A Longtime Builder Bucks Conventional SIPs in Favor of an Exterior Polyiso Wall System

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After installing 2 million board feet of SIPs (Structural Insulated Panels) this long-time builder has adapted a new strategy for wall enclosures.

A layered polyiso wall system includes wet-sprayed or netted dense-pack cellulose.

The matrix wall layered polyiso system includes wet-sprayed or netted dense-pack cellulose.

While we continue to use SIPs in roof applications, we’ve developed another solution, the matrix wall, that allows easier installation of mechanicals while still achieving an insulation value of R-30 or better.

New Energy Works Timberframers home designer and builder, Jonathan Orpin, finds a layered approach to wall construction yields more benefits when compared to traditional methods or rigid SIPs (Structural Insulated Panels).

“Over 25 years we’ve consumed about 2 million square feet of SIPs. While we continue to use SIPs in roof applications, we’ve developed another solution, the matrix wall, that allows easier installation of mechanicals while still achieving an insulation value up to R-30 or better,” explains Mr. Orpin.

In an effort to increase installation efficiency and minimize time on the job site, while still maintaining critical insulation effectiveness, Mr. Oprin, with his construction and engineering teams, began developing the proprietary matrix wall system. The system is used by New Energy Works Timberframers to enclose homes in a variety of climates, across the nation. Wall panels are open on the interior allowing easy fitting of electric, plumbing, and other mechanicals before cellulose insulation is blown in place.

Timber frames are an ideal construction method for wall systems as they allow the structure to be enveloped fully, with little to no thermal bridging. The walls are designed as a series of panels, as large as can possibly be loaded on a truck, pre-assembled offsite in our shop. Once they arrive at the jobsite they are rapidly installed, typically with help from a crane,” continues Mr. Orpin.

The matrix assembly uses a conventionally framed 2x6 wall with either wet-sprayed or netted dense-pack cellulose on the inside and a polyisocyanurate foam on the exterior. It offers negligible thermal bridging and a managed dew point. Ensuring thermal performance includes a few additional steps: foam sheathing all seams, taping housewrap, flashing windows, and as with all tight homes, consideration to a ventilation system to balance and control internal moisture is also necessary.

See Fine Homebuilding Magazine editorial “A Better Wall with Exterior Foam” by Mr. Orpin in the October/November 2012 edition or contact New Energy Works for more information on this exterior foam wall system.

New Energy Works Timberframers have been designing and building environmentally responsible timber frames across the USA for nearly 30 years from their facilities in New York and Oregon. Offerings include: Timber Framing (design, engineering, manufacturing, build), Enclosure Systems, Fine Woodworking, Recycled and Sustainable wood products. New Energy Works has two LEED AP staff members, is a member of the US Green Building Council and is FSC Certified.

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Jennifer Young
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