Top Takeaways from Popular Webinars

Apr 28, 2021 by Scott Hughes

OnBoard Newsletter | April 2021

by Scott Hughes and Alan Zeedyk

National Gypsum Company’s Construction Design Managers (CDM) recently hosted three webinars, broadcasting important information that pertains to nearly everything you design and build. If you weren’t able to attend, we’re sharing the top questions your peers asked during these sessions, our answers, and essential technical takeaways.

We could also provide a similar program for your team – either in your office or virtually. These are not sales pitches but applied insights that will help you plot out complex details of your projects. Your regional CDM is here to help, along with our 1-800-NATIONAL® team.

Now, to recap the recent webinars and technical information we think you’ll find useful:



The three main objectives for this course were:

  1. Understand the web-based UL design search tool, Product iQ, what it looks like and how to use it to search for your design criteria and to find other resources on the UL Product iQ website.
  2. Describe the test process gypsum board assemblies undergo and pass to be included in the UL Fire-Resistance Directories and the relationship of gypsum board core type to the tested assemblies.
  3. Outline the UL design minimum requirements and the alternate features that can be included or substituted within the parameters of the fire-rated design assembly.

Top Questions & Answers

Q: If I have an assembly (floor, ceiling, wall) and can't find it listed, what kind of assistance do you provide to find it?

A: Call 1-800-NATIONAL for assistance finding an appropriate UL design to meet your requirements. They can also help you with a prescriptive method if no UL-tested assembly is available. During the webinar, we addressed using the Product iQ assembly tool to help narrow the list of assemblies meeting your selected requirements.

Q: Contractors often ask if they can substitute one manufacturer’s gypsum board with another manufacturer’s product. What is the best guidance to offer contractors who ask this question?

A: The contractor must construct the UL fire-rated design according to the products approved and tested per the assembly description. Alternate fire-rated assemblies are typically available from multiple manufacturers with similar components and hourly rating. The contractor should facilitate and submit a UL rated assembly of the same hourly rating and similar components with preferred manufacturer’s products listed. We have developed a UL Design Comparison Chart that can help you. Contact your Construction Design Manager to find out about this comparison resource.

Q: Are there any floor/ceiling assemblies that have been tested with full-depth insulation?

A: The assembly component keynotes listed in the tested UL assembly indicate the minimum level of insulation required. You can add more if it does not exceed the depth of the cavity. National Gypsum has two assemblies that have unlimited insulation: P533 for roof/ceiling assembly and L588 for floor/ceiling assembly.

Click HERE for all the "Understanding the UL Fire-Resistance Directories" Q&As.



The three main objectives for this course are:

  1. Understand how a STC rating is calculated and what this value tells us about the reduction of sound between spaces.
  2. Outline the role each component of a tested assembly plays in reducing sound transmission and the advantages of using acoustically enhanced gypsum board in thin wall technology.
  3. Illustrate most common approaches to achieve high STC partitions and cost comparisons between these designs.

Top Questions & Answers

ceiling board

Q: Please clarify the difference between "lab tested" STC and "field tested" STC?

A: The Sound Transmission Class (STC) is a single number rating of the effectiveness of a material or construction assembly to attenuate the transmission of airborne sound. The STC provides an indication of how loud transmitted sound is perceived to be by the listener. STC values are measurements that indicate a laboratory tested assembly. Field Sound Transmission Class (FSTC) references the same measurement of assemblies, but they are tested on site in the installed location. The field-tested values are normally lower due to building movement and different installation methods.

Q: Are wood studs typically better than metal studs for STC?

A: Light gauge steel studs (25-gauge metal) provide the best sound protection. Wood studs are more rigid and transfer sound more easily. Our SoundBook® 2.0 lists many examples of steel and wood partition assemblies with stud spacing at 24" o.c. and 16" o.c.

Q: With staggered stud wall construction, separation of electrical boxes into different cavities is not feasible and putty wrap on the boxes becomes more important. Does the staggered wall configuration without putty on boxes still outperform single stud wall configuration?

A: Sound walls are tested without penetrations. The lab testing for a single wood stud wall 16" o.c. with 5/8" Type X on both sides is a 35 STC. A staggered stud assembly using the same materials achieves a 45 STC. Adding a layer of SoundBreak XP Wall® Board to one side of the staggered wall assembly tests to a 53 STC. Unless the staggered wall assembly had an unusual number of electrical boxes or other penetrations, it will outperform a single stud assembly using the same materials.

Click HERE for all the "Acoustically Enhanced Gypsum Board" Q&As.



The three main objectives of this course are:

  1. Review features of the fiberglass mat gypsum products and associated exposure warranties.
  2. Describe the ability to shorten a construction cycle by installing fiberglass mat gypsum products in pre-rock applications.
  3. Define the applicable ASTM product and mold-resistance standards, as well as code requirements when using glass mat gypsum products in sheathing and roof coverboard applications.

Top Questions & Answers

high performance gypsum

Q: Are there tested assemblies for repairs? For example, a ladder falls into the panel and puts a hole in it. Code officials and jurisdictions want certified repairs.

A: The Gypsum Association document GA-225-19, “Repair of Fire-Rated Gypsum Panel Product Systems,” covers this topic in detail. A short video illustrating fire-rated gypsum system repairs is also available.

Q:Can interior and exterior fiberglass mat boards be exposed to weather for up to 12 months?

A: Yes, interior and exterior fiberglass mat gypsum panels can be exposed for 12 months if installed in a vertical application. Gold Bond® eXP® Interior Extreme can be hung on the interior before the building is completely enclosed.

Is a full skim coat required to finish the Gold Bond® eXP® Interior Extreme product? Is this product easy to cut?

A: Gypsum Association document GA-214-15,“Recommended Levels of Finish Gypsum Board, Glass Mat & Fiber-Reinforced Gypsum Panels,” recommends skimming any glass mat interior product to a Level 5 finish in aesthetic areas and areas in critical lighting conditions. Gold Bond® eXP® Interior Extreme cuts and scores the same as paper-faced gypsum board products

Click HERE for all the "High Performance Gypsum Board" Q&As


If you missed our webinars and would like to schedule a learning opportunity for your team, either at your office or virtually, contact your National Gypsum Construction Design Manager. They will keep your team engaged. Along with our easy-to-navigate websites, technical 1-800-NATIONAL® hotline, and other valuable resources, your CDM is here to help you design and build better.

“Our technical marketing team has more than 175 years of combined industry experience. Collectively, we have worked on many different projects throughout the country and are available to help with product selections or tough applications.”

Amy Hockett, AIA


Amy Hockett, AIA

Manager, Architectural Services & SustainabilityNational Gypsum


It’s easier than ever to find the products and tools you want via National Gypsum Company’s new digital multi-website platform. This family of five websites is dedicated to the National Gypsum®, Gold Bond®, PermaBASE®, ProForm® and PURPLE brands, allowing you to get the information you need right away.

While all sites are quickly accessible through this website, you can also connect directly to,, and

Be sure to visit the refreshed Design & Resource Center, which will help support your team with the following and more:


Atrium Health Pineville

Project: Atrium Health Pineville in Pineville, NC (a suburb in south Charlotte)

Architects: Wright McGraw Beyer, Charlotte, NC

Contractor: Rodgers Builders, Charlotte, NC

Drywall Subcontractor: Southern Wall Systems, Atlanta, GA

Owner: Atrium Health, a nonprofit health system with more than 1,500 care locations

Atrium Health is expanding its Pineville hospital with an additional 236,000-square-foot, eight-story tower and 38 new acute-care beds. A portion of this project has already been constructed using modular panels, incorporating 40,000 square feet of PermaBASE® Cement Board and Gold Bond® eXP® Sheathing. The thin brick method using PermaBASE saved time and labor costs versus the traditional cement bed method over exterior glass mat sheathing. According to Eddie Neel, PermaBASE marketing manager: “The majority of the exterior panels of the hospital were installed within 30 days.”

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