How do we build more homes here?

But for the sake of discussion, let us consider a proposal I heard once from one of the county’s most influential builders: Why not take just 10% of that available open space and build housing? It is almost impossible to know how much space that will provide for housing, but implicit in the question is the notion that we would hardly miss 10% of our open space and the trade-off in solving the housing crisis would be more than adequate compensation.

The question, of course, is the answer. We will never do that. There are major swaths of the county — Foster City and Redwood Shores chief among them — that were built by filling in the Bay. That will not happen again.

Our open space is our escape hatch, our therapy and, for many of us, both the reason why we want to live here and why it costs so much. As Nancy Pelosi once said in a related context, preserving our environment is not an issue, it is a value. We can assume there will be no desire to take away even 10% of the space we treasure so highly.

The open spaces are available for everyone, which is more than you can say about the developed spaces. This is one of the themes being emphasized during Affordable Housing Month in San Mateo County and throughout the Bay Area.

Over the last few days, I attended a couple of Affordable Housing Month activities, including a tour of model developments. Counting a ribbon-cutting at the Firehouse Square project in Belmont, we were presented with seven recent projects that added 811 units to the overall housing stock. San Mateo County has about 280,000 total housing units.

By the way, these affordable housing advocates are uniformly earnest, creative and admirable, but they have to start using more meaningful terminology. Housing is such a cold term, as is unit. These are homes. As state County Chief Executive Mike Callagy said at one of the events, these projects give people “a roof over their head, a key to their own door.”

Housing sounds like warehousing and units sounds like a production line.

As for affordable, what does it really mean? In the context of the affordable housing advocates, it means people who face no housing at all. The majority of homes being shown at the recent activities are for people whose income ranges from 30% to 80% of the county median — roughly $40,000 to $150,000 a year. It is no longer a surprise how many school teachers qualify as low-income residents.

Someone who pays $2 million for a suburban tract home (that in any normal place should cost $750,000) does not have an affordable housing problem. Until their children have to move away because even with a professional career and two incomes, they cannot pay the prevailing prices.

Housing Leadership Council Executive Director Evelyn Stivers said at the Firehouse Square event that it takes three things to make affordable housing possible — leadership from local officials, great sites and money.

Great sites can include the final product. On the housing tour, we saw spiffy new apartment communities. A drop in the bucket.

Most of these developments were three or four stories. One or two, in Redwood City, of course, were five or six.

Great sites, by definition, have to include places where a project can be built without a war of attrition by neighbors who want to preserve the character of their community, another way of saying no to change of any kind.

Open space might be sacrosanct; maybe not neighborhoods.

MidPen Housing President Matt Franklin asserted there is more than enough in-fill space in the county to build meaningful amounts of new residences without invading the open space.

But, he acknowledged, those now-underutilized spaces — most prominently on El Camino Real — would best be served with building heights that are unacceptable to most elected officials. This is where the change will have to come, and is likely to be forced on local cities by legislation that takes these decisions out of their hands.

Resolving the wider crisis of soaring and disrupting housing costs may require a new mindset: Go up, or go nowhere.

Mark Simon is a veteran journalist, whose career included 15 years as an executive at SamTrans and Caltrain. He can be reached at marksimon@smdailyjournal.com.