A Tiny House Plan Proving Big Ideas
Project Spotlight: Terran Palmer-Angell
Our customers are typically interested in building better - with more concern for the environment, energy use, natural materials, and people’s health. Occasionally we have a customer with very particular and serious needs and Terran Palmer-Angell has been one such customer. Terran not only had ambitions that aligned with our own, but the care and execution he and his contractors have shown, has been exemplary. Terran went above and beyond to research his decisions and document every step of his process while building his Tiny House On Wheels (aka "THOW" within the Tiny House community parlance). We hope to package more of his experience into bite-size articles for the 475 blog, but in the meantime, we are proud to bring some highlights of his story to you:
About three years ago, some friends, family and I set out to build a tiny house to help with chronic health problems I’ve had since childhood. The structure would need to be free of chilling drafts during colder weather (it gets down to around -30 F here on some winter nights) free of building materials that caused Toxicant Induced Loss of Tolerance (TILT) style allergic reactions, have a good (and properly sized) supply of fresh air in the form of Heat Recovery Ventilation - and would need to be as efficient as possible to fit with my budget for the foreseeable future, and also with all of our values. Early on, we struggled to find materials that would fill these needs. We thought it seemed likely that we would have to wind up building, more or less, another version of the kinds of structures that have made life challenging for me in the past. But then a retired contractor mentioned Passive Haus to me, and said if he were doing the project, he’d try his best to see if he could build it as close to Passive as possible. I started looking into companies that offered Passive Haus products, and the first two places I spoke with mentioned 475 immediately, as the best resource I could connect with. I am extremely grateful that they pointed me in that direction. For several months, I’ve been living in the final product of what we built, and it has changed my life. It is by far the most beneficial structure for my health that I’ve ever lived in. Truly efficient Tiny Houses are far too rare, and comfort can become a huge issue in tiny spaces that are not well insulated and/or drafty. There’s nowhere to escape drafts and excessive heat or cold sources in a tiny house. They’re also awfully small spaces to share with moldy surfaces and cavities of walls, roofs, and floors that have moisture issues over time. I have heard horror stories of how much these factors can impact tiny house occupants.
Passive House for Tiny House?
Long-story short: here in Upstate NY, just south of the Canadian Border (the closest Climate Data Set was either Ottawa or Montreal) there’s just no way to fit enough insulation into a road-and-residence-legal building envelope to make it certifiably Passive...After working with the PHPP for many hours, I was able to get a sense of how much energy I’d be using for the plan I settled on: I’d be consuming about the same amount of energy as a relatively modestly-sized, certified Passive Haus (PH). To me, that realization contextualized my situation: rather than build a Certified Passive Haus on a permanent foundation, I was choosing to build a small, mobile structure that specifically suited my needs, would cost significantly less, and used the same amount of energy.
Under these circumstances, foam can be tempting: It’s light. It appears to have the maximum R-value per inch of all available insulations save for Vacuum Insulated Panels (VIPs.) It can also come in differing forms (spray, board, roll, exterior roofing spray, etc.) However, even the most trustworthy professionals in the foam industry I spoke with emphasized that [closed cell] spray foam will lose significant R-value over the course of its life. It will be dimensionally unstable, eliminating it’s proposed air-sealing value, and potentially creating gaps in wall-cavities over-time. It is expensive....and spray-foam can lead to disaster if minor aspects of the install go astray.
Air Sealing, Ventilation, and Heating:
Because we wanted to avoid drafts, foster dry wall cavities, avoid the formation of mold throughout, and have good control over the interior air-quality of our Tiny House, air-sealing and ventilation were incredibly important to us. We were extremely happy to find that 475 had products that worked perfectly for these purposes, and had extremely rigorous testing and research backing them.
There are so many good intentions in the tiny house community, and I worry that far too many people wind up with spaces that fall short of what they expected in terms of comfort, health, and efficiency. I’ve been inspired by folks who broke out of the mainstream to experiment with addressing those problems – like Robert and Samantha at Shedsistence, and the Leifhouse in Canada. I hope we can all work together to make tiny structures live up to their potential, and become functional, comfortable, efficient, affordable, and legal spaces for people to live.
We couldn't have said it better ourselves. Thank you, Terran!
Materials & Components Rundown:
What exactly did Terran implement from 475? Here's the list: Pro Clima INTELLO PLUS inboard airtightness and smart vapor retarder (with service cavity), taped with TESCON VANA. Outboard SOLITEX MENTO 1000 monolithic WRB with TESCON VANA tape. Windowsill pans with EXTOSEAL ENCORS and frames taped with split back TESCON PROFIL. Undercarriage airsealing and capillary break with EXTOSEAL FINOC. Roof underlayment of SOLITEX UM with integrated 3D mesh and TESCON VANA tape. Ventilation with e2 and eGO through-wall decentralized high-efficiency heat recovery units by Lunos.