The Lay of the Land

“I’ve rarely been on a construction job where something hasn’t gone south,” says landscape architect Todd Richards, an associate at DTJ Design in Boulder, Colo. On one project, a huge chunk of rock stopped excavation for a pavilion. On another, the construction crew hit ground-water a couple of inches down. But in each case, with some workarounds, those setbacks were turned into site features. The pavilion was redesigned to incorporate the rocks, and the watery soil became a cultivated wetland.

These are situations that builders encounter regularly, and not every condition can be anticipated. Still, Richards says, builders should protect themselves by making sure the land is studied from every angle—ideally, well before the house is sited and designed. His job is to spot potential problems, stage the jobsite for subcontractors, and suggest ways to capitalize on its assets. Even before a piece of land is purchased, he advises clients to research its history of uses. For example, was the land ever mined, creating easements, underground vaults, or tunnels that could destabilize soils? Looking beyond the site’s borders, have the neighbors installed walls or changed drainage patterns that affect water flow across the property?

In North Scottsdale, Ariz., an existing hillside and paloverde tree serve as borrowed backdrop to the pool and reinforce the home’s desert character. The house and outdoor spaces are oriented around the naturally varied terrain. Designer: DTJ Design, Boulder, Colo. By thoroughly studying the terrain, landscape architects can also offer clues on positioning a house to optimize all kinds of conditions, from view corridors to best climate and microclimate, best exposure, and best access. Some of these things are quantifiable, some are intuitive. Taken together, they form the basis for designing a house and garden that go together. You want to place a dwelling in the right location climatically to ensure that it benefits from cooling breezes, that vegetation will grow around the house, and that the driveway functions in all kinds of weather.

Before the construction crew sets foot on DTJ’s projects, the assumption is that other relevant experts have weighed in, too. A qualified arborist and horticulturalist might be called in to assess the mature vegetation and tag plants that merit protection. They’ll also check to see whether the soil is fertile enough for landscaping and suggest ways to amend it. A biologist may be needed to study wildlife habitat. In some jurisdictions, for example, the presence of redwing blackbirds would require holding off construction until their nesting period is over.

Most important, a geotechnical engineer tests the soil composition for structural bearing issues, since a lack of knowledge can lead to wet conditions, structural failures, and sink holes. Colorado’s heavy clay is prone to shrinking and swelling, which can crack foundations. Solutions for mitigating movement usually involve amending the dirt with structural fill or setting the building on piers in bedrock. Often, parts of a site are stable, while others have 8 inches of potential swell. On a recent DTJ job, a geotechnical engineer checked five locations for the soil’s ability to support different kinds of foundations—for garden walls, the building, and terraces. While general contractors routinely examine the soil structure before building a house foundation, it’s less commonly known that driveways, swimming pools, terraces, and even some play surfaces also require below-grade investigations.

A large stand of ponderosa pines was the reference point for a road, lot lines, and a house at a master-planned community in Aurora, Colo. The wall helped to preserve the trees and made them a memorable part of the landscape. Designer: DTJ Design. “Having knowledge of all these issues and being able to pull from different sources is important,” Richards says. “Generally we can turn constraints into opportunities to give the piece of land a unique character, making it memorable.”

Wise Interventions. With the site’s assets and liabilities clearly labeled, Richards and the construction manager work out a plan that ensures everyone on the job abides by best management practices. That includes making sure protected areas are fenced off, designating other spots for the dirty work, and managing soil erosion with silt barriers. “We tell builders, ‘Here’s where you can stockpile topsoil and building materials; here’s a good location for doing your concrete wash, and here’s the expectation for how it’s done.’ Some of the best contractors we work with have a foreman who walks the site every day. It’s policing, and getting the subs to police themselves.” To put teeth into the plan, subs are fined for violations such as damaging tree trunks or compacting the ground around them. Each tagged tree has a predetermined replacement value set by the arborist. And communication continues throughout a project. When something unanticipated comes up—say a sewer line needs to be run across a gulley—a plan is developed, in writing, for mitigating the damage. “On every site there’s usually some distinctive character we need to protect, even if it’s not something beautiful or natural,” Richards says. “It might be an existing drainage structure that can’t be removed or damaged.”

Of course, all this investigation and oversight comes at some expense, and a 1-acre site might not warrant such in-depth research. But the burden is on builders to help clients focus their investment where it counts. The way Richards sees it, builders need to weigh the value of engaging a web of experts. Ask yourself: Given your experience building in a particular region, do you have enough information about the site to proceed with confidence? Either way, clients will appreciate the heads-up about how land issues might affect the construction budget. “The builder might introduce it contractually to the client—here are the services we can include, here are the benefits—and let them make that decision,” he says.

Mature live oaks established the finish grade of the pool at this Austin, Texas, community. Nearby is the clubhouse, which took elevation cues from another stand of trees. Designer: DTJ Design. Richards’ philosophy is that every condition—whether it’s perceived as negative or positive—contributes to the site’s overall character, and he counsels clients to avoid thinking of emerging issues as headaches. “Every custom home client wants their property to be one of a kind,” he says, “and a reading of the site is a good place to start.”—Cheryl Weber is a writer in Lancaster, Pa.