Cover story: How big is too big?

Make a large hole in the ground and line it with concrete and there will be impacts. It may interrupt an underground stream and cause it to find a new path. Excavated soil being hauled out in 12-ton dump trucks will affect the roads, bridges and traffic, and may annoy neighbors who must endure their passage.

But the property owner pays road-impact fees, and tolerant neighbors may count on neighborly tolerance when they build their own basements. The town will see higher tax revenues when multi-functional basements add assessed value. What’s the harm of people living, sleeping and entertaining themselves underground, of using tunnels to get from basement to basement? With the moderate temperatures that prevail underground regardless of season, the living is environmentally efficient.

These are among the arguments being made in defense of Woodside residents’ current freedom to build a basement of any size more or less anywhere. The town’s basement regulations, last revised in 1995, were handled almost as an afterthought, Planning Commission Chair Marilyn Voelke told the council in April. Recent proposals include huge and sophisticated subterranean facilities.

In keeping with the town’s general concern over the environmental impacts of such projects, the Woodside Town Council is considering restrictions on size and location. Woodside’s relative lack of basement regulations is uncommon among towns with similar demographics, according to Ms. Young’s staff report.

Portola Valley, Atherton, Los Altos, Monte Sereno and Saratoga restrict basements to mainly under the footprint of the above-ground building, according to the report.

A Woodside council subcommittee will present recommendations for regulations on July 14. At a study session in May, council members Peter Mason, Ron Romines and Dave Tanner gave a preview:

● Basement size should be tied to zoning and equal to the maximum allowable size of the main house: 3,000, 4,000 or 6,000 square feet, assuming a 12-foot-deep cut into the earth. A deeper basement would require a reduction in square footage.

● No more than 50 percent of a basement could extend beyond the footprint of the above-ground building.

● All basements would require a geo-technical and hydrological analysis.

● Basements in general should not be allowed in setbacks or within 10 feet of property lines, unless they’re under structures that predate the new setbacks, but they must stay within the above-ground building’s footprint.

Guidance needed

The state of basement regulations in Woodside reflect a mismatch between the town’s guiding documents and its specific rules, town officials have said. The general plan and residential design guidelines were updated in 2012, and offer strong conceptual support for the value of “rural character” in Woodside and living in ways that respect the land and its wild inhabitants. But the language in the municipal code from 1995 does not reflect that view.

Helping a project applicant find a way through this contested territory is the task of the Architecture and Site Review Board and the Planning Commission, which are entrusted with guarding Woodside’s character.

The town received 40 basement applications from 2009 to 2014, but 20 so far this year, according to town statistics. In April, Ms. Young asked the council for an urgency ordinance to permit conventional basements only one story directly beneath a main residence while the council and staff worked out new regulations.

The council voted 5-2 in favor of the ordinance, but with six votes needed to enact an urgency ordinance, it did not pass.

Ms. Young’s report described a selection of basement plans, including one of nearly 14,000 square feet with a six-car garage, three bathrooms, bunkroom, two powder rooms, family room, media room, exercise room, massage room, office, pantry, wine cellar, storage area and inside-outside courtyards.

Another was 9,500 square feet with a garage, three mechanical rooms, wine cellar, audio-video equipment room, laundry, lounge, two powder rooms, storage room, bowling alley, sitting room, recreation room and sunken courtyard with an exit stairway.

Rural character? The ASRB, as council members have said, has the task of giving guidance to applicants on tailoring a project to town standards, but not crossing the line and participating in the design. The ASRB requested guidance on basements.

Criticism

A group of about a dozen Woodside residents, represented at council meetings by Greg Raleigh and Richard Draeger, hired a consultant to prepare their own analysis of what the town should do.

Among the conclusions listed in a draft of that analysis:

● The town should “encourage rather than discourage” uses that save energy or “improve rural aesthetic and open property areas.”

● Basement square footage should be tied to total allowable floor area for the parcel, not the maximum allowed for the main residence.

● The regulations should not require a basement to located under a structure.

Mr. Raleigh is planning a modest basement with a wine cellar. In an interview, he discussed several points, including insufficient attention given to the benefits of basements. Because they’re underground and easy on air conditioning and heating, they should be encouraged, he said.

“Don’t harm property rights or individual rights when there’s no harm to the environment or the public good,” he said. As for big basements, “Tell me what the harm is and then I’ll have an opinion,” he said. Someone with 30 acres may want a large basement, and it would be environmentally friendly, Mr. Raleigh said. “Why would we stop them from doing that?”

Councilman Tanner, a contractor and builder, agreed that basements do have environmental benefits, but their greenhouse gas footprints involve more than just stable interior temperatures.

Basements embody the manufacture, transport and use of tons of steel and concrete, heavy trucks to haul off soil, and the basement’s eventual decline as moisture finds it way inside, Mr. Tanner said. In the end, huge structures are harder to sell and may eventually be abandoned, he said.

Mr. Raleigh argued that increases in property tax revenues will “more than pay for” damage to roads. Dump trucks are admittedly an inconvenience, but people have a right to develop their property, he said.

Councilman Mason described Woodside’s roads and bridges as “very fragile,” and said that the costs to repair them cannot be recovered from a residential project. “We’re not trying to hurt anybody’s ability to do a basement,” he said. “We’re just trying to say that there’s a limit to its size.”

Mr. Raleigh returned repeatedly to the idea that regulations could be unfair to owners of smaller properties who are cramped on space and remodeling funds. Without the money to elevate an existing house, and with restrictions on basements beyond the footprint of the main house, the resident could be forced to compromise. For example, instead of a wine cellar and a garage below ground, it would be one or the other.

Woodside’s general plan, Mr. Tanner said, reflects a town that aims to be one with nature and not to modify nature. “We’re not saying don’t build a basement. We’re talking about the size of a basement,” he said. “If you have four acres, do you have a four-acre basement? How big should a basement be? … If we don’t have rules for it, somebody is going to do it.”

“We elect council members hoping that they’ll watch our back,” Mr. Raleigh said in conclusion. Underground construction doesn’t have aesthetic, privacy or fire hazard impacts, he said. “How do we help the community or the environment (by depriving) that owner of the right to have a basement?”