MaX 12 and MaX 16 with GridMarX contribute to smoother inspections

Dec 12, 2023

Learn about documentation from National Gypsum Company for code inspectors seeing GridMarX in the field

Building code inspections can be a source of stress for both contractors and inspectors. The safety and reliability of the buildings where we live, work and play rely on many different tested and approved systems coming together in the right way. Anyone who has watched television coverage of communities in ruins after natural disasters knows the value of adherence to building codes.

That’s why National Gypsum Company strives to create installation improvements, such as the MaX 12® and MaX 16® fastener patterns with GridMarX® installation guide marks, that not only make installation easier and faster but also ease the inspection process.

MaX 16 MaX 12 Fastener Pattern Card
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What makes MaX 12 and MaX 16 with GridMarX different?

The industry standard fastener pattern for UL fire-rated walls is 8" on-center (horizontal application) and 8" o.c. perimeter/12" o.c. field (vertical application). The MaX 12 and MaX 16 fastener patterns use fewer fasteners in UL fire-rated walls, which saves installers time, as well as labor and materials costs.

  • MaX 12, the industry’s first 12" o.c. optimized fastener pattern for single-layer, 1-hour UL fire-rated wall assemblies on steel framing spaced 24" o.c., uses a fastener every 12" throughout the perimeter and field of the board.
  • MaX 16, the industry’s only 16" o.c. optimized fastener pattern for single-layer, 1-hour UL fire-rated wall assemblies on steel framing spaced 16" o.c., uses one fastener every 16" throughout the perimeter and field of the board.

“GridMarX guide marks are printed on the board and provide for a more efficient and accurate fastener pattern placement. This can be especially helpful during building inspections, as inspectors will be able to quickly identify any issues with the installation of the drywall.”

Mark Chapman


Mark Chapman

Senior Manager, Construction ServicesNational Gypsum Company

How do MaX 12 and MaX 16 with GridMarX help with quality control and inspections?

GridMarX installation guide marks are visual indicators of stud location and fastener spacing. They are printed on the face paper parallel to the long edge every 4" along each edge, 16" from each edge and at 24" down the center of the board.

Code inspectors can easily verify the gypsum board is correctly attached to the studs — identifying correct screw patterns — their inspection takes place before drywall finishers apply joint compound.

GridMarX simplifies inspections:

  • It provides a visual reference of stud location.
  • Inspectors can verify fastener spacing without having to measure.
  • It enables inspectors to confirm that the boards are properly attached to studs.

Clemson University used Gold Bond® XP® Gypsum Board on its new College of Business. Paul Borick, project manager - capital projects, Clemson University, said code officials like GridMarX because it gives them peace of mind that the screws are correctly spaced.

“They can come out and see screw, screw, screw,” Borick said, mimicking a code inspector's visual review of screw placements. “Then the accuracy — I think that's why the code enforcement guys like it so much because they know what they're getting."

Watch the full Clemson University story to better understand how GridMarX installation guide marks save installers time and boost screw placement accuracy.


Construction practices evolve over time and are sometimes handed down informally, so when a new technique, such as MaX 12 and MaX 16 with GridMarX, arrives on the scene, building inspectors unfamiliar with the new fastener pattern may be cautious about giving their approval.

UL Evaluation Reports familiarize building code inspectors with the MaX 12 and MaX 16 fastener patterns.

The UL Evaluation Reports provide official documentation of third-party testing to specific standards or requirements for building products. The MaX 12 and MaX 16 with GridMarX report (UL ER R3501-03) covers the use of the following products for use in 1-hour UL fire-rated wall assemblies using the MaX 12 or MaX 16 fastener patterns.

These products have been tested using the MaX 12 and MaX 16 fastener patterns as a component in 12 UL 1-hour fire-rated assemblies for non-load-bearing walls.

MaX 16 1-hour UL Design
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  • UL Design V438
  • UL Design V450
  • UL Design V482
  • UL Design V483
  • UL Design V486
  • UL Design V488
  • UL Design W417
  • UL Design W421
  • UL Design W444

In addition to describing the fastener patterns, the reports include diagrams showing GridMarX installation guide marks and MaX 12 and MaX 16 fastener patterns for vertical or horizontal gypsum board installation.

Learn more about what’s included in UL Evaluation Reports.

Inspection assistance is a phone call away.

Download and print a copy of the UL Evaluation Reports for reference during the inspection. And if your building code inspector has additional questions, call 1-800-NATIONAL® Construction Services to talk to a technical expert.