GAF Timberline HDZ Helps Renner Roofing Protect Customers in Minnesota

By Dawn Killough 06-07-2021
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We recently interviewed Nick and Tony Renner of Renner Roofing, a GAF Master Elite* contractor in Welch, Minnesota. They started their company in 2016, serving the mostly rural region of southern Minnesota. We asked them about the history of their company and their experience with Timberline®HDZ™ Shingles.

GAF: Tell us about your company's history and background with using GAF products.

Renner Roofing: When we started our company, we knew we wanted to focus on providing only one manufacturer's system. We selected the GAF roofing system because of the quality of the material and the fact that they stand behind their products with strong warranties. Our business has thrived—we're installing 150 to 300 roofs a year, and 2020 has been our best year yet.

GAF: What are your main priorities when working on a project?

RR: In addition to ensuring the safety of the workers, we want a good product, quick installation, and a quality system. We feel we've found that with Timberline® HDZ™ shingles, which we use on 99% of the projects we perform.

GAF: What are the benefits of using Timberline® HDZTM shingles?

RR: The top concern for most of our customers is shingle blow offs. It's standard to have wind gusts between 40 and 60 miles per hour in western Minnesota, and we've never had a customer report losing a shingle since we started using Timberline® HDZTM. We typically install a GAF roofing system that includes FeltBuster®, Pro-Start® starter strip shingles, Cobra® ridge vents, TimberTex® ridge cap shingles, and Timberline® HDZ™ shingles so that the shingles qualify for the GAF WindProven limited wind warranty**. The warranty provides coverage for shingle blow offs, which means peace of mind for us and homeowners.

Speed of installation is another benefit of using Timberline® HDZTM shingles. The expanded nailing area helps us fasten the shingles faster, and the quick sealing glue strip helps reduce the risk of blow offs.

For us, Timberline® HDZTM is the best product.

GAF: Do you have any tips for roofing contractors using GAF products?

RR: We have three tips for anyone using Timberline® HDZTM:

  1. Make sure you have a spotless roofing surface. Remove all nails and debris from the roofing deck before installing the underlayment. The roof system should be tight and flat to the roof deck to help prevent interference with the shingles properly sealing.
  2. The underlayment must always be installed properly to help avoid the potential for wrinkles that can create a poor finished appearance.
  3. Don't lay pallets of shingles across ridges on steep slopes. The combination of heat and the slope can create creases or bubbles in the shingle that interfere with sealing. Make sure all shingles are laid flat while waiting for installation.

GAF: What has been your experience with Timberline® HDZTM in cold weather?

RR: Minnesota is no stranger to cold weather, so we've installed it in temperatures down to 40 degrees, but we don't recommend installing at temperatures below that. We've installed plenty of roofs in the 40- or 50-degree Fahrenheit range and haven't had any issues with the shingles sealing.


The Renners trust the GAF Timberline® HDZTM roofing system to help protect homes from wind and rain. They are passionate about the GAF system—after all, they did their research, and their customers are just as happy with their choice.

This interview was edited and condensed.

*Contractors enrolled in GAF certification programs are not employees or agents of GAF, and GAF does not control or otherwise supervise these independent businesses. Contractors may receive benefits, such as loyalty rewards points and discounts on marketing tools from GAF for participating in the program and offering GAF enhanced warranties, which require the use of a minimum amount of GAF products.

**15-year WindProven™ limited wind warranty on Timberline® Shingles with LayerLock™ Technology requires the use of GAF starter strips, roof deck protection, ridge cap shingles, and leak barrier or attic ventilation. See GAF Roofing System Limited Warranty for complete coverage and restrictions. Visit for qualifying GAF products.

Dawn Killough is a freelance writer in the construction, finance, and accounting fields. She is the author of an ebook about green building and writes for construction tech and green building websites. She lives in Salem, Oregon with her husband and four cats.
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