Job Sites

Bird's-eye view

Recycling and waste reduction are two priorities on a green building site.

We don't have to generate the tons of trash typical of most job sites

Reducing waste is not a high priority on many job sites. An average new house produces tons of waste, which is usually thrown in a dumpster and carted away when the job is done. Reducing potential waste and recycling as much as possible helps lower costs and reduce the environmental impact of construction. In some instances, building materials salvaged in one phase of a project can be used in the next.

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AN INTEGRATED APPROACH TO CONSTRUCTION
FURTHER RESOURCES

Use less

Frame smarter, use less

Reducing material waste begins in the house's planning stage. Use standard material dimensions and layouts that maximize the use of each material and minimize cuts. In general this requires using a 2-foot design module where the side of the house parallel to the primary joist span is evenly divisible by 4 feet and the length perpendicular to the primary joist span is evenly divisible by 2 feet.

One of the most important strategies for reducing the amount of framing lumber in a house, called advanced framingHouse-framing techniques in which lumber use is optimized, saving material and improving the energy performance of the building envelope. or optimum value engineering (OVE), has the added benefit of improving a building’s energy performance.

OVE typically uses 2x6 studs on 24-inch centers rather the traditional 16-in. o.c. Increasing the stud spacing in the floors and walls can eliminate approximately one-third of the lumber compared to 16 in. o.c. framing. A traditionally framed house also has redundant framing at doorways, windows, and corners. By calculating the actual load requirements, an OVE-framed house properly sizes headers in bearing walls and uses single plates, two-stud corners, and ladder blocking at interior/exterior wall intersections. OVE also eliminates cripple and jack studs and headers from nonbearing walls.

Reducing the amount of framing lumber increases the insulation in the walls and allows fewer opportunities for thermal bridgingHeat flow that occurs across more conductive components in an otherwise well-insulated material, resulting in disproportionately significant heat loss. For example, steel studs in an insulated wall dramatically reduce the overall energy performance of the wall, because of thermal bridging through the steel. .

While 24-inch centers and careful engineering help reduce the amount of wood used to frame a house, there are also a couple of ways to reduce waste from offcuts and errors:

• Generate detailed cut lists from the plans.
• Use some variation of prefabricated construction. At the extreme end of the scale is modular prefabricated construction. This technique not only eliminates waste at the home site, it minimizes waste at the factory site because of the standardized production framing that uses offcuts in other modules.

Factory-built components on a smaller scale than modular construction also reduce waste. This includes engineered floor and roof system (trusses) and panelized construction where wall, roof, and floor components are ordered, cut, and assembled in a factory and delivered to a job site where the pieces are assembled. SIP(SIP) Building panel usually made of oriented strand board (OSB) skins surrounding a core of expanded polystyrene (EPS) foam insulation. SIPs can be erected very quickly with a crane to create an energy-efficient, sturdy home. panels are another variety of panelized walls and roofs that eliminate studs and most job-site waste while creating a very tight, well-insulated envelope.

Grind it

Chew it up to facilitate other uses

Grinding trees and brush into woodchips for use as mulch is preferable to carting the debris to a landfill. In 1999 the National Association of Home Builders Research Center estimated that home construction produced 1.3 million tons of solid-sawn wood waste. Clean wood waste—not painted, stained, pressure-treated, or laminated products—can also be turned into mulch.

Spread over the surface, mulch helps soil retain moisture and moderate its temperatures, and adds nutrients to the soil as it decomposes. If you add chipped wood to the soil, plow it under. Although wood chips help aerate the soil, their high carbon and low nitrogen content can actually tie up nutrients and affect the health of the top layers of soil. You should check out this option with a local soils extension agent.

Job-site grinding of gypsum board for on-site use as a soil amendment is another option. Gypsum is commonly used to improve soil tilth, and research has shown that clean gypsum board cut-offs can be ground for exactly the same benefit.

Packer Industries, a Building America partner, produces job-site grinding equipment that can handle several types of common construction-site waste materials, including wood, gypsum board, roofing shingles, and even cement block.

Recycle it

Don't just throw it out

Consider recycling these four materials:
• Clean wood waste, which can be used as fuel at some wood-fired electric power plants and as a bulking agent in large-scale composting operations.
• Gypsum drywall cutoffs, which can be recycled; and, while the practice is not yet widespread, more and more drywall factories are recycling waste drywall into their product.
• Recycled roof shingles, to be used in roadways as asphalt pavement, aggregate base, or cold patch.
• Cardboard boxes and packing materials, and beverage containers, which should be recycled on the job site just as they would in a household.

The key to successful job-site recycling is a detailed plan posted so that everybody knows what is expected. Separating materials into clearly marked recycling streams is important. Each recyclable material should have its own receptacle. Another strategy is to forgo the Dumpsters and use piles surrounded by fencing for each recycled material. Then everybody can see what is being thrown away, and where.

Most of the materials found in a Dumpster at a typical construction site can be recycled, but make sure you or your hauler has identified markets for each material beforehand.