concrete panel making experience to choose which concrete mix to use. They are going with Quikcrete Pro-Finish 5000, a high strength, smooth finish mix. Next, the team poured nine new concrete panels at the adjusted thickness. The thickness of the panels increased slightly due to inputting the exact thermal properties of the concrete mix into the code of the optimal tuning application.

The desktop experiment takes the form of a 3″ x 1″ x 1″ chimney with the thermal mass panels facing the interior. The desktop experiment needs to operate in nearly ideal conditions which means eliminating as many variables as possible. It is important to remember this is a scientific experiment of an unproven theory of how an internal thermal mass can be sized for a space to control temperature and promote proper ventilation. Therefore, to eliminate the variable of heat loss or gain from the exterior to the interior, and to understand how the thermal mass panels themselves are working, the chimney needs to be highly insulated.

When you need R50 insulation, even for such a small structure, it can get expensive and big. Their creative solution to getting the proper insulative value without spending hundreds of dollars per test was combining Geofoam and Rockwool! EPS Geofoam is much like rigid insulation but is typically used for earthwork such as building up underneath highway on-ramps. It is very dense giving it more insulative value per inch. Rockwool is a rock-based mineral fiber insulation. Thankfully, Rural Studio had extra R30 from a previous donation. The Geofoam was also donated, the Breathing Wall Mass Timber team got in touch with a construction operation that had extra and transported it to Newbern. In the drawing above you can see the concrete panels screwed onto a piece of 1/2″ OSB and 2″ Geofoam which is then surrounded by 9″ of Rockwool then encased by another layer of 2″ Geofoam. This combination of materials results in R50 insulative value.

The Geofoam comes in giant 8″ x 4″ x 3″ blocks because they are typically stacked underground. So another creative solution was needed, how to cut it down to the size we need. The TMBV team did not have to think too hard on that one because their big sister research team, the Breathing Wall Mass Timber squad, had already built a hot wire cutting system for their own Geofoam needs. A copper wire was spanned at the desired height above a table and heated using cables and an external power source.

Next, the Geofoam block was slid across the table and cut through by the hot wire. Once the Geofoam is at a more manageable size it can be cut using a hack saw. Shout out to the best big sister research team ever, Fergie, Jake, Preston, and Anna, the TMBV team appreciates you!

Whew, that was a lot of insulation talk! To ease everyone’s mind here is a beautiful Newbern sunset. See you next week!