A quadruple pane window from Serious installed in a hempcrete wall in the Nauhaus Prototype

Well, we finally got the windows and doors installed. Okay, let me vent for a sec: prototypes are a bitch. We had to do a lot of head scratching and trial and error to figure out the best way to insure airtightness in our installation. The hempcrete is awesome, but it create its own set of challenges, especially since our truly wonderful Serious windows aren’t really designed to be installed in the middle of thick walls. (Serious is a partner with us on this project and we’re working with them to make things easier when you decide to replicate what we’re doing.)

First, let’s sing the praises of these windows. Though a number of German companies make windows in this category, Serious Materials is the only US company that can meet the required specs for a Passive House. All window and door units on the project have fiberglass frames and quadruple pane glazing. Southern glazing has a center of glass insulation value of R-7 with an impressive solar heat gain coefficient (the percentage of solar heat that passes through the glass, 1.0 would be 100%) of about 0.7. This allows for heat gain from the low southern winter sun, a strategy integral to the Passive House integrated design system.

North, east, and west glazings weigh in at an amazing center of glass rating of R-11, a rating equal to the fiberglass insulation in some conventional stick frame walls! This is compared to R-2 for a typical double pane window found on most US projects. Unlike the heavier European windows, Serious reaches this performance level with two pieces of glass and two pieces of plastic allowing for a thinner profile more like conventional windows typically available in the US.

Why all the fuss? Well, I’ll tell you. In a Passive House in our climate region, walls need to be about R-40.  Sticking an R-2 hole in an R-40 wall just doesn’t make sense.  In a Passive House, the idea is to spend money on passive elements, extra insulation and really good windows for example, that don’t require energy inputs to do their job once installed, unlike heating, cooling, and ventilation equipment. In the right configuration, these passive elements combine to allow for a much simpler and less expensive mechanical system, thus saving money in construction and afterwards with much lower energy bills.

Anyway, we’ve got video footage that we’ll eventually compile into a bunch of great educational how-to videos on the ins and outs of all this nifty construction detailing. If anyone out there is getting antsy for the goods, getting us a grant to fund collation of the documentation footage would really speed things up. Until then, wet your chops on these few photos:

Here you see our custom plastic lumber sill piece with groove for backer rod and space for spray foam, the edge of the bituthane sill pan (green stuff), and the poured in place concrete exterior sill.

All windows had to be pre-drilled through the fiberglass frames...

...then screwed to the stud framing in the middle of the hempcrete wall.

Jeff puts his engineering degree to work installing a backer rod as part of a multi-step installation process to insure maximum airtightness

The plastic lumber sills were filled with foam after installation through a series of pre-drilled holes...ingenious!

Southwest view showing windows installed. Doesn't look like any big deal, does it?

Master carpenter and benevolent genius Tim working on a door. Installing the doors was a whole different story...don't get me started!

If you think the US is a capitalist country, think again. We can buy all the industrial hemp products we want, but we can’t grow the raw material to make the products ourselves. Can you say, “trade imbalance”? To learn a bit more, watch these two short videos we were involved in that discuss industrial hemp generally and then specifically as it applies to our Nauhaus prototype:

If you’re interested in volunteering for the Nauhaus Prototype Project, please contact Billy.

Click here to view the entire Nauhaus Prototype Construction Chronology.

Current View of Southeast

Current View of Southwest

Hemp Stacked and Waiting

The Trusty Mixer

Adam is the fastest Hemcrete installer in the West!

Support for Upper Forms over CMU Wall

Closeup of Form Attachment

Scaffolding

The forms are built up almost ot the overhangs, and are stuffed by hand.

Completed Window Opening

Thermally broken mounting bracket for roof supports. The pink is foam insulation.

Closeup of Hemcrete in Form

A combination of custom and pre-made forms is used on the 2nd floor.

If you’re interested in volunteering for the Nauhaus Prototype Project, please contact Billy.

Click here to view the entire Nauhaus Prototype Construction Chronology.

Wall with Custom Hemcrete Forms

Wall after Hemcrete Forms are Removed

Serious Materials Windows Have Arrived

Serious Materials Windows Waiting for Installation

Head and Jamb of Hemcrete Window Opening

Jamb and Sill of Hemcrete Window Opening

Sustainably Harvested Hemlock Fascia

Closeup of Future Patio Connection at West Wall

Nauhaus Prototype as of December 31, 2009

If you’re interested in volunteering for the Nauhaus Prototype Project, please contact Billy.

Click here to view the entire Nauhaus Prototype Construction Chronology.

Ian Snider and Jeff Buscher

House with forms on the South side.

Elisha measures.

Shutter being attached.

Elisha

Sarah tamps the Hemcrete.

Hemcrete in Mixer

Nauhaus Building Systems mixes Hemcrete.

Shutters line the interior South wall.

Interior of West and North walls without forms.

Electrical Box in Hemcrete

Click here to view the entire Nauhaus Prototype Construction Chronology.

Buckets of Hemp

Custom forms on Completed Framing

Exterior Bracing at Plywood Forms

Custom window forms were built so that the jambs could flare out and let in more light.

Horizontal form supports are painted orange, as they will be removed after the the Hemcrete is packed in.

Matt pours hemp into the mixer.

Nauhaus Team and Volunteers Installing Hemcrete

A volunteer tamps down Hemcrete around the studs to ensure a tight seal.

Sarah tamps Hemcrete. At this point, the forms are 4' high because the first 2' layer is completed.

Today, as the Hemcrete installation continued, Amy Musser of Vandemusser Design came out to give us a LEED consultation.  The Prototype is still on track to receive LEED Platinum certification.

Amy Musser, Luly Gonzalez and Chris Cashman discuss LEED.

Northwest Corner of Nauhaus Prototype

………………………..

Well, one wall anyway.

Yesterday Ian and Mario from Lime Technologies came out in the rain to help us install some Hemcrete, starting the first home in the United States to be built with the product.

The rest will be installed after the Eco Panels go up.

Click here to view the entire Nauhaus Prototype Construction Chronology.

Click here to watch the full interview with Ian Pritchett.

We were excited to have Ian Pritchett and Mario Machnicki from Lime Technology, makers of Hemcrete, come by to check out our building for the first time.  We had some great discussions about Hemcrete, earthen blocks, construction details and more.  The electrical work has been completed, and the walls are ready for the hemp installation.

Jeff Buscher, Tim Callahan, Ian Pritchett, Mario Machnicki

Ian Pritchett and Jeff Buscher talk about earthen blocks.

Southeast view of the nearly-completed framing of the Nauhaus Prototype

Electrical Box Installation

The electrical boxes are mounted on blocking so that they will be flush to the inside of the 12" walls.

Click here to view the entire Nauhaus Prototype Construction Chronology.

Scored Concrete Slab

Scored Concrete Slab

Hemcrete Mix

12" Hemcrete Form

Completed Hemcrete Wall

And here’s papercrete being pumped.