TechPractices: Controlled Environment Structures

TechPractices are outstanding housing projects throughout the U.S. where innovative technologies are implemented. Builders and remodelers can use these examples as models for projects of their own.

Summary

Controlled Environment Structures (CES) is a mid-sized builder operating out of Greenville, Michigan that has used R-Control Structural Insulated Panels (SIPs) produced by AFM Corporation to build approximately 500 homes and additions over the past 11 years. The homes range from 1,000-3,500 square feet and range in price from $75,000-$400,000. CES has also used SIPs to construct several light commercial buildings such as gas stations and small stores. They believe that using these panels results in a house that is more energy efficient as well as stronger.

CES representative Renny Schoonmaker described the company's entrance into the SIPS market: "CES began in April of 1987, recognizing the practical physics that SIPs brought to the building industry. They made their own panels at first, but later took advantage of a local panel manufacturer to supply R-Control panels, which had significant advantages."

Details

CES decided to buy their material from AFM because they viewed the R-Control panels produced by AFM as a superior product. R-Control panels are composed of boron-treated oriented strand board and extruded polystyrene to prevent infestation by termites and carpenter ants. AFM uses an advanced manufacturing process that results in a precision product which includes the use of large radial arm saws for more accurate cutting and application of adhesives with a rotary trowel to provide uniform distribution. A hydraulic press provides three times more pressure than conventional systems when bonding the panels and the core.

AFM Corporation provides a lifetime warranty on structural stability that also covers delamination, a 20-year warranty on thermal stability and a three-year (soon to be five-year) warranty against termite and carpenter ant infestation.

Installation/Construction

CES used to perform all exterior panel installation and rough in, but currently focuses on sales, layout, project management, and training. AFM provides a construction detail book that contains information on how to handle all aspects of installation.

R-Control panels are available in both precut and stock sizes. Precut panels have odd sizes and gable angles cut by the factory. CES cautions against precutting compound miters for complex roof systems because the actual structure in the field usually varies slightly and precut panels typically have to be recut. CES recommends cutting for openings in the field because they have found that openings can be cut in the field for the same or less cost than ordering precut material. This also gives the builder the option to delay the cutting of openings until the windows are actually delivered, thus avoiding any unnecessary weathering and assuring accurately-sized rough openings.

R-Control panels should be blocked up and covered for storage onsite to avoid warping. Once the panels are installed vertically, they will hold up well during construction. Walls should be allowed to dry before the installation of siding materials so that water is not trapped behind them. When framing with R-Control panels it is important to make sure that the panels are not inverted or inside out and both inside and outside skins must be fully supported by the floor or foundation. It is important to understand the entire layout and plan before construction begins-CES stresses the importance of thinking a couple steps ahead until it becomes second nature. Because the panels fit together in a tongue and groove manner, an installation plan must be developed that will avoid awkward installation of the final panels.

At first, CES received quite a bit of skepticism and resistance from the electrical contractors, but after they completed a house or two the electricians realized that it wasn't that difficult to work with at all. After the contractors were experienced with the materials, CES has seen faster installations at less cost.

Benefits/Costs

The use of R-Control panels provides a fast "shell-in." An experienced company such as CES can decrease framing time by up to 50% compared with the time required to frame, insulate, and sheath a stick-framed structure. Beginners can expect to decrease framing time by up to 20%.

CES believes the R-Control panels provide a stronger, more efficient house. They have experienced a drop in problems and callbacks related to warping, nail pops, drywall cracks, and window binding. The strong warranty provided on the R-Control panels has increased customer confidence in the product.

Material costs are higher than conventional framing materials. When taken together, R-Control panels on average cost about 15% more than an equivalent wood framed structure. Mr. Schoonmaker stated that this premium can make it difficult with some buyers in tight cash flow situations, but if the buyer is planning on staying in the home for more than three years, the thermal savings should offset the initial expense.

Code/Regulatory

The R-Control panels have full model code acceptance. AFM Corporation provides in-house design services and documentation to support builders.

CES did say that there are occasional instances in complex structures where additional engineering is required, but are quick to add that this is true of traditional construction as well.

Feedback

CES has been experiencing an increasing interest in their homes. Many of their prospective buyers are now approaching them without the assistance of advertising. Their customers have been exceptionally pleased with their new homes and they frequently ask to be placed on a referral list so that they can tell other potential buyers about their experiences with this building system. When asked about the future of the product, Renny Schoonmaker, of CES, replied "It's a wave that's building at an accelerated rate! Public awareness [of the product] was far better this year than ever before."

Contact(s)

Do you have a specific question? Try the contacts listed below:

AFM Corporation - R-Control
24000 Highway 7, suite 201
Minneapolis, MN 55331
1-877-R-CONTROL
www.r-control.com

Controlled Environment Structures
Greenville, MI
800-968-1818

Structural Insulated Panel Association (SIPA)
P.O. Box 1699
Gig Harbor, WA 98335
253-858-7472
www.sips.org