Rural green building rules allow greater flexibility


New alternative regulations for those seeking to build more sustainably in rural Marin, approved last month by the Board of Supervisors, could lead to an easier path for people building their own homes and for those who want to use materials like straw bale or cob.

The new buildings codes contained in the amended Title 19 are voluntary, meaning that applicants can opt-in, starting in October. They create greater flexibility for owner-built rural dwellings, for converting commercial spaces to both living and work quarters and for using straw bales for both insulation and load-bearing walls. They also create a county architectural commission and alternative regulations for architectural structures and features deemed significant by the commission. The overall goal is to pave the way for the use of materials like cob or reclaimed wood that don’t have standardized measurements for determining precisely how much support they provide, unlike metals and graded timber. 

“What the ordinance really does is to facilitate the use of alternatives much more easily than would be possible without this ordinance,” said Bill Kelley, the county’s deputy director of building and safety. 

Though it doesn’t guarantee that any given project will be approved, the code provides “many, many shades of gray” so the building department can approve projects that would be virtually impossible under Title 19’s current black-and-white approach, Mr. Kelley said. 

For owner-built rural dwellings, for instance, the new code says the intent is “to permit the use of ingenuity and preferences of the builder, and to allow and facilitate the use of alternatives…to the extent that a reasonable degree of health and safety is provided by such alternatives.” 

It also allows buildings to confine electrical outlets to a single room and it eliminates requirements that such outlets occur every 12 feet around a room or every four feet along a kitchen counter. 

Turning a commercial building into a joint work and living quarters, which the county says could help reduce the carbon footprint from commuting, will also be easier, Mr. Kelley said. Typically, converting such a space into residential use requires bringing all aspects of the building up to code. The new ordinance, he said, provides more discretion and an easier path for approval.

The Title 19 amendments also allow the building department to more easily approve the use of alternative materials like straw bale and cob; those materials weren’t completely banned under the current code, but if contractors or architects wanted to use them, they had to prove precisely how much weight they could bear, in what Mr. Kelley called a “fully engineered approach.”

Paul Korhummel, an architect who has lived in Inverness since the 1970s, said he started out his career focused on highly sustainable materials but abandoned them because of the near impossibility of getting them approved for use. Building codes, he said, have been dictated by engineers who prefer more standardized materials. “I’ve really moved away from alternative building techniques because it’s too problematic,” he said.

The ordinance implements prescriptive guidelines for straw bales, an energy efficient substitute for conventional stud-bearing walls, as both insulation and as load-bearing walls. Moisture levels must be measured with a special tool to prevent rot—a particular problem in foggy West Marin—among a host of other regulations that limit their height, size and compression. 

Though there are no such guidelines for any other alternative material, Mr. Kelley said things like cob or reclaimed wood will also be easier to use under the guidelines. He noted that cob, a mixture of water, earth, clay and a binding material like straw, is one of the best materials for those looking outside conventional building. “Cob is a site-derived material, which is what makes it so incredibly sustainable, but there’s also a lot of variation in material—what you dig out of your backyard would be different than what I dig out of my backyard,” he said.

Since the ordinance doesn’t have prescriptions for cob, applicants would have to find a way to prove the proposed structure’s relative safety. But they wouldn’t necessarily need hard-and-fast engineering calculations. “We would not be concerned with applying state code standards. What we’d ask instead is to show us that it’s safe and fire resistant.” 

How do you prove that? “Ask me a year from now,” Mr. Kelley quipped. “I’m anticipating some people will apply for cob under permits, as opposed to building without a permit, which is probably what is happening now.” He added that the new ordinance could “open the door” for someone to develop a template for cob similar to that for straw bale.

Jim Campe, a retired architect in Inverness who lives in a house he designed with passive solar heating, said that one of the biggest roadblocks isn’t only what is or isn’t allowed, but the cost of permits. (He also noted that a major part of so-called green building has to do with how one lives within it. Back in the 1970s, when he built a house in West Marin without much insulation, “We were very comfortable, because we put on coats when we got cold,” he said.)

Mr. Korhummel agreed. “Right now it’s not just the sustainable component but the affordable component,” he said.

Building permits alone for single-family dwellings can top $10,000 depending on square footage, and that doesn’t include the cost of a coastal permit and other fees.

Mr. Kelley said that though permit fees cost the same under the new guidelines, they would become less expensive if they end up requiring fewer staff hours. “If it turns out, over time, that the alternate building code projects under this ordinance reduce the amount of time we need to spend [on review], we would need to amend the ordinance in the future to lower fees for this class of permits…It’s not only a possibility, but it’s a mandate, because we’re subject to user fees laws from the state.”

Some of the more innovative aspects of the ordinance, according to Mr. Kelley, are the provisions that create a county architectural commission that can designate and protect existing structures or even plans deemed architecturally significant—such as designs with a minimal carbon footprint. “[T]his has the ability to safeguard and protect and preserve designs by the next generation of Frank Lloyd Wrights,” Mr. Kelley said.

But that will push at the limits of the ordinance, since those designs could include features like composting toilets that are not only unpermitted in Marin but under the jurisdiction of environmental health, not the building department. (The head of Environmental Health Services, Rebecca Ng, said she didn’t see compostable toilets becoming permittable any time in the near future.)

“We’re at a disjoint [in some ways] because the local regulatory process is comprised of different divisions,” Mr. Kelley said. “We’ve taken a more isolated approach. What would help us, if sustainability is our goal, is a more holistic approach to the design and construction itself. But we have to go from where we are.”