Wood is Good

June 1-September 13: Working with wood “for show” is rewarding and I spent many pleasant days sealing 1×4 pine boards for the soffit and 1×8 pine boards for siding. By the time my crew showed up, I had an impressive stack.

bestWe started on the underside of the roof overhang, and hit on what might be an original idea—spacing the 1×4’s apart the width of a nail to create an integral vented soffit. The corners turn like a woven basket.

goodMost modern homes or remodeled homes have unremarkable “punched tin” soffit panels or metal strips. So unremarkable that I bet most people (not counting architectural snobs like me) take no notice. Look at a historic home and you’ll see boards—often with a interesting pattern or molding added.

Code requires roof venting where fluffy, air-permeable insulation like fiberglass or cellulose is used. Impermeable sheet foam or spray foam doesn’t need venting. The idea is that if warm moist air from the living space penetrates the attic or roof cavity, it can escape. The slots in my soffit will supply more than enough air flow through the 3” deep vent chute we built back in April (see blog post “Vent Chute”).

I shopped around for siding. Cedar is naturally decay-resistant but pricey. Rough-sawn wood in any species looks great and holds a finish better but also costs more. I looked at locally milled wood and visited several Amish farms. I trolled Craigslist and called up area lumber yards. The best deal I found was from Cedar Direct, just a few miles down the road. They import white pine from forests in British Columbia that are certified SFI (Sustainable Forestry Initiative) or from Central Oregon forests that are “selectively harvested”—not clear-cut. The price was right and the quality was good. Delivery was DIY.

I sealed the the boards with PolyWhey, a water-based sealer derived from whey—a byproduct of cheese making—from Vermont Natural Coatings. Whey is a natural bonding agent that displaces the toxic ingredients found in more common polyurethane. The manufacturer claims their product contains up to 45% renewable ingredients and is made in a plant using 50% renewable energy. When applied, it creates a non-toxic waterproof barrier, and protects again UV degradation, mold, and mildew. I found it easy to brush on, easy to clean up, and had virtually no odor. The matte finish lets the grain and coloration of the pine show through without a plastic-y look.

PolyWhey is ultra low VOC (volatile organic compounds) and meets “CA Prop 65”—the toughest environmental standard now in force in California. The standard disallows any product that contains any of the 900 chemicals that have been linked to cancer, birth defects, or other reproductive harm. PolyWhey also complies as Red List Free—a worst-in-class list of materials found in the building industry.

I ordered the sealer in 5 gallon plastic buckets instead of 1 gallon plastic containers. It wasn’t less expensive this way but I knew I could always use another bucket. Plastic containers are, in theory, recyclable—though as many of us are learning, it’s not so easy to find a facility that takes them or may take them but landfill them.

Leftover product isn’t classified as hazardous waste, and can be dried and discarded—but it’s not clear where. Because I sealed the boards before the crew chop-sawed them to fit, I have quite a few cut-offs. I contacted the manufacturer about burning or landfill. The rep admitted there isn’t any official recommendation, but said he personally would without hesitation burn them in a camp fire. So thats what I’m going to do.

cut offs     I hope the fresh appearance of my pine lasts a long time, but of course no one is going to hand me a guarantee. The USDA publication “Build Green: Wood Can Last for Centuries” points out that when wood is installed properly, it doesn’t deteriorate. Decay can be prevented. The culprit is fungi who attack the cell walls of wood in the presence of moisture, air, and favorable temperatures. On siding, we can’t control air or temperature, but we can control moisture.

My wood siding counts as a sustainable choice if I can keep it dry and on the house for a long time. I can’t control the needs or whims of a future owner, but here’s what I can do as the original builder:

  1. Apply water-proof sealer to clean, dry, freshly milled (not exposed to UV) wood on 4 sides prior to installation and to field cuts (end grain) during or after installation. This repels rain and limits wood movement like cupping, splitting and popped nails.
  2. Install siding with tight joints and caulk or flash all penetrations. Use bevel cuts at splices and cut any horizontal trim at a slope to shed water.
  3. Eliminate trees or large shrubs next to the house that cast shade and block air
    movement (both slow drying and encourage mold, mildew, and pests).
  4. Provide generous roof overhangs, kick-out flashings, and hold siding away from grade to prevent splash-back (my pine siding starts 32” from grade, above impervious cement board lap siding).
  5. Hold siding off roof surface to prevent wicking from snow melt.
  6. Shut down bulk vapor drive by air-sealing each and every penetration through the wall at each layer of material and use vapor-permeable materials to slow or store but not stop vapor transmission where appropriate.
  7. Install a Heat Recovery Ventilator to maintain optimal indoor humidity

But why go through all the work and worry when I could chose vinyl, steel, aluminum, wood composites, stucco, or brick? All have positive attributes, and promise low-maintenance. Vinyl is the least expensive and most common siding here in the Midwest, and many in the green building community argue its environmental impact isn’t so bad, even though it depletes fossil fuel reserves and uses a slew of chemical additives. It sheds water well, is inherently “back-vented” to allow the wall behind to drain and dry, can last 40 years, can contain some recycled content, and can be recycled (though most tear-offs still land in a dumpster). Here’s a good article: Pro/Con: Vinyl is Green.   And here’s another take on it: The Seven Deadly Sins of Vinyl.

Wood is abundant, renewable, low-tech, and requires far less energy to make than metal or cement-based siding products. It can be a source of local jobs and spur on a more regionally-based economy (more on this in a future blog post). Its disposal doesn’t place a burden on future generations. What will our post-post-post industrial society look like in 2060 when today’s vinyl siding or steel is slated for recycling?

Each homeowner has their own preferences, place value on certain architectural features but not others, and bet on different products. Each building material we use has environmental costs associated with their material extraction, manufacture, transport, and disposal—but there is no difinitive source that tells us its durability or carbon footprint “score”. There are just too many variables.

20190913_124324Green building usually means reducing operating costs by adding layers of insulation and products like high-performance windows. But today, more attention is being paid to the carbon footprint of the products themselves—especially as climate scientists warn of an ever narrowing window of opportunity to reduce our carbon emissions. Does it still make sense to build an uber energy-efficient home if the materials used cause more climate disruption today than the cost to heat and cool the home over these next, crucial years?

Alas, the best choice is to not build at all. Refuse, Reduce, Reuse, Recycle. More on this in a future blog post.

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