Commercial contractors face numerous competing priorities, including managing tighter budgets and building greener while maintaining high quality and utilizing advanced building techniques.
One solution—structural insulated panels (SIPs)—offers advantages over other light commercial construction such as stick-built framing, concrete masonry units and tilt-up concrete, including faster close-in times, high strength and several sustainable attributes.
Building with SIPs
SIPs are pre-manufactured wall, roof or floor components delivered to a jobsite ready to install in sections up to 8 feet by 24 feet long. They typically are made with oriented strand board (OSB) that is laminated and pressure-cured to a rigid insulating foam core.
Common applications include single-family and multifamily homes, schools, churches, offices, retail and other light commercial buildings.
The design and construction process with SIPs is straightforward. The architect provides the construction documents to a SIP manufacturer or dealer, which converts them into shop drawings that show each panel’s specific dimensions. After review by all parties, the manufacturer or dealer finalizes the shop drawings, makes the panels and delivers them to a jobsite pre-numbered to coordinate with installation plans.
Fast Close-in Times
A key advantage SIPs provide in today’s tight economy is the ability to dramatically reduce dry-in time. The large, single-piece panels enable contractors to install entire wall, roof and floor sections at one time. They eliminate the need for separate framing, insulating and sheathing work onsite, and enable subcontractors to start and finish work faster because walls, roofs and floors are plumb and square.
In addition, manufacturers pre-cut window and door openings, including curves, arches and complex shapes. Depending on an opening’s dimensions, subcontractors do not need to spend time installing separate headers. The panels also come with pre-cut electrical chases, eliminating the need to drill through studs for wiring.
In a new elementary school built with SIPs, the Clark County School District in Las Vegas reduced close-in time by nearly 80 percent—from a typical 118 to 220 days to only 45 days. “The general contractor was shocked at how fast the panels installed,” says Gary Radzat, president of Shell Building Systems, Sebastopol, Calif., the SIP design and installation consultant for the Jacob E. Manch Elementary School. “He said he’d never seen that much of a schedule reduction.”
Using SIPs saved the district approximately $1 million in direct construction costs.
Strength and Consistency
SIPs are strong and in most applications are structurally self-sufficient. Designers can use them in wall, roof and floor systems in place of other structural elements.
While frequently used in one- or two-story buildings, SIPs have been successful for taller structures. Last year, Western Wyoming Community College, Rock Springs, Wyo., opened a 28,000-square-foot housing complex with 48 bedrooms spread throughout four stories—the tallest self-supporting SIP structure built to date.
In walls, SIPs can bear high loads and offer great strength in racking diaphragm shear capacities. These capabilities enable the panels to be used in typical exterior walls, as well as shear walls to resist earthquakes and high winds. Extensive testing on SIPs has proven their use in high-risk earthquake areas, including seismic zones D, E and F.
In roofs, SIPs can be used without an engineered truss system and can span long distances—up to 20 feet based on design parameters. As a result, they can help create open interior spaces by reducing the need for intermediate structural supports.
Designers also can incorporate SIPs into floors, typically over crawl spaces that require an insulated floor system.
Green Building Benefits
Designers and contractors increasingly specify SIPs to help meet green building goals. Notably, SIPs lower energy costs and reduce construction waste by up to 60 percent, as well as improve indoor air quality and support recycling.
SIPs provide exceptional energy efficiency compared to other construction methods because they combine insulation and structural elements in one unit. By contrast, with stick frame or concrete construction, insulation is added after the structure is built. It is difficult to apply fiberglass batts or blown-in insulation without leaving gaps, especially in corners and other hard-to-reach places. Also, because SIPs come in large sections, fewer gaps need to be filled, resulting in a tighter building envelope.
When evaluating the R-values of whole wall assemblies, the U.S. Department of Energy’s Oak Ridge National Laboratory found SIPs offer higher thermal resistance than framed systems.
The improved insulation reduces ongoing energy use and costs, and helps reduce HVAC system requirements. On the Las Vegas Manch School project, consultants estimate SIPs cut the HVAC equipment capacity in half.
In addition, energy-efficient building materials such as SIPs may qualify commercial building owners for a tax deduction up to a $1.80 per square foot.
The lower operating costs of a SIP building can be a key market differentiator, helping developers sell or lease commercial space easier.
Plus, stick-built construction generates large scrap volumes from cutting stock size studs and joists to length. Because SIPs are manufactured in a controlled setting, more careful material management is possible than on a jobsite, reducing waste disposal fees.
Many SIPs are 100 percent recyclable, as well as have foam cores made from a specified level of recycled content. The OSB skins come from fast-growing, renewable trees and are manufactured using a high percentage of each log for efficient resource use.
Because SIPs provide a tight building envelope, they help reduce infiltration of common pollutants such as radon, molds, pollen, volatile organic compounds (VOCs), lead dust and asbestos. Manufacturers typically produce SIPs without the use of chlorofluorocarbons, hydrochlorofluorocarbons or formaldehyde, and zero-VOC mastics are available. In conjunction with other low-emitting building materials, SIPs can help support healthy indoor air, which the U.S. Environmental Protection Agency reports is linked to improved employee and student performance and attendance.
Given the multiple environmental advantages, building professionals can use SIPs to earn up to 23 points under the U.S. Green Building Council’s LEED for New Construction rating system. Depending on the project and overall design, applicable point categories are energy and atmosphere, materials and resources, and indoor environmental quality.
Planning, designing and constructing commercial buildings is more challenging than ever. Thriving in a down market requires new ways of thinking. SIPs are a tried and trusted construction solution to improving light commercial construction.