by Jeff Binder
Wednesday, January 2, 2008

Editor’s Note: This is the first of three articles on practical, cost-effective, green building techniques. To read the next article in the series, click here.

A recent study points out that builders overestimate the cost of building green by over 300 percent.

They tell clients that their new, green home will cost 17 percent more than a traditional one—when the actual increase is closer to 5 percent.

This is understandable. Doesn’t it sometimes seem as though we only hear about how much more it’s going to cost to build homes that offer higher indoor air quality, don’t deplete natural resources or contribute to greenhouse gases?
Architect Gwynne Pugh of Pugh + Scarpa Architects believes that the vast majority of green practices cost no more than traditional ones, and it’s the last “extreme green” 15 percent that pile on cost. “It’s actually less expensive to use the sun’s rays to heat water than produce electricity through photovoltaics, but which one is sexier?” 

Listed below are our first five picks for lower cost, green building techniques.

1. Reduce the Use of Framing Lumber

At 16 inches on center, most houses are over-engineered. Increase on-center spacing to 19.2 inches or 24 inches—and follow a few other Advanced Framing Technique (AFT) ideas and the savings can be substantial. Strategic reductions in framing lumber save money and leave more room for insulation. AFT, developed decades ago by the Forest Products Laboratory and the National Association of Home Builders*, is a proven way to use less lumber, yet many builders don’t follow its tenets.

Dimensional design is another waste-reducing measure—building to the common 24-inch sheet stock module generates far less job waste. Engineered lumber like Glulam beams and I-joists offer higher quality, strength and dimensional stability than solid sawn lumber. Aligning floor, wall and roof framing members directly in line—distributing loads evenly—allows the use of one top plate rather than two. Creating two-stud corners and eliminating horizontal blocking are other AFT innovations.

According to the Department of Energy’s Office of Energy Efficiency and Renewable Energy, fully implementing advanced framing techniques can result in materials cost savings of about $1,000 for a 2,400-square foot house and labor cost savings of between 3 and 5  percent, not to mention annual heating and cooling cost savings of up to 5 percent because of better insulated walls.

2. Recycle Job Waste

Up to 30 percent of the solid waste in landfills is construction and demolition debris, and it’s getting more expensive to dump it there. A growing number of states are mandating reduction in landfill consumption (50 percent by 2008 in California) and putting teeth in their measures by raising fees. Those costs aren’t coming down, and that makes jobsite recycling an important area of focus for builders looking to cut costs.

There are three ways to approach jobsite recycling: on-site separation of materials, construction-phase-based pickup and commingling for later processing at a recovery facility. A growing number of recycling-specific hauling companies are available, like Clean It Up Mark! in Portland OR. Founder Mark MacGregor claims builders can save up from 15 percent to 25 percent in disposal costs.

MacGregor charges a per-square-foot-fee:  about $900 for a 2,000-square foot house. He estimates that for the same house, traditional haulers would charge about $1,200, based on a $350 to $400 base fee, plus a tonnage overage. That might take three or four dumpsters full, at $350 or $400 base fee, plus an overage on the tonnage—$1,200 is not an unreasonable assumption. 

In a 1993 study for Metro, the Portland municipality, MacGregor found that in a 3,500-square foot house, wood accounted for 65 percent of the waste, drywall for 23 percent, cardboard for 3 percent and metal for 1 percent. “This year, we’ll achieve near 100 percent recycling of C & D waste,” says MacGregor. 

3. Recycle a Factory Building

The most sustainable form of building is adapting one that exists already. Builders who recycle old factories or commercial buildings—it’s called “adaptive reuse”—are not only using far fewer new materials, but they’re also saving space in landfills, reclaiming old eyesores and saving thousands—and often, tens of thousands of dollars—in the process.

For years, Forbes Industrial Park in Chelsea, MA, was a decaying, underutilized industrial center. Now, this nineteenth century printing plant is being converted into 400 energy-efficient condo units, each a showcase for advanced sustainable urban design. By retaining the concrete structure of the nineteen buildings, the developers saved at least $4 million in construction and materials costs. They also received federal grant money and significant tax breaks to reclaim an old brownfield near an important watershed. 

On a more modest scale, Metro Portland, OR, headquarters building reused the existing concrete frame of an old Sears store as the structure for a new office building. The project included pre-demolition salvage, adaptive reuse, jobsite recycling and the use of recycled-content building materials. The net savings due to lower recycling fees and payments received for salvaged materials totaled $35,000. 

4. Pour Less Concrete

Frost-Protected Shallow Foundations (FPSF) allow footing or foundation depth to be minimized from 48 inches to 16 inches—even in the frozen North—which reduces the amount of concrete needed by two-thirds, with less excavation and smaller impact around the building footprint.
What’s the secret? Insulated footings. They’re wrapped with a rigid expanded or extruded polystyrene foam that provides a thermal barrier from above grade to the bottom of the footing. Any heat that does escape the structure is channeled to warm the earth beneath the foundation, preventing frost heaves. 

Toolbase.org looked at several studies related to FPSF savings and cited a Denver HUD development that saved $3,000 per unit over traditional stem walls and a NAHB Research Center study that demonstrated savings up to $4,750 over slab-on-grade foundations. Another study by the NAHB Research Center in 1988 showed a 15 to 21  percent savings over conventional foundations.

5. Replace Copper with PEX

Picture a power strip for water pipes rather than electrical plugs—that’s a plumbing manifold. It allows multiple pipes to be hooked up to a central cut-off. Simplicity of design makes plumbing manifolds—and the rugged plastic pipes that hook into them—a cost-cutting winner in sustainable plumbing. 

Manifolds are easy to install and eliminate individual cut-off valves for each fixture, so they save on labor costs. But even greater savings may accrue from the use of PEX pipes. PEX (cross-linked polyethylene) is not only much easier and faster to install, but it’s also less environmentally costly to produce. 

An ongoing study by the NAHB Research center indicates that for a 1,500-square foot house with two full bathrooms on the second floor, a kitchen sink, powder room, two hose bibs on the first floor and clothes washer hookups in the basement, PEX costs about $130 more in materials (basically, the cost of the manifold), but saves sixteen hours of installation time.

Because they are flexible, PEX pipes can be installed without 90-degree bends. That means there’s less pressure drop, so a PEX system can be charged with smaller pumps. Sometimes called “home run” systems, plumbing manifolds pipe directly from source to fixtures, thereby reducing standing cold water that must be purged in the line.

PEX has been used to serve European plumbing needs for over thirty years and is rated acceptable for potable water by the National Science Foundation (NSF). PEX is not glued or soldered; it is attached using two crimped brass fittings—one at each end of a run.

Sustainability: Not Just a Pocketbook Issue

These are a few ways that builders can save money by building green. It’s important to note, of course, that the primary objective of green building is not only to save money, but to also promote healthier, high-performance homes that use fewer natural resources in their construction and use. Sometimes that may cost more, but knowing where savings can be garnered helps to balance the overall cost of building green.

Disclaimer: We’re assuming here that you’re working with an experienced crew following best practices. If that’s the case, then yes, Virginia, there actually are sustainable building practices that cost less—if the architecture, engineering and site practices are sound.

Jeff Binder is senior editor of  www.greenbuildingblocks.com, a website devoted to sustainable building techniques.  

References:

1 – Energy Efficiency in Buildings Summary Report, World Business Council on Sustainable Development, August 2007

Item 1: AFT

Item 2: Thursday, October 4 conversation with Mark MacGregor

Item 3: University of Michigan case study

Item 4: FPSF

Item 5: Toolbase

 

 

Construction Business Owner, January 2008