APA Blog for Professional Associates - Roofs

I-Joist Construction Details - Performance Rated I-Joists in Floor and Roof Framing

Mon, 08 Feb 2010 08:13:00 -0700

APA has updated the I-Joist Construction Details - Performance Rated I-Joists in Floor and Roof Framing. This installation guide provides updated information on recommended construction details for Performance Rated I-joists in floor and roof applications. The publication also includes recommendations for cantilevers and placement of web holes. The 55-page interactive PDF contains links to exploded views of various construction details.

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Help Desk Question: Nailhead pull-through adjustment factors

Thu, 25 Sep 2008 14:36:00 -0700

Question: What adjustment factor should be applied to the test values published in APA Technical Topic TT-070: Nailhead Pull-Through Strength of Wood Structural Panels?

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Glulam Design Specification & Layup Publications Updated

Thu, 29 May 2008 08:36:00 -0700

APA has updated two publications pertaining to glued laminated timber (glulam) design specifications and layup combinations.

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2008 APA Publications Index Now Available

Thu, 17 Apr 2008 15:15:00 -0700

The APA Publications Index, Form B300 NN, has been updated. The revised 2008 index provides a complete listing of APA design and construction guides, product guides, builder tips, case histories, industrial publications and other materials available from the Association.

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Help Desk Question: What is the difference between four-ply and five-ply panels?

Tue, 18 Mar 2008 14:46:00 -0700

Question: Plans call for five- ply plywood roof sheathing but the lumber yard sent out four-ply. They say they won’t have five-ply in stock until next month. What is the difference between the panels?

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Help Desk Question: How important is 1/32 of an inch?

Fri, 08 Feb 2008 15:27:00 -0700

Question: I specified 1/2-inch roof sheathing for a commercial building. When I was inspecting the project I found that the contractor had installed 15/32-inch. What can be done to correct the situation?

Answer: A wood structural panel that is 15/32 inch thick contains six percent less wood fiber than a 1/2-inch thick panel. The effect on structural properties and characteristics is negligible. In most applications, the 1/32 of an inch difference in thickness of span-rated wood structural panels does not affect performance. In fact, assuring adequate performance in specific applications is at the heart of APA’s rigorous program of quality auditing and testing.

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Help Desk Question: Should I-joists be treated at soffit/eave locations?

Wed, 14 Nov 2007 11:18:00 -0700

Question: What approved methods of weatherization exist for I-joists that are extended for soffit and eave locations on a roof structure? Do you need to have an enclosed soffit and eave, or can they be painted?

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Get the Details on SIPs

Tue, 30 Oct 2007 09:52:00 -0700

New structural insulated panel (SIP) CAD details are now being offered at www.apacad.org. [More]

New Engineered Wood Construction Guide

Mon, 08 Oct 2007 10:05:00 -0700

APA just issued the 2007 Engineered Wood Construction Guide, the major reference manual for using engineered wood products in residential and commercial construction.

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Help Desk Question: Panel Edge Support - What Role Does Tongue-and-Groove Play?

Fri, 31 Aug 2007 13:15:00 -0700

Question: What purpose does tongue-and-groove (T&G) serve on a roof deck or balcony with inhabited space below? What are the advantages of using T&G in an exterior deck application if, for example, the deck is a subfloor to an exterior balcony with waterproofing and 2-inch topping slab over inhabited space, or a low slope roof deck?

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Glulam Beam Design Tables Updated

Tue, 03 Jul 2007 14:52:00 -0700

Glued laminated beams (glulam) are used in a wide range of applications in both commercial and residential construction. [More]

Panelized Roofs Covered in BD+C

Mon, 19 Mar 2007 14:10:00 -0700

Panelized wood roofs have been used in commercial construction on the West Coast for more than 40 years, and are becoming increasingly popular in other parts of the U.S. and Canada. The popular wood roof systems were covered in the February issue of Building Design & Construction (BD+C). Senior Editor and Author Jay Schneider turned to APA for an overview on the all-wood and hybrid systems, and for information on using, specifying and installing panelized roofs. [More]

Overstressed Bowstring Trusses May Not Be Code Compliant

Tue, 13 Mar 2007 09:28:00 -0700

We recently read a very informative article on bowstring trusses that was published in the February issue of Structural Engineers Association of Washington (SEAW) Seattle Chapter Newsletter – "Equilibrium."

The article was written by Paul Gilham, P.E., and Terry McKee, P.E., both from Western Wood Structures. The authors discuss the performance of timber bowstring trusses, which have been used for many years in commercial and industrial applications. A significant issue related to these trusses is that several factors have led to the trusses being overstressed by today’s code requirements. [More]

APA Reveals Wood Deck Test Results in Western Roofing

Wed, 28 Feb 2007 09:24:00 -0700

APA Senior Engineer Fulton Desler authored an article entitled, "Wood Decks: Testing Reveals Best Wood Roof Deck Systems to Resist Wind-Uplift," in the latest issue of Western Roofing magazine.
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Help Desk Question: Exposure Durability of Roof Deck Sheathing

Wed, 24 Jan 2007 13:52:00 -0700

Question: We have specifications for a project that specify Exterior Grade sheathing for a roof deck. The contractor used Exposure 1, and insists that it is the appropriate grade for the application.

Our primary concern is that the contractor did not protect the Exposure 1 sheathing, and it was subjected to heavy rains over a period of five to nine days. It is now protected, but is there a possibility of delamination? Prior to covering, we observed some swelling and minor buckling. Would Exterior Grade sheathing have exhibited the same physical characteristics under these conditions? Could you please shed some light on this subject? [More]