FAVORITE MATERIALS – PART 1 – EXTERIOR

I typed “green materials” into Google this morning and got 13,400,000 results. If I took 30 seconds to look at each entry, separating the relevant from the absurd, dedicating 12 hours of every workday, I’d have a couple dozen years of research ahead of me. In our work, sustainable, economical, and regional choices are critical to our projects’ successes. Some strategies reoccur; the Locus favorites. This post is the first of several outlining materials and strategies we return to time and again in our green buildings. You might save yourself 35 years of research by spending 5 minutes here.

1. Steel siding and roofing. Unfinished, coated, or treated steel can show up at a jobsite just about 100% post-consumer recycled product (more often than not, it will have at least 60%). It is recyclable at the end of it’s useful life span. It’s very durable, most systems are easy to install (I’ve personally installed one or two over the years), and can last 50 years or more. Find an asphalt shingle that can do that! For roofing, it is generally our first choice. On a few recent projects, we’ve used Cor-ten or “weathering” steel as siding. The siding corrodes to form a protective layer with a look not unlike brown leather. This one is in Northfield.

Corrugated Cor-Ten Siding

2. Black Locust. Black locust is widely considered to be a weed tree. However, it is locally available where we are in the upper Midwest, grows quickly, is extremely tough, is suitable for exterior use (ranchers used it for corral fence posts), and weathers to a grey similar to that of cedar and redwood. It can be hard to find, but we’ve had luck sourcing it with small, family-run, lumber mills in Wisconsin. It is sometimes called the “domestic exotic” wood. We used it here as a screen and window shading device.

Black Locust Scrim

3. Solar thermal systems. We feel solar thermal is the best “active” energy generation system for residential and small commercial projects (where we have unshaded solar access). Payback times can be relatively quick with tax breaks and credits, and systems can be integrated with radiant floor heating, domestic hot water, radiators, and sand-bed heat sinks. Locally, we’ve worked with IPS and Energy Concepts for engineering and installation on projects such as this one.

Farmhouse solar thermal array with windmill

4. Solatubes. This is half mini skylight, half light fixture. The kit consists of a small dome atop the roof, a highly reflective tube, and a finishing trim similar to that of a recessed light. During the day, one or two Solatubes deliver ample natural daylight into an interior stairwell, hallway, or windowless bathroom; enough to skip flipping a switch. I’ll admit, we were skeptical of Solatubes until we tried one.

5. Spray insulation. These wall cavity foams, a substitute for conventional fiberglass batt insulation, come in closed and open cell varieties, each with pros and cons. Closed cell systems are considered to involve more toxic manufacturing processes, but have better thermal resistance, saving more energy over time. Open cell varieties are considered more benign and allow walls to breathe, but have only 60% of the resistance of closed cell. We’ve used many of them, including bio-based foams. They virtually eliminate convective movement, silence exterior noise, and can help to curb condensation problems in cold climates. Different projects suggest different products, but foams beat fiberglass hands down.

6. Green roof. For a flat roof, a green roof is our preferred way to go – if budget will allow it. It’s certainly more attractive than a built-up or membrane roof, lasts longer, slows stormwater runoff, improves air quality, may reduce energy use, and provides a little chunk of habitat. More benefits at www.mngreenroofs.org/benefits

7. Recycled Content Shingles. If a flat roof alarms you, and metal isn’t your bag, look at “mudflaps“, our slang for recycled mock-slate and mock-shake shingles, such as those manufactured by EcoStar. These shingles are manufactured with 80% post-industrial waste, and are available with a 50-year warranty. We used them on this house in northern Minnesota.

Mock-Slate recycled plastic shingles

8. Polycarbonate. There is already a detailed post on the blog about polycarbonate as an exterior skin. Link to it here. This is another recent project of ours.

Translucent polycarbonate siding

9. Recycled Plastic Chairs from Loll Designs. When the siding is up, windows in, roofing on, and landscaping is finished, finish off your exterior with a couple of chairs and an ottoman from Loll Designs from Duluth. It’s 100% recycled post consumer HDPE catching your back.

Recycled Chairs from Loll