Sitework and landscaping are typically the first and last tasks, respectively, on a building site. Steps can be taken at the beginning of sitework that can increase the value—and reduce the cost—of landscaping after construction. Siting of the building itself usually has already occurred, but there is still often an opportunity to influence issues such as solar access and strategies for minimizing site disturbance.
Protecting vegetation and other key features
A site survey should precede any sitework to identify sensitive areas and features to be protected, such as wetlands, trees, and other vegetation.
- It’s well worth the effort to save trees if they are healthy and not too close to the structure. Mature trees on a lot can add more than 15 percent to the value of a house, and appropriately placed trees can reduce a building’s conditioning needs by more than 40 percent.
- A tree’s root system extends quite a distance from the trunk—typically at least to the drip line of the farthest branches. Even just compacting the soil can harm the roots, so a large area around each protected tree needs to be fenced off. To ensure cooperation of subcontractors in this effort, one strategy is to specifically list in their contract the value of each mature tree and hold them responsible for that value if the tree is damaged.
- Invasive plants introduced from other parts of the world can wreak havoc on the ecological balance of a region, so nonnative species should generally be avoided in landscaping (though noninvasive exotic species—those that don’t spread and outcompete native plants—are less of a concern).
- Plants that are native to your area are also adapted to your climate, so they tend to need less care and maintenance, and require less watering—saving time and money. Most lawns are planted with nonnative turf grasses, such as Kentucky bluegrass, which require watering in most U.S. climates. Hardy, native species such as buffalo grass and certain fescues should be used instead, or lawn areas should be replaced with other landscapes that require less water, fertilizer, herbicides, and maintenance.
Designing for stormwater runoff
Handling stormwater runoff can be a major design issue. Conventional solutions include concrete or PVC drainage pipes and, on larger projects, detention ponds. These remedies are expensive and tend to increase the contamination of the water from surface pollutants.
Softer solutions include the use of pervious surfaces to allow rainwater infiltration directly into the ground. These solutions are far better environmentally and usually less expensive. Use of swales for rainwater instead of curbs and stormwater drains is also preferred.
Preferred sitework products
Resource-efficient products and building materials for sitework and landscaping include porous pavingA paving material that allows rainfall to percolate through and infiltrate the ground, rather than contributing to stormwater runoff; can be asphalt, concrete, or porous grid paver.
systems suitable for driveways, walkways, courtyards, and parking areas, and landscaping timbers made from recycled plastics, which are more durable in ground contact than preservative-treated wood. Retaining walls and hardscape surfaces can often be made from salvaged materials, such as broken up concrete paving (which some green builders refer to as “urbanite”).
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