A Sustainable, Self-Powered (and Real) Modern Farmhouse Built with ICFs
Two Chicagoans turned organic farmers made for the perfect clients for sustainable architecture firm Tom Bassett-Dilley Architects (TBDA). The couples’ custom—and literal—farmhouse needed to reflect their lifestyle: healthy and good for the earth.
“A lot of our clients have a sense of mission. They feel like, ‘Well, if I'm going to do something and build something and contribute to the world in this way, that should be something I can believe in. And I can feel good about leaving something behind that will have lasting value,’” says Bassett-Dilley. “That was all motivation for [clients] Paul and Marisa.”
The home needed to be high-performance and produce energy for not just the family of four but their entire cattle farm, Starry Nights Farm. It achieves this net zero goal through insulated concrete forms (ICF) construction, focusing on air tightness and healthy interiors, passive house principles, heat pumps, solar panels, and, when those Wisconsin winters hit and tested those heat pumps, a pellet stove. And its efficiency is wrapped up in a modern farmhouse design with a quaint, thoughtful interior.
Healthy Specifications
The original plan for the home was a deep energy retrofit and remodel of the existing farmhouse, but with a crumbling foundation, deteriorating surfaces, and structural awkwardness from old additions, an entirely new home in its place became more realistic.
The new build needed to retain a charming farmhouse aesthetic that would look natural on the sweeping 140 acres of farmland. Clients were comfortable with a traditional form and color, so the architect selected LP SmartSide board and batten and horizontal siding. The siding’s prefinished, engineered wood construction helps keep embodied energy low, and its long warranty and durability would increase the product’s lifespan.
Bassett-Dilley worked closely with the clients to develop an interior full of minimalist warmth and their unique character that still balanced with the natural setting.
“The idea was that it was the house is pretty much a backdrop to this incredible landscape,” says Bassett-Dilley.
The clients also required an extra bedroom, living room, and kitchen for their agritourism in the basement, where visitors who book on Airbnb stay.
Shiplap, rustic woods, and textured tiles helped infuse a farmhouse style into the interiors, and all specifications were made to ensure indoor health. TBDA selects building products based on Greenguard certification or the International Living Future Institute’s Declare label, down to the caulks and sealants used, like AFM Safecoat products.
For paint, the firm specifies non-toxic, not just low VOC, such as ECOS or Milk Paint.
Cabinetry remains tricky because many pre-made cabinets contain some formaldehyde, says Bassett-Dilley. To mitigate this, the architect selects custom cabinetry with formaldehyde-free plywood, such as PureBond from Columbia Forest Products.
Building with Insulated Concrete Forms (ICF)
The client requested the home be built with materials stronger than wood, so the team selected ICFs. TBDA previously built two homes with ICFs and chose to work with Tim Pinter of Acts Construction, who uses Crown ICF, in Kenosha, Wisc., collaborating early to tackle issues early on.
A key importance of ICF homes is ensuring air tightness, says Bassett-Dilley. Bringing Pinter on early helped to create a plan of attack for leaky areas such as window openings, wall-to-roof connections, wall-to-foundation connections, and course heights for the ICFs.
Bassett-Dilley and Pinter worked closely on visualizing and preparing for the intermediate floor connection where the floor is suspended from the walls due to the thermal bridge potential. The solution is understanding the methods of each ICF system used to support a floor truss, as each one differs.
Window opening bucks also vary by ICF manufacturer. Some use plywood, double plywood, or wood, and Bassett-Dilley says this is a “really important detail,” to iron out ahead of time to understand how to fasten windows to the ICF.
Planning air barriers for the roof trusses is another vital detail to prepare ahead of time. In this home, the team used plywood as the air barrier between the trusses and ICFs, then an inch and a half of service cavity under for electrical. Then, that barrier needed to be sealed off.
Another critical player in the air tightness was the Phius (Passive House Institute US) energy rater, Juanita Ellias of Rivercity Woodworking. A collaborative rater can provide valuable solutions, as she did on this project with the contractors.
“Juanita became a real advocate for the client and helped bring the contractors in line or to help troubleshoot any issues they had,” says Bassett-Dilley. “When you're on the construction site, thinking, ‘How am I going to get this to go here to there? How am I going to seal that?’ That's where the third-party rater can really help out.”
Using Pellet Stoves as Energy Backup
The architect selected an air source heat pump and heat pump water heater. The water heater also provides radiant heat to the basement slab, where the guest suite is.
But while extremely efficient, heat pumps can be challenged by the intense Wisconsin cold. Though they work, their efficiency drops. With this being an extremely tight passive house, the chances of any freezing are extremely low.
But as a safeguard, TBDA installed a couple of pellet stoves that use little of a home’s battery backup to ignite and are thermostatically controllable.
“They’re a nice backup heat source,” says Bassett-Dilley. “They also provide radiant heat, which is a nice quality of heat when you can feel the heat coming off of something. So, we put one in the middle of the first floor, and it's a nice feature on several levels: resilience, comfort, and peace of mind.”
The stoves burn pellets made from recycled sawdust that’s low carbon and inexpensive.
Solar Array and Power
To seal the net zero plan, TBDA placed a large solar array on the home’s southern-facing standing seam metal roof.
Though powering the home and farm may sound like a large energy need, the clients’ organic regenerative approach to farming requires much less power, and they outsource refrigeration.
Architect: Tom Bassett-Dilley Architects
Structural Engineer: Olympic Engineering
Builder: Tim Pinter, Acts Construction, Crown ICF