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New Book Details I-Joist Construction

A free, downloadable guide explains how to use I-joists (and avoid foam insulation) in high-performance buildings

Posted on Jun 17 2015 by Scott Gibson

A company specializing in materials for high-performance buildings has published the second in its series of ebooks on building techniques, this one focused on the use of I-joists.

475 High Performance Building Supply offers its new book as a free download. The book follows the publication late last year of High-Performance Historic Masonry Retrofits.

High Performance I-Joist Assemblies discusses modified Larsen truss construction for Climate Zones 4 and greater. It offers a short history of the I-joist — invented in 1969 for use in floors and roofs — before going on to explain how they can be used as structural and non-structural elements in the walls of high-performance buildings.

Like its predecessor, this book also makes the argument for foam-free building assemblies. "Foam plastic insulation dominates high performance and green construction today," the introduction says, "a clear victory of the power of chemical company marketing over common sense."

The book says that plastic foam insulation contains toxic ingredients, is a fire hazard, and can lose its thermal insulating properties over time. Instead, the authors make the case for cellulose, fiberglass, and mineral wool insulation.

What's in the book

The book covers four main topic areas, beginning with "ground," the connection of I-joist construction to a number of foundation types. There also are chapters on exterior wall assemblies; penetrations through walls, including windows, doors, pipes and wires; and roofs. Finally, there's a description of the various materials that 475 sells.

In each area, the book includes color-coded drawings with details on interior and exterior air sealing. Both the text and drawings emphasize the importance of controlling air leaks and moisture.

If you'd rather have the book in hardcover form, it can be ordered for $35 with delivery scheduled for August. Readers also can download CAD files of details explained in the book for free.

The book is a beta version, so readers may find a rough spot or two in the text. But 475 says it welcomes feedback and plans to offer additional books in the future.

Since 475 is a retailer of materials used in high-performance buildings, such as sealing tapes and building membranes, readers shouldn't be surprised that the book, a marketing effort by 475, promotes several brand-name products.

475 co-founder Ken Levenson, an architect, is co-president of the North American Passive HouseA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates. Network and president of New York Passive House.

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Jun 18, 2015 7:53 AM ET

oh, c'mon
by Hobbit _

For a "free download", why is 475 trying to run visitors through
the entire cart process and collect needless personal information
instead of just making the PDF available through a straight-up
link?? That's just BS. If someone else wants to run through
their onerous process and then post the real link, that would
help the community better.

I'd expect better from a company like them.


Jun 20, 2015 10:26 AM ET

by Malcolm Taylor

I backed out too

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