From The Ground Up

I have a client. Since looking at the property in Santa Cruz last year things had been slow. But I've been seeing sure signs of economic life coming into bloom. People aren't as shell shocked about life as they seemed last year. All the fear that was poured into society didn't poison the well. The most common response to all the dire predictions that I saw, and I traveled a lot last year, was the planting of gardens. Everywhere I went I saw people building raised beds and turning compost into the soil. I thought "What a marvelous response. I'm glad I live among a people of such grace". As Voltaire wrote "We must all tend our gardens."

This blog, by the way, has been very effective at getting information to people who are interested in actually building. My new client is a guy that retired from the petroleum processing business and lives for at least part of the year in Panama. He owns a piece of land in a community called Bethel Island on the Sacramento River delta in northern California. He and I are into about a 250 email relationship at the moment. We exchange drawings using Google Sketch Up and have produced a design that's ready to develop.


This is the building site, the view is looking back at the island from the top of the levee. The lot is 50 feet wide and about 200 ft long from the levee to the road. There's a drop of about 5 feet from the road to the lowest spot on the property. From the road height to the top of the levee is 16ft. The design that we are working on is three stories tall. We are using two stacks of three containers with a span of 16 feet between them. The span connecting the stacks is built of structural steel and glue laminated beams. The first level contains the garage and will lift the habitable parts of the building above the flood level. Most other houses on the island are built on top of pilings to raise them up, we are going to use hi cube cargo containers that sit on grade beams which are in turn set on helical piles.

When I visited the site for the first time I met with Steve from the Bethel Island Municipal Improvement District. He is in charge of maintaining the levee and is the first authority that must approve building plans. I asked him about the soil conditions and he said "So you don't know already?". This is always a very bad sign. He explained that below the topsoil was a layer of peat moss that was on average 32 feet deep. Peat has the consistency of a wet sponge and is so unstable it cannot be built on. Below that, however, was a bed of compressed gray sand that would support piles. Pile driving, as you might imagine, is very expensive in itself. But when you add the associated costs of civil, soils and structural engineering just to get you to a workable design the costs really add up. Steve did say that it was legal to build on a concrete slab directly on the ground but then pointed to a neighbors garage that had been built a couple of years before. The garage was nose diving about 5 degrees already. He added that the soils subsides about an inch and a half a year.



And so it's time to start the site work. The house is designed so that the habitable space starts close to the level of the top of the levee. The whole point of building here is the proximity to the river. Almost every house on Bethel Island is built along the levee, each with it's own dock. The building code dictates that no building can be higher than 35 feet from grade. Say the gray sand layer is currently 34 feet down. You start this process by hiring a soils engineer to bore test holes in the ground to determine the depth of the bed that you can build on. As every house on the island has had to do this you would think that this depth was a known quantity. The short answer is no, the process has to be repeated with each job. I've asked for proposals from two firms that have some experience of the island and am waiting for the bids. They will show up with a quote for the report plus whatever it costs to bore the holes. There are several methods to do the drilling and each has its own draw backs and features and they are all expensive. In the next installment I'll be discussing what we find. I'm willing to bet you right now that the learning curve is going to be sharp and expensive.