Digging In

Vol 1., No 5

The build team will be on site as of early July–we’re excited for them to begin! We’re doing three projects to give them a running start when they arrive:

Stripping the house’s exterior: We removed the aluminum siding (which is on its way to be recycled), and are removing the clapboards that were underneath the aluminum siding. Given their condition, the clapboards will unfortunately be on their way to the landfill.  This will allow the team to start right away on any repairs necessary on the exposed sheathing and sill beam before they start putting a “jacket” (thick, insulated walls) and “hat” (higher, insulated roof) on the part of the structure that was the original footprint of the house Moses Chaplin and his friend Aaron Campbell built back in 1782. 

Clapboards coming off the original structure, with the 1 inch board sheathing exposed

Pushing dirt around: We (in this case, the “we” is Jason Dow, a neighbor and the person in charge of the excavation work on the project, amongst other things) dug some test pits to assess soil suitability for a horizontal loop ground sourced heat pump system for heating/cooling and hot water, which is our currently favored plan. Jason also did some trenching to determine whether the hillside on which we plan to install our ground mounted solar array can be reshaped to help us tuck the array into the hill and largely out of sight from the house. So far, so good on both fronts. The array will be installed by mid-July.

Test pits for the horizontal loop ground source heat pump assessment

Siting the solar array on a sunny day

Moving things inside, and taking inventory: The external footprint of the original house will remain essentially untouched in this project (except for fatter walls/roof). The extension off the back of the house, that was added in what was likely the 1830s, is going to be deconstructed.  I say “deconstructed” versus “demolished”, because we will reuse as many materials as possible in the new structure that will replace and extend this part of the house. So, we are taking an inventory of the barnboard, large beams, floorboards, doors, and hardware, so we can begin to design these elements into the new structure. 

The 1830s addition that will be deconstructed

High Level Goals

As we’re about to head into construction phase, it is worth a moment to outline some of the high level goals we set for this project, which will enable deeper dives on the choices we are making to support these goals. They are:

1. Create a beautiful home that pays tribute to its history, enables a contemporary lifestyle, and extends the life of the home for the next 240 years. We specified design elements to support the life we hope to live out in this house with our family and friends. It won’t surprise anyone who knows us that this revolves around entertaining and hosting family and friends. The team has done a great job working them into the design as it currently stands. Details on that as we go. 

   

   The design team gathered for a planning day…clearly we’re having fun! Also, the roof sags a bit, and that is funny I guess.

2. Net zero operational carbon. All the ongoing energy needs to operate the home will be met by renewable energy sources that don’t emit carbon pollution to generate that energy. For us, this is supported by a few key elements: (1) build an airtight, well-insulated structure, and focus on efficiency to reduce energy needs, (2) make all systems be powered by electricity: heating/cooling, domestic hot water, cooking, etc. and (3) install solar photovoltaics to produce the energy the house needs to run on an annual basis.

3. Minimize embodied carbon. This concept has gotten much less attention than “net zero operational carbon” until recently, despite being a major contributor to carbon pollution from the building sector. Simply put, “embodied carbon” reflects the CO2 emissions resulting from production of the materials used to construct the building. Materials choices can make a huge difference on the embodied carbon of a building. Chris Magwood has put together a 5 min video explaining this concept more fully. It is well worth watching. And if you want to see all the cool (pun intended) implications of making materials choices with embodied carbon in mind, from drastically reducing embodied carbon all the way to turning a building into one that sequesters carbon (!!), you can check out this slide deck. 

This emphasizes that in a high performance home, the embodied carbon matters much more than operational carbon emissions in the window that really matters (before 2050). A net zero home reduces that blue area to zero. Now we need to make the yellow area as small as possible!

Builders for Climate Action (BCA) recently released an embodied carbon calculator, called BEAM, that allows a fairly simple estimation of the impacts of materials choices on embodied carbon for a build. 

The work of the BCA and many others have identified the biggest drivers of embodied carbon in many buildings:

1. Concrete. Reducing its use, and using concrete with supplements to reduce the amount of Portland cement required, can help here.

2. Insulation. Some insulation types have high global warming potential (e.g.--spray and board foams), while others can sequester carbon (e.g.-- dense-packed cellulose)

3. Cladding. Brick has lots of embodied carbon, wood less so. 

We’ve kept all of these in mind during design, and I’ll be putting our current design through a BEAM assessment very soon, to understand where we are now and what other choices we might consider. 

Minimizing material use overall always helps with embodied carbon as well. Keeping the original structure, and reusing materials from the old addition, will all help in that regard. 

I look forward to sharing stories from the build site, and expanding on some of the above concepts with specifics from our project, as we move into the next phase!

A few closing thoughts 

I recently asked Jason about something I’d read while doing research on the history of the house–mention of a single family burial plot somewhere north of our property.  He told me that, indeed, there was a plot on a neighbor's land, and that he and the neighbors  (being the good folks they are) had marked the area so it would be respected and preserved. Jason said this plot marked a family who had all died of scarlet fever sometime in the 1800s.  I was struck by this, having just recently been laid low by a case of strep throat, which is caused by the same organism that can give rise to scarlet fever. My case was treated effectively and easily by a round of penicillin. A little reading revealed that lethal epidemics of scarlet fever were a common occurrence in the region in this time (e.g.--see here).  How far we’ve come to be able to identify and respond to infectious diseases since those times, thanks to modern science and medicine. We are by no means perfect in our public health responses, as our most recent pandemic has laid bare. But as a scientist who has spent decades in the area of making new medicines, I am grateful to live in this time, when we have the ability to deploy science to alleviate human suffering. I am encouraged to see this same human ingenuity being applied to the climate crisis. While addressing this challenge will not be easy, I remain confident we will ultimately succeed in effecting a clean energy transition. 

Oh, and for those who expressed interest in the provenance of the apple tree I mentioned in a prior post, the samples are at the lab and we should have genotyping  data in a month or so!  Also, I learned about the remnants of another old orchard on the property, which we may try and reinvigorate in the coming years.

Part of last year’s “mystery apple” harvest. Tart and yummy!