Category: Articles

The Brittleness Test- June 2018

THE BRITTLENESS TEST

In this post we talk about “The Brittleness Test.” However, before delving into the specific discussion of “The Brittleness Test,” it is important to first understand how industry-accepted test methods are developed so we can ask – Is “The Brittleness Test” an industry-accepted test method?

Industry-Accepted Test Methods

Consensus Test Methods:

Testing organizations frequently develop and issue testing procedures for building materials. Typically, the way such procedures are conceived is through a technical committee within the organization. These technical committees are open to the public, comprised of stakeholders in the industry, and are typically volunteers. For the example of roofing materials, representatives from manufacturing, insurance, those who represent property owners, contractors, engineers, scientists from research facilities, and representatives from trade organizations, among others, could make up the members of the committee. The committee then assigns different sections of the standard as well as research, to be written or undertaken by the different members. The draft standard is then iteratively submitted to the rest of the committee for comments, edits, and suggestions, until a final version is prepared and balloted. Organizations such as ASTM and ANSI generally publish testing procedures in this fashion. More information on ASTM and ANSI test standard development can be found at the following links, respectively:

https://www.astm.org/MEMBERSHIP/standardsdevelop.html

https://share.ansi.org/Shared%20Documents/Standards%20Activities/American%20National%20Standards/Procedures%2C%20Guides%2C%20and%20Forms/ANSI-Essential-Requirements-2018.pdf

Peer-Reviewed Methodologies:

Another way to publish scientific methodology is through an academic journal. This is typically referred to as a peer-reviewed publication. The peer-review process begins with scientists observing, studying, and qualifying or quantifying the phenomenon. These scientists then complete their analysis and write an article on their results. The article is submitted to the editor of a relevant journal. In the case of building science, articles can be submitted to the journals of Building and Environment, Construction and Building Materials, Materials and Structures, Building Research and Information, or Materials in Civil Engineering, among many, many others. The editor of the journal would then send the article to other well-known scientists, in the same field, for their review. These peer reviewers read the article and provide feedback to the editor. At this stage, the editor can compile a list of comments for the authors or if the article doesn’t meet the scientific standards of the journal, it can be rejected. If the article is not rejected, the authors then answer reviewer’s questions and comments, revise the document, and resubmit for further review. The process iterates until the peer reviewers and editor are satisfied the scientific standards of the journal are met and the article is published in that journal.

These two ways in which testing methods or procedures are published are important because it shows that procedures have been reviewed by an established and rigorous process by stakeholders in the industry—the same entities that will use the procedures. Further, these processes assure the reduction of bias by any one branch of the industry because it was compiled by members of the different branches of the industry or it was reviewed by different members of the industry. In effect, it serves as a checks and balances system.

So, what is “The Brittleness Test”?

Many in the industry refer to “The Brittleness Test” as a method by which the reparability of an asphalt composition shingle roof can be assessed; however, is “The Brittleness Test” that you’ve encountered an industry-accepted test method, as outlined above?

The answer is likely, no. There is a widespread misconception that there is a prescribed methodology to “The Brittleness Test”. There is no ASTM, ANSI, Haag, or other industry-accepted, peer-reviewed method to determine or quantify shingle brittleness. But why is this important?

Let’s examine what some inspectors refer to as “The Brittleness Test.”

Lifting the shingle X-inches

Some inspectors refer to “The Brittleness Test” as un-bonding a field shingle and lifting the end of the shingle until it is X-inches above the roof surface. However, the lifting force is not specified and rarely is the lifting dimension justified. It is clear that without limiting the lifting force or justifying the significance of the lifting dimension, such a method can be misused.

We often come across inspectors that will specify the lift dimension as a dimension equal or greater to 6 inches. In looking at a proper shingle installation, typical nail locations for a three-tab shingle are 5-5/8 inches and for some laminated shingles can be less than 6 inches. Specifying a lift dimension of 6 inches or greater, can result in tearing of the shingle around the fasteners, without having anything to do with the age/condition of the shingle. Figure 1 below shows an example of lifting a tab straight up without causing damage. Its end measured less than 5 inches above the roof.


Figure 1 – Lifting a shingle tab without causing damage measured less than 5 inches.

Bending the shingle to X-degrees

Some inspectors refer to “The Brittleness Test” as un-bonding a field shingle and bending it to a certain angle. However, the lifting force is not specified and rarely is the lift angle justified. Further, rarely is care given to the radius of curvature of the shingle. For example, inspectors often refer to 90 degrees as is shown in Figure 2 below:


Figure 2 – An illustration of “The Brittleness Test” where a shingle corner is bend upward to a 90-degree bend. Note the difference in the two radii of curvature.

It is clear how a tight radius of curvature, as is shown on the left, is more likely to damage the material (this could happen when bending the shingle against the overlying shingle or against its fasteners), regardless of its age/condition when compared to the example on the right (without the shingle binding on the overlying shingle or its fasteners). Figure 3 is an example of a 90-degree bend, with a tight radius of curvature, causing damage to a new three-tab composition shingle.


Figure 3 – “The Brittleness Test” 90-degree bend causing damage to a brand new, unweathered shingle.

It is also clear that a 90-degree bend is not necessary to access the shingle’s fasteners.

Pinching the shingle corner:

More recently, we have encountered inspectors who claim that “The Brittleness Test” is the pinching of the shingle corner. In effect, the test they employ is bending a shingle corner against itself (180 degrees) and pressing down on the crease as is shown in the diagram below:


Figure 4 – An illustration of “The Brittleness Test” where a shingle corner is pinched.

It is clear that such a test could cause damage to any shingle regardless of its age/condition. Such a bend is not necessary in conducting an individual shingle replacement. As such, it is unclear how such a test is related to reparability. Below is an example of this test causing damage to a new three-tab composition shingle.


Figure 5 – “The Brittleness Test” corner pinch causing damage to a brand new, unweathered shingle.

These are the most common “Brittleness Tests” other inspectors have reported or shown to us; however, the list of other “Brittleness Tests” with different failure criteria goes on and on. This conversation could further be expanded when considering the effect temperature has on the shingles. However, being that there is no industry-accepted, peer-reviewed, step-by-step, quality-controlled methodology, we cannot assure that performing “The Brittleness Test” can be accomplished in a repeatable scientific way. It is clear that the lack of specificity, procedure, consistency, and repeatability in these methods can lead to biased results.

If there is no “Brittleness Test,” how do you determine reparability?

Assessing the reparability of a shingle involves determining whether the fasteners can be accessed without causing damage to the overlying shingle; however, can this be accomplished without an industry-accepted test method?

Legitimate concerns regarding reparability can be addressed by attempting to remove and replace a shingle. First and foremost, permission of the property owner should be obtained. Then, the target shingle and the shingle directly upslope can be carefully unbonded, the fasteners for the target shingle and the shingle directly upslope can be removed, and the target shingle removed. The adjacent shingles (not the removed shingle) can then be closely inspected for damage.

In using this method, however, be cautious of purposeful efforts by others to damage the roofing. Figure 6 is of an instance where one of our engineers encountered another inspector that attempted to demonstrate the shingle’s “brittleness”. The inspector attempted to demonstrate removing a shingle while lifting his pry-bar straight up to pry out a nail, clearly causing damage.


Figure 6 – An example of purposeful efforts by others to damage the roofing.

Another method to determine the reparability of a shingle could be to carefully un-bond a shingle or find an intact non-bonded shingle, then carefully lifting the shingle enough to expose the fasteners and release the shingle. Upon release, the lifted shingle can be inspected for damage. Any shingles that were unbonded for examination should also be resealed with quarter-sized dollops of roofing cement. Figure 7 illustrates this procedure in a case where shingles lay flush on the roof without having incurred any damage.


Figure 7 – Documentation of a shingle before lifting, lifting enough to expose fasteners, and release, and after releasing the shingles showing they sat flush without having incurred any damage.

It is clear that for either of the two presented methods to determine reparability, discretion and good judgement are necessary. Both are not only necessary in determining reparability, but if the shingles are determined to be repairable, accounting for the difficulty of the repairs.

 

 Carlos Lopez, Ph.D., P.E., Haag Engineer

Carlos graduated from the UN of FL with a BS, MS, and Ph.D. in Civil Engineering.  He is a member of the American Association for Wind Engineering, the American Society of Civil Engineering, and the American Concrete Institute.  Carlos has assessed damage to hundreds of roofs since joining Haag in 2012.  He also served as a key developer of the Haag Certified Inspector-Wind Damage Course.  His primary areas of consulting are structural evaluations and general damage assessment.  He also works in the Haag Research/Testing laboratory, designing new test apparatuses and performing experiments and industry-accepted testing procedures. 

Any opinions expressed herein are those of the author(s) and do not necessarily reflect those of Haag Global, Inc., Haag Canada, or any Haag companies. 

February 2018 Blog Post

 

Identifying HAIL-CAUSED FRACTURES IN THERMOPLASTIC ROOFING

In most roof systems, hail-caused damage is readily identifiable, but in other systems, such as single-ply thermoplastic roofing, the damage initially can be less apparent. Imagine this scenario: a severe thunderstorm deposits hail at a commercial property. There is immediate concern that the single-ply roofing membrane had been damaged by hail.  An inspection of the roof reveals spatter marks (areas of grime and oxide cleaned from surfaces struck by hailstones) and dents in metals confirming that hail had fallen at the property.  The membrane is examined and the plastic single-ply is determined as not damaged.  A few months later, several leaks are discovered after a heavy rain storm, prompting a follow-up roof inspection.  Hail-caused fractures are discovered throughout the membrane during the second inspection. What likely happened?

Depending on the type of roof system, hail-caused damage takes different forms. Hail-caused fractures in thermoplastic roofing range from circular to semi-circular to multiple fractures in circular patterns.  Frequently, the fractures are especially “tight” after hailstone impacts. Over time, the membrane “relaxes” due to the effects of weathering, and the fractures accumulate grime making the fractures more apparent.  The impact-caused fractures may not be visible to the naked eye immediately after they originate, but proper inspection techniques will aid us in identifying hail-caused damage on our first inspection visit.

First, we need to know where the thermoplastic membrane is most likely to be damaged by hail. The membrane is most sensitive to impact damage at the edges of underlying steel stress plates (washers). Depending on the roofing application, these may be found within lap seams and atop the insulation immediately below the membrane. The next areas most sensitive to damage are those not solidly supported:  commonly base flashing at parapet walls and curbs. Lastly, consider membrane in the field of the roof, especially where underlying insulation boards have wide gaps or are uneven. Importantly, thermoplastic membranes become more brittle with age and therefore more impact sensitive. Sometimes brittle sections correspond to roofing areas that regularly pond water, as this prolonged contact accelerates the aging process.

Second, we will identify locations where the membrane had been struck by hail. Normally, a thin layer of grime has accumulated on the roof.  Hailstones that impact the roof clean away this surface grime, leaving a spatter mark.  In general, larger or softer hail creates larger spatter marks than smaller or harder hail.  Note that thermoplastic roofing typically is installed over rigid foam insulation.  Impacts by large hail can dent the insulation.  For this reason, even when spatter marks are not visible, we can locate impact sites by feeling dents in the insulation.

Now that we know where to look and what to look for, we can examine the roof for hail-caused fractures.  Once an impact location is found (whether indicated by a spatter mark, a dent, or both), we can examine the membrane for a fracture.  If a fracture is not visible, rub the impact with your fingers to force grime into the fracture (if one exists).  Larger areas measuring a few square feet can similarly be rubbed by hand, providing larger areas to examine.  If no fractures are observed within a test area, one could consider rubbing the entire test area by hand, providing an additional opportunity to locate hail-caused fractures.

 

                                                                                        

There also are instances where an inspection might reveal hail-caused fractures from a storm that occurred long ago. Old fractures have been exposed to the weather longer than more recent fractures, and hence, they tend to exhibit the following characteristics:  their edges are generally more round, they are darker in color, and they are generally wider.  In some cases, readily visible hail-caused fractures are observed on the roof, yet none align with spatter marks, which would clearly indicate that the fractures were not the result of the recent hailstorm.

The use of these techniques will aid an inspector in determining if a thermoplastic roofing membrane had been damaged by hail and whether the damage had occurred recently or if the damage was created long ago.  Understanding where to look, what to look for, and how to detect hail-caused damage to thermoplastic roofing is critical in making a proper analysis.

Steve R. Smith, P.E. and Haag Senior Engineer
Steve Smith completed nuclear power training with the United States Navy in 1994. He was honorably discharged in 1998 and went to work for Haag Engineering Co. as Senior Laboratory Technician. Steve has performed hundreds of hail impact tests on a variety of products including roofing, siding, and automobiles.  He graduated from the University of Texas at Arlington in 2005 with a Bachelor’s degree in Mechanical Engineering and is a member of the American Society of Mechanical Engineers, the Society of Automotive Engineers, and the National Association of Fire Investigators. Steve has inspected and assessed damage to a number of roof systems, including single-ply systems, composition shingles, cedar shake and shingles, concrete tiles, slates, and built-up roofing.  See his full profile here.

January 2018 Blog Post

UPDATED HCI-RESIDENTIAL ROOFS COURSE

 

In January 2018, an updated version of the HCI Residential Roofs course will launch. This has been the most popular of the HCI courses, with over 10,000 attendees since the program’s launch, and we seek to provide an even better experience for the next generation of students. The goal of the update was to make the course more engaging for the attendees and provide more direct learning experiences. The course will provide current building code information and have information on newer roofing products that will help the attendees in their day-to-day work tasks and also earn the Haag certification that will set them apart professionally.

The HCI Residential Roofs course covers the various types of steep-sloped roof systems found on residences and multi-family buildings, as well as information on the severe weather events (hail and wind) that can damage roofs. In addition to asphalt shingles, the materials covered included wood shakes and shingles; clay, concrete, fiber-cement, and synthetic tiles; slate shingles; and metal roofing. For the various roof systems, video segments will show manufacturing methods, installation techniques, and repair procedures. Case studies will be presented to show how Haag engineers have made forensics evaluations on particular projects to determine whether observed damages were caused by construction defects, manufacturing issues, mechanical contact, hail impact, or wind. Videos also will be shown of simulated hail impacts and the wind simulator machine in the laboratory of Haag Research & Testing. In learning groups, attendees will perform roof repair versus replacement cost calculations. The course will also show and discuss the growing role of UAV’s, a.k.a. “drones”, in making roof inspections.

The HCI Residential Roofs course is designed with several objectives in mind for our attendees. Upon completion of the course, the attendees will be able to identify the various components and materials used in typical residential (steep-sloped) roof systems. For particular steep-sloped roof systems, the attendees will be able to identify the type of roofing; identify conditions related to manufacture, installation, normal weathering, hail impact, wind forces, and mechanical contact; and the explain repair options and methodologies. Once damage has been identified to a roof system, attendees will learn techniques to estimate repair costs and compare the cost of repair to roof system replacement. Finally, the attendees will be learn methodologies to report the findings of their roof inspections.

If you have taken HCI Residential Roofs previously and are approaching your renewal time, this is a great opportunity to attend the updated course. Or, share this information with your co-workers and colleagues. An upcoming schedule of courses can be seen here.

Richard F. Herzog P.E., Meteorologist, RRC, and Haag Principal Engineer (04/2015)

Richard Herzog’s primary areas of consulting are Roofing Systems, Building Envelope Systems, Evaluation of Wind Damage to Structures, Construction Defect Evaluations, Meteorological Investigations, Development of Hail Analysis Software, and Alternative Dispute Resolution.  He serves as a primary advisor in the creation of many Haag Education seminars and products.  See his profile here.

Wind Codes Revisited – November 2017 Blog Post

Wind Codes Revisited

 

Every year in the United States, tornadoes and other high wind events cause damage to wood-frame residential construction.  When these events occur, we are bombarded with images of extensively damaged buildings and home-owners sorting through debris trying to salvage their belongings.  Inevitably, these communities rally together afterwards to support those impacted and promise to rebuild.

When I was growing up, I would watch these news stories absolutely fascinated.  I couldn’t imagine how wind could cause such extensive damage.  I also didn’t understand why people would rebuild in the exact same way as they did before.  It seemed logical to me that if your house was destroyed by a tornado, wouldn’t you want to build a stronger house so it wouldn’t happen next time?  Was it even possible to build stronger houses, or did we have to accept this level of destruction?

These questions directed my research over the past several years and I tried to better understand wind loading, specifically in tornadoes.  Tornadoes are not as well understood as other straight-line winds, such as hurricanes or thunderstorms.  This is due to the fact that it’s difficult to obtain direct wind measurements in a tornado.  Fortunately, technological advances, in the form of mobile Doppler radar and tornado simulators, have allowed for a better understanding of the tornado wind field.

By understanding the characteristics of damaging wind, be it from a hurricane or tornado, engineers are able to estimate the wind loads on buildings.  Knowledge of the magnitude and direction of the wind loading provides engineers the tools to develop techniques to better resist these loads and mitigate damage.  These methods have been successfully employed in the state of Florida, which adopted some of the strictest wind provisions in the United States after Hurricane Andrew.  Strengthened construction techniques, for example, include the use of ring shank nails and straps at the roof-to-wall and wall-to-foundation connections.  Evidence of improved structural performance was seen during the 2004 hurricane season, and most recently with Hurricane Irma, when houses built after the adoption of the Florida Residential Code performed better than those built earlier.

While Florida has successfully utilized stricter wind provisions, adoption of similar techniques has not been commonplace in the interior portion of the United States, especially locations subjected to tornadoes.  It would be beneficial for tornado-prone areas to employ similar techniques to those in used in Florida, especially since the majority of tornado damage is rated EF2 or lower on the Enhanced Fujita scale, implying strengthened construction could mitigate the most common damage modes observed.  These techniques can be employed in a cost-effective manner and greatly improve a building’s resistance to high winds, as shown in both statistical models and full-scale laboratory applications (see Fig 1).  So next time a community is impacted by any type of high wind event, it is my hope that they not only rebuild, but they rebuild stronger.

You can learn more about wind science and wind damage assessment to structures in our HCI-Wind course! To learn more, visit our HCI website.

Figure 1:  Full-scale high wind testing of standard (left) and strengthened (right) construction.

 

Christine Alfano Ph.D., P.E., Forensic Engineer

Christine Alfano joined the Haag staff in 2017. She is a meteorologist and engineer who serves Haag clients in the greater Charlotte, NC area. Christine has taught Technical Writing and Mechanics of Materials as a visiting professor at Valparaiso University’s Department of Mechanical Engineering. Christine has also worked with NWS damage assessment teams following the Birmingham tornado, and with NASA to develop methods to estimate oceanic heat levels. Christine earned a Bachelor of Science in Meteorology, Summa Cum Laude, from Valparaiso University. She earned a Master of Science in Meteorology at the University of Miami and a Doctorate in Civil Engineering from Colorado State University. Christine’s work has been published in the Journal of Structural Engineering and the Journal of the Performance of Constructed Facilities. Christine is a member of the American Meteorological Society, Society of Women Engineers, American Society of Civil Engineers, and the National Fire Protection Association. Christine’s honors include Chi Epsilon Pi Meteorology Honor Society, American Meteorological Society Undergraduate Scholarship recipient, American Meteorological Society Undergrad Fellow, University of Alabama Graduate Council Fellowship, Colorado State University Dr. Jack E. Cermack Wind Engineering Scholarship recipient, and Federal Alliance for Safe Homes International Code Council Scholarship recipient.

Click here to view Christine’s profile. 

July 2017 Blog Post

Haag Helps Repair Military Base in Iraq

In early 2017, Dan Behrens, P.E., Haag Senior Engineer, (Minneapolis) traveled to Iraq and spent time living and working on an active military base while he worked to inspect an airplane hangar for damage at a US military base. In Dan’s own words, here is a brief summary of Dan’s trip and inspection in an active war zone:

I was initially asked to inspect a large hangar for some roofing and siding issues, possibly attributed to either wind, construction, foundation movement, or blast effects. It became obvious upon arrival that the issues included the main structural frame and secondary structural members, and that the primary cause of damage wasn’t wind-related.

The hangar in question was built on an Iraqi air force base for our (one time) friend and ally, Mr. Saddam Hussein, in the 1970s or ‘80s. In July 2003 however, Google Earth imagery shows two large holes in the roof, when the United States military was in the process of invading Iraq to depose our enemy, Mr. Saddam Hussein (times had changed). I noted that the repairs were of varying vintage, so it’s possible the hangar was damaged during the first Gulf War in 1991 as well.

Being an active war zone, my accommodations consisted of a private containerized housing unit with a bathroom with running water. I ate my meals at the same dining hall as the soldiers, airmen, and marines. It is protocol on base that service members carry weapons at all times. It was a bit unsettling to grab for the last cookie versus someone with an M4. (I let them win.) I lobbied for a weapon to carry just in case, but they said no. I was left with nothing but my steely gaze and razor wit for defense. Luckily, neither were needed.

All in all, the trip was a great experience; it was striking how young most of the service members were. To paraphrase Burke, it was humbling to see kids standing ready in the night to visit violence upon those who would harm us.

I have to say a big thanks to the team at Haag who supported me during this trip.

My thanks go out to the team who stayed home; this wouldn’t have been possible without their help. Most especially my wife, Kim, who stayed home with our three-month-old twins – I was happy to find that my house key still worked when I got home. In addition, Tami Fugle, John Ortenblad, Richard Herzog, and Rob Danielson in MN and Jeremy VanLeeuwen in KC all covered inspections for me or otherwise cleaned up my messes. Thanks also to Patrick and Rob at Haag Technical Services for their help on drafting for the final report.

I’ve attached a few photos. The military was very much down on photographing anything operational, so no pics of the vehicles, drones, or artillery batteries.

 

 

The image below shows the hangar siding condition, with the American side in the background.

Daniel B. Behrens, P.E.

D Behrens

Daniel Behrens graudated from the University of Minnesota with a Bachelor of Civil Engineering. He is a Senior Engineer at Haag Engineering Co. in Burnsville, Minnesota, and is licensed as a Professional Civil Engineer in 13 states. Mr. Behrens is currently a member of the American Society of Civil Engineers and the American Institute of Steel Construction. Mr. Behrens has been with Haag Engineering since 2009, and has inspected and assessed damage to hundreds of roof structures. His primary areas of consulting are structural evaluations, roofing systems, general civil engineering evaluations, moisture source evaluations, and building envelope evaluations. Mr. Behrens helps develop and present continuing education seminars as an instructor at Haag.

June 2017 Blog Post

SETTING THE STANDARD FOR DAMAGE ASSESSMENT TRAINING:
HCI’S FIRST DECADE

Haag Engineering has been offering property damage training with an engineering/scientific perspective, for nearly a quarter of a century.  In 2005, after many requests and suggestions that Haag offer some sort of industry certification, development of the Haag Certified Roof Inspector (HCRI) program, a first of its kind damage assessment certification, began.

In June 2007, Haag proudly rolled out the HCRI-Residential roof program, which very quickly caught the interest of insurance carriers, roofing contractors, engineers and roofing consultants.  The initial feedback about the class exceeded our expectations, and we quickly determined that a second certification on flat roof systems would be up for development next.  In 2009, HCRI-Commercial was rolled out.  Over half of the first few classes of HCRI-C were made up of students who had successfully completed the HCRI-R class.

2012 brought a few changes to the HCRI program. Development began on our first damage assessment certification focusing on all property (not just roof) damage associated with the peril of wind.  We also re-branded the program from HCRI to HCI (Haag Certified Inspector).

Over the course of the last 10 years, over 14,000 people have come through Haag’s three certification programs, and HCI has set the standard for roof and wind damage assessment in the industry.  Haag Certified Inspectors have benefited from their certification with increased knowledge, increased inspection efficiency and confidence and increased credibility amongst their peers. Not to mention the “value adds” that come along with being Haag Certified!

HCI’s get to take advantage of special discounts from product and service providers that service our industry, for example HCIs get automatic “gold” pricing from EagleView on their roof measurements, along with discounts from other companies that service our industry, just for being Haag certified! Another benefit is access to Haag’s wealth of damage assessment expertise through our “Ask an Engineer” program, exclusively for active Haag Certified Inspectors.

Haag Certified Inspectors can look forward to some exciting news coming up this summer and in the next few months.  Additional certification opportunities, special discounts exclusively for HCIs and more.

If you’re not yet Haag Certified, take advantage of our great summer pricing (for classes taking place June-August).  Current HCIs, be looking for our 10th anniversary newsletter coming out in early July with lots of great features and some exciting news!

The staff of Haag Education wishes you all a safe and memorable summer!

 

Ryan Holdhusen
Vice President- Education

 

 

 

May 2017 Blog Post

TWIRL– Tornadic Winds: In-situ and Radar measurements at Low levels

Haag engineer Tim Marshall will be part of the TWIRL PROJECT from MAY 7-JUNE 15. TWIRL stands for “Tornadic Winds: In-situ and Radar measurements at Low levels”.  TWIRL’s mission is to deploy instrumented pods in the paths of tornadoes so they can use these data to correlate wind speeds with the Doppler on Wheels (DOW) radar observations. Tim will be working for the Center for Severe Weather Research (CSWR), which is a non-profit science group, funded by the National Science Foundation.

 

“TWIRL researchers are focusing on low-level winds flowing into the cores of tornadoes,” said Ed Bensman, program director in NSF’s Division of Atmospheric and Geospace Sciences, which funds TWIRL. “They’re using a combination of surface weather sensors placed ahead of developing storms, and Doppler-on-Wheels [DOW] mobile weather radars. From TWIRL, we will gain a better understanding of the role low-level winds play in the development of tornadoes, and why some tornadoes become the most violent.” See more information about TWIRL here.

Tim is honored to be selected for this 5th deployment with the TWIRL team, and the only private person involved in this project.  All other TWIRL members are scientists affiliated with CSWR, universities, or graduate students in atmospheric science.

Tim’s interest in tornadoes, which led to his career as a forensic engineer and meteorologist, started when he was just 10 years old. In 1967, an F-4 tornado went through Oak Lawn, Illinois, just a 1/2 mile from where Tim and his family lived at the time. It was a devastating event which killed 30 people and left a path of destruction. Tim gave an illuminating presentation on how he got involved with tornadoes and the TWIRL project at the University of Nebraska Lincoln’s Weatherfest on April 7th, available here, through UNL.

 

Tim Marshall presents TWIRL at the University of Nebraska Lincoln’s Weatherfest, April 7, 2017. 

 

Tim Marshall, P.E., Haag Principal Engineer

Tim Marshall is a structural engineer and meteorologist.  He has served as a Haag Engineer since 1983, assessing damage to 1000s of structures (particularly damage caused by wind and other weather phenomena). He has written numerous articles, presented countless lectures, and appeared on dozens of television programs in order to share his extensive knowledge re: storms and the resultant damage.  He is a primary author of many Haag Education materials, including the Haag Certified Inspector-Wind Damage course.  He is also a pioneering storm chaser and was editor of Storm Track magazine.  See his profile here.

 

April 2017 Blog Post

International roofing expo 2017

 

Haag recently attended the International Roofing Expo in Las Vegas. It was good to catch up with clients, Haag-Certified Inspectors, and others in the industry who stopped by our booth. Thanks to all who took the time to say hello.

We wanted to highlight some of the interesting products showcased at the IRE this year. These products caught our eye and we thought to pass the information along. This is not an endorsement, nor have we attempted to exhaustively detail every new and innovative product showcased there. Such an effort would have diverted us from the many other distractions on offer in Vegas.

Those of us who access steep-sloped roofs for a living or enjoyment rely in part on appropriate footwear to safely traverse them. Shoes specific for roof access have been available for years, but existing products were best suited for rough roof surfaces such as wood roofing and asphalt composition shingles. The shoes provided less traction on smooth roofing products such as metal panels. Steelwalker boots, with magnetic shanks are now available from Cougar Paws, intended for use on steel roofs. The soles should provide increased traction on steel roofing, as well as immediate notification of if the panels are steel.

Speaking of metal roofing, we ran across a novel metal roofing attachment scheme. Stealth Bond (Stealthbond.com) relies on an adhesive to bond 5V metal panels to metal batten strips mechanically fastened to the roof deck, resulting in no exposed fasteners. Several test installations have been made in Florida to date; code approvals are pending.

The roofing industry is dynamic. New products are introduced and products are discontinued for various reasons. These discontinued products still shed water on roofs; sometimes for decades after production was discontinued. Individual replacement of damaged discontinued roofing units can present challenges if the color and/or profile is no produced and reserved stocks are exhausted. However, there are options for custom fabrication of roofing units to match both color and profile. This option can be expensive on a per-unit basis but can be economical when compared to full roof replacement. We chatted with a composite tile producer, Brava Roof Tile (Bravarooftile.com), who has had good results with profile and color matching of discontinued or otherwise unavailable concrete, clay, synthetic, and slate roofing tiles.

DAN BEHRENS

Daniel B. Behrens, P.E.

Daniel Behrens graduated from the University of Minnesota with a B.S. in Civil Engineering. He is a Senior Engineer at Haag and is licensed as a Professional Civil Engineer in 13 states. Mr. Behrens is currently a member of the American Society of Civil Engineers and the American Institute of Steel Construction. Mr. Behrens has been with Haag since 2009, and has inspected and assessed damage to hundreds of roofs and structures. His primary areas of consulting are structural evaluations, roofing systems, general civil engineering evaluations, moisture source evaluations, and building envelope evaluations. Mr. Behrens helps develop and present continuing education seminars as an instructor for Haag. See his profile here.

Updated HCI Commercial Roofs- March 2017 Blog

Updated HCI-commercial roofs course

In March 2017, an updated version of the HCI-Commercial Roofs course will launch. The goal was to make the course more engaging for the attendees and provide more hands-on and direct learning experiences. We want the course to provide information and “tools” that will help the attendees in their day-to-day work tasks and also earn the Haag certification that will set them apart professionally.

The HCI-Commercial Roofs course covers the various common types of low-sloped membrane roof systems and metal roofing, as well as information on the severe weather events (hail and wind) that can damage roofs. Hands-on samples will be used to teach attendees how to identify insulation varieties and the low-slope membrane types. In learning groups, attendees will use the HPMG (Haag Panel and Membrane Gauge) to identify single-ply roof types and thicknesses. For the various roof systems, video segments will show proper installation and repair procedures. Multiple case studies will be presented to show how Haag engineers have made forensics evaluations on particular projects to determine whether observed damages were caused by construction defects, manufacturing issues, hail impact, or wind damage. Videos also will be shown of simulated hail impacts and the wind simulator machine in the laboratory of Haag Research & Testing. One segment of course will focus on the newer and growing segments of the commercial roofing industry including vegetative roof systems, liquid-applied roofing, and roof-mounted photo-voltaic systems.

The HCI-Commercial Roofs course is designed with several objectives in mind for our attendees. Upon completion of the course, the attendees will be able to identify the various components and materials used in typical low-sloped roof systems. For particular low-sloped roof systems, the attendees will be able to identify the type of roofing; identify conditions related to manufacture, installation, normal weathering, hail impact, wind forces, and mechanical contact; and the explain repair options and methodologies. Once damage has been identified to a roof system, attendees will learn techniques to estimate repair costs and compare the cost of repair to roof system replacement. Finally, the attendees will be learn methodologies to report the findings of their roof inspections and investigations.

If you have taken HCI-Commercial Roofs previously and are approaching your renewal time, this is a great opportunity to attend the updated course. Or, share this information with your co-workers and colleagues.

Richard F. Herzog P.E., Meteorologist, RRC, and Haag Principal Engineer

Richard Herzog’s primary areas of consulting are Roofing Systems, Building Envelope Systems, Evaluation of Wind Damage to Structures, Construction Defect Evaluations, Meteorological Investigations, Development of Hail Analysis Software, and Alternative Dispute Resolution.  He serves as a primary advisor in the creation of many Haag Education seminars and products.  See his profile here.