Cost-efficient wood framing leads to energy efficient schools

Bethel School District is proving they can save construction costs and build energy-efficient schools at the same time, leaving more money for educating students.The District reports an 81 percent ENERGY STAR rating overall; several of their 17 elementary and six middle schools have ratings ranging from 95 to 98 percent. And, while size, configuration and age of the 23 facilities vary, one thing remains constant: each is wood-frame.

Project Details

  • Date Completed

    2006 - 2012

  • Location

    5 Different School Examples

Energy Efficiency Funds Better Education

Cost efficiency is a key goal for Bethel School District Superintendent Tom Seigel, a former Navy commander. He challenges his operations team to run facilities as efficiently as possible, so they can put the savings in the classroom. “Half of our schools are new or completely modernized,” said Seigel. “Our buildings are recognized as being energy efficient with excellent technology to support student learning. Exceptional staff, design innovation, accountability and conservation efforts have kept our construction and operations costs down.”

Like school districts across America, BSD has a limited amount of money to spend on facilities. “If I can save money by using wood framing in our new building projects, I can then use that money to buy more expensive but more efficient mechanical or lighting systems,” said James Hansen, BSD’s Director of Construction and Planning. “And that, in the long term, helps us save money in the general fund. Our decision to improve energy efficiency in our schools wasn’t driven by a commitment to the environment, although that’s an added benefit. It was a very practical decision. We want to save money on the operation side so we can have more money for education.”

Wood Costs Less and Reduces Construction Time

Bethel School District reports construction costs per square foot that are much lower than the average for other schools in the region. Hansen is quick to credit the fact that they consistently use wood framing, which saves them both in cost of materials and erection time.

“In Western Washington, wood studs cost almost half as much as metal,” he said. “In 2012, our costs averaged $0.53 per lineal foot for wood versus $0.98 for metal studs. Plus, on a two-year project, I probably cut three to four months off construction time because wood framing goes up so much quicker.”

Babbit Neuman Construction Company builds both wood-frame and metal schools throughout the Pacific Northwest; they have built several of BSD’s schools. “Scott Babbit told me we save about 20 percent in materials and installation by using wood framing for a school,” said Hansen. “So, if it’s a $10 million project, this can be a $2 million savings, which is significant.”

Wood Framing Improves Envelope Efficiency

BSD’s construction philosophy is to reduce costs for framing, which allows them to invest in (among other things) better, more efficient lighting and HVAC systems. They also maximize their use of inexpensive batt insulation, which helps improve energy efficiency over time. “Why put just six inches of insulation into a 12-inch cavity?” asked Wayne Lerch, principal with Erickson McGovern Architects, a Tacoma, Washington-based firm that has designed a number of BSD facilities. “Batt insulation is a cost-effective way to increase energy efficiency just by filling the spaces, and we take advantage of that with wood framing.”

Wood studs do not transfer heat and cold in the same way metal studs do, so wood also helps improve the energy efficiency of the exterior envelope. “You can seal a wood-frame building tighter than you can a metal or a concrete building,” said Hansen. “Plus, because woodframe walls, floors and roofs easily accommodate batt insulation, it’s simple and cost effective to over-insulate.”

For example, Hansen said they typically use 12- to 14-inch-wide laminated strand lumber (LSL) studs in gymnasium walls. “We fill those cavities up to get an R-38 or an R-40 rating, whereas code requires only R-21,” he said. “A lot of districts use concrete in the gym because they think they need it for durability, but concrete is hard to insulate. We can easily control temperature because we super insulate that space. And durability is no problem because we use medium density fiberboard (MDF) to protect the walls.”

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