Month: May 2024

Generator May Be Missing Heat Shield: Airstream, Inc. is recalling certain 2023-2024 Atlas motorhomes.

NHTSA Campaign Number: 24V314000

Manufacturer Airstream, Inc.

Components EQUIPMENT

Potential Number of Units Affected 8


Airstream, Inc. (Airstream) is recalling certain 2023-2024 Atlas motorhomes. The generator may have been installed without a heat shield, which can expose the subflooring to excessive heat.


Dealers will install the heat shield above the generator, free of charge. Owner notification letters are expected to be mailed July 2, 2024. Owners may contact Airstream customer service at, 1-877-596-6505 or 1-937-596-611 ext. 7401.

Laminated Shingle Repair – May 2024

Can 36-inch laminated asphalt shingles be repaired with metric-sized laminated asphalt shingles?

By Steven R. Smith, P.E., Director of Research & Testing, Forensic Engineer

Laminated shingles today are manufactured in “metric” sizes, which nominally measure one meter in length and about 1/3 meter in width. Long ago, several roofing manufacturers made laminated shingles the same size as their three-tab varieties, which were, and continue to measure 36 inches in length and 12 inches in width. Many of the older, 36-inch-long shingles are still in service today, but can a reliable roof repair be made to an old roof using larger, modern day laminated shingles?

This has become a common question in today’s roofing industry because of possible issues regarding mismatched nailing patterns, misalignments, aesthetic issues, exposed nails and unsightly overlaps.  These questions have further raised concerns that making repairs with larger shingles could cause roof leaks or diminish the wind resistance of the roof.

Haag Research & Testing, a division of Haag Global, delved into this topic by purchasing bundles of discontinued, 36-inch-long shingles and tested repair methods for their viability. We evaluated the process of trimming a larger metric shingle down to size for use in making repairs to the smaller, 36-inch-long shingles. Our procedures evaluated nailing patterns, overlaps, alignments, and even the wind resistance of repairs using our state of the art wind generator. 

Our procedures, technical considerations, test methods, and results are presented in a new technical publication titled “Repairing an Existing 36-inch Laminated Asphalt Shingle with Metric-Sized Laminated Asphalt Shingles”. The paper discusses the technical considerations regarding fastener placement, the use of shingle adhesive, effects of ambient temperatures during roof installation, and even an unexpected consequence when old, but otherwise new shingles (still in their bundle packaging) are installed.  

View Haag Research & Testing’s study, available for purchase here. 
Figure 1: Panel constructed with 36-inch-long shingles to replicate a roof.
Figure 2: Simulating a diagonal row of shingles removed by wind.
Figure 3: Test panel positioned in front of wind generator.
Figure 4: Catastrophic failure of shingles subjected to strong wind. (Note airborne shingles.)
Figure 5: Shingle torn at fasteners during wind testing.



Steven R. Smith is a Forensic Engineer with Haag Engineering Co., and the Director of Research & Testing. Mr. Smith is an experienced forensic engineer who began his career with Haag more than 24 years ago. He spent seven years working as a Senior Lab Technician while earning a Bachelor of Science in Mechanical Engineering degree from The University of Texas at Arlington. He has been involved with the lab throughout his career, and has been able to leverage his extensive and practical engineering field experience with research and testing projects.

Mr. Smith’s areas of expertise include accident reconstruction, mechanical equipment evaluations, code and standards compliance, roofing system evaluations, and fires and explosions. He is a licensed Professional Engineer in Arkansas, Minnesota, Missouri, Oklahoma, Texas, and Wisconsin. He is a member of the American Society of Mechanical Engineers (ASME), Society of Automotive Engineers (SAE), and Pi Tau Sigma National Honor Society. Prior to joining Haag, Mr. Smith was a Petty Officer Second Class in the United States Navy. He trained at the Navy Nuclear Power Training Command Center in Orlando Florida and was stationed on the USS Arkansas (CGN-41), where he maintained reactor and steam plant chemistry, performed radiological controls, and operated mechanical equipment in the propulsion plant.


Any opinions expressed herein are those of the author(s) and do not necessarily reflect those of Haag Technical Services, Haag Engineering Co., Haag Education, or parent company, Haag Global, Inc.

Expert Spotlight: William Ashman, P.E., Forensic Engineer

Haag 100 Year Anniversary - A century of forensic innovation

Engineering Expert Spotlight: William (Bill) Ashman, P.E. - Salt Lake City, Utah

William (Bill) Ashman, P.E., brings a unique blend of passion and expertise to his role as a Forensic Engineer at Haag Global. With a career spanning five years in engineering and consulting, Bill’s journey into this field was sparked by a childhood fascination with architectural sketches and a pivotal physics class in high school. These early influences ignited his interest in engineering, setting him on a path towards becoming a seasoned professional in the field.

When it comes to solving complex engineering problems, Bill subscribes to Kidlin’s Law: “If you write the problem down clearly, then the matter is half solved.” He believes in meticulously documenting the problem at hand, enabling stakeholders to provide feedback and consensus while streamlining the solution process. This pragmatic approach has served him well throughout his career, allowing him to balance budgetary constraints with optimizing effective solutions.

William (Bill) Ashman, PE - Salt Lake City Utah

Effective communication and collaboration are paramount in Bill’s projects, as he understands the importance of timely, transparent communication rooted in reality. By sharing information openly and honestly, Bill facilitates a collaborative environment where problems can be defined clearly, and solutions can be developed efficiently.

One of Bill’s proudest accomplishments in his engineering career was his significant contribution to the design of the Nashville International Airport Arrivals Facility. This project was featured in the Modern Steel Construction October 2022 issue, marking a milestone in his professional journey.

Looking ahead, Bill is eager to expand his range of practice through licensure in adjacent states and aspires to achieve licensure as an “SE” in addition to being a “PE.” His commitment to continuous growth and development reflects his dedication to pushing the boundaries of engineering excellence.

With a solid background in design and forensic engineering, Bill has honed his skills in structural evaluations, wind damage assessment, and moisture intrusion analysis. His expertise extends to bridges, culverts, retaining walls, and sign structures, making him a valuable asset to Haag Global.

Through his meticulous attention to detail, pragmatic problem-solving approach, and unwavering commitment to excellence, Bill Ashman exemplifies the qualities of an exceptional engineer and a notable contributor to our company.

LED Backlight Circuit Board Failure May Cause Fire: Winnebago Industries, Inc. is recalling certain 2021-2023 Sunstar, Vista, 2022-2023 Cambria, Inspire, 2023 Forza, 2024 Minnie Winnie, Spirit, 2024-2025 Porto and Vita motorhomes

NHTSA Campaign Number: 24V295000

Manufacturer Winnebago Industries, Inc.

Components EQUIPMENT

Potential Number of Units Affected 1,166


Winnebago Industries, Inc. (Winnebago) is recalling certain 2021-2023 Sunstar, Vista, 2022-2023 Cambria, Inspire, 2023 Forza, 2024 Minnie Winnie, Spirit, 2024-2025 Porto and Vita motorhomes. The LED backlight circuit board in the cooktop range may fail, causing the board to overheat.


Dealers will replace the cooktop control panel, free of charge. Owner notification letters are expected to be mailed by June 25, 2024. Owners may contact Winnebago customer service at 1-641-585-6939 or 1-800-537-1885. Winnebago’s number for this recall is 184.


Owners may also contact the National Highway Traffic Safety Administration Vehicle Safety Hotline at 1-888-327-4236 (TTY 1-800-424-9153), or go to