Real People + Real Problems + Real Solutions

There’s rich history in the mountains west of Boulder, Colorado, where gold was discovered in the 1800s and is still mined in towns such as Gold Hill today. Along with rags-to-riches and hard-luck tales, the boom era has left a legacy of abandoned mines and old mining shacks that are now being reclaimed and renovated.

Tracy Ferrell and her husband, Tim Zych, are two of the new pioneers who have a passion for sustainability—ironic given that their home comes from an era that was anything but green. The couple bought a 150-year-old mining cabin in Gold Hill and are now remodeling it to accommodate their family. Tracy’s question is: Can an old structure once associated with extractive mining practices now attain the energy-efficient, resource-conserving, healthful standards of green building?

Tracy and Tim want to make their cabin, which is a historical landmark, as green as possible, but they’ve found it difficult given local historical society constraints. Space is an issue, and they aren’t allowed to alter the outside of the building significantly (including adding rooms) because of historical renovation laws. Working within these constraints, the pair has chosen to remodel their home using healthy materials that don’t outgas or release toxins.

Up on the housetop

The first major challenge is to make a virtually uninsulated cabin energy efficient. Living in the Colorado mountains is pretty challenging in winter when temperatures can dip well below zero and winds can reach 100 miles per hour. Finding the right combination of air sealing and insulation to protect the building’s historical façade is crucial.

We started with the roof, which had recently been covered with the cheapest shingles possible. Because the attic space is now the bedroom, headroom is limited. My suggestion was to cover the existing two-by-four rafter roofing with a product that incorporates two or three inches of polyisocyanurate rigid foam with a nailing surface laminated to the top. The new polyiso foam product from Atlas Roofing doesn’t contribute to ozone depletion or global climate change like conventional polyiso insulation. Polyiso also has an R-value of 7.5 per inch, which gives the home a net roof insulation of R-35, including the four inches of insulation in the rafters. Colorado code for roof insulation is typically R-30, so this additional R-5 will make the home markedly more comfortable while lowering Tracy and Tim’s energy bills. Installing fifty-year shingles will give them long-term protection from the hearty Colorado winds and eliminate waste from more frequently replaced roofing materials.

Warming up with insulation

The next step is getting insulation under the floor. The house is built on a stone rubble foundation with a shallow crawl space underneath. Water currently flows under the cabin from the hillside above. I suggested that Tracy and Tim use water-resistant blue board (also known as closed-cell extruded polystyrene or Styrofoam) between the floor joists. The edges can then be caulked to reduce air infiltration. A laminated product made of recycled aluminum and wood fiber, called Thermo Ply, can then be installed across the joists to protect the foam from rodents and to further reduce air infiltration. The potential R-value is 24, which is significantly higher than the Colorado code standard of R-15 and will drastically improve the home’s energy efficiency. A 6-mil polyethylene vapor barrier should then be installed on top of the dirt to keep moisture away from the wood-framing members.