Practical Application of Hygrothermal Modeling of West Coast Wood Deck Systems

Journal Article · Sat Mar 01 00:00:00 EST 2014 · IIBEC Interface

OSTI ID:1150897

Desjarlais, Andre Omer ^[1]; Pierce, Helen Hardy ^[2]; Woodring, William ^[2]; Pallin, Simon ^[1]

---

1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2. GAF Materials Corporation, Parsippany-Troy Hills, NJ (United States)

Roofing systems—particularly in the western part of the United States—are often installed directly to a wood deck, with the building’s insulation below the deck. This construction assembly has a long track record of performance and generally has been used without consequence with traditional built-up roof systems. In recent years, there has been an increase in “conversation” in the roofing industry about anecdotal instances of wood deck deterioration being discovered a relatively short period of time after a roofing system has been installed. Investigations into these occurrences have generally concluded that interior moisture is condensing on the wood deck and causing rot. Hygrothermal modeling of specific roofing systems has confirmed these conclusions. These failures are not being caused by roofing system leaks but by the movement of moisture through the insulation and into the deck and roofing assembly. Unfortunately, these types of failures are becoming more common as the roofing industry (driven by a variety of influences, including regulatory mandate) moves from traditional built-up roofing systems in these markets to reflective membranes—either white or highly reflective “cool”-colored single-ply membranes or white reflective cap sheets. The application of reflective coating can also result in this type of failure....Based on the need for some practical guidelines, a research project was initiated with Oak Ridge National Laboratory’s (ORNL) Building Envelope Group to model the potential for wood deck deterioration under a variety of conditions and to provide guidelines for the amount of insulation that should be installed over a wood deck to reduce this risk.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1150897
• Journal Information: IIBEC Interface, Journal Name: IIBEC Interface Journal Issue: 3 Vol. xxii; ISSN 9999-0034
• Publisher: International Institute of Building Enclosure Consultants
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING