Building Knowledge

10 drywall ceiling tips from the experts at National Gypsum

Oct 7, 2024

From sag resistance and installation guidance to finishing and control joints, let’s solve your ceiling dilemmas

Like wall systems, ceilings face challenges related to expansion and contraction, gravitational forces, lighting, acoustics and fire exposure. With so many variables to consider, ceilings often elicit a wide range of questions from designers. In this article National Gypsum Company’s 1-800-NATIONAL^® Construction Services team answers the most asked questions about drywall for ceilings.

1) When should I specify “sag-resistant” gypsum board for a ceiling?

The term “sag resistant” only applies to 1/2” gypsum board products and means it surpasses the minimum sag resistance requirements for 5/8” gypsum board. To avoid confusion, architects should avoid specifying 5/8” sag resistant gypsum board, since there is no specialty 5/8” product on the market advertised as being sag resistant.

Choose Gold Bond® High Strength LITE® Gypsum Board, which is sag resistant, if you’re using 1/2" gypsum board on the ceiling and any of the following conditions exist:

A water-based texture will be applied to the finished ceiling.
The framing spacing is 24" o.c. as opposed to 16" o.c.
The weight of the installation will exceed 1.3 psf.

Follow the GA-216-2021, Application and Finishing of Gypsum Panel Products, for installation requirements and restrictions when constructing gypsum board ceilings.

Pro Tip: High Strength LITE offers a significant advantage: It is easier to handle and transport on the jobsite because it’s 25% lighter than standard gypsum board, reducing fatigue for drywall installation crews.

2) Does the direction of gypsum board installation affect the ceiling’s performance?

Just as wood is stronger in the grain direction, gypsum boards are stronger in the direction they move along the conveyor belt during production, known as the “machine direction.” That means the board is stronger along its long axis, so it should be installed perpendicular to ceiling framing members to minimize sag.

In addition, perpendicular installation results in better performance during fire tests, and it is easier to align the 4-foot end on lumber that is often not straight than it is the long edge of the panel.

3) How can I minimize ceiling cracking?

Use resilient channels to structurally separate the gypsum panel ceiling from the framing above. Decoupling the ceiling from the framing allows for each to expand or contract independently and reduces the stress on the gypsum panel ceiling caused by deflection of the framing.

4) What’s the recommended spacing for control joints in a ceiling?

Walls need a control joint every 30 feet. Similarly, a ceiling over 30 feet also needs a control joint, unless it has perimeter relief, which allows for expansion along the edges. Perimeter relief can be accomplished by separating the ceiling from the wall completely or with a slip connection that allows for movement of the ceiling in relation to the wall. When perimeter relief is employed, the control joint spacing is increased from 30 feet to 50 feet.

Resource alert: Learn the guidelines for control joint installation.

5) What products should I use for fire-rated floor- and roof-ceiling assemblies?

Most UL designs for floor-ceiling and roof-ceiling assemblies require a specialty Type X gypsum board with special additives for increased fire resistance. For ceilings, we recommend the following options:

Resource alert: Read our blog article explaining the difference between Type X or Type C gypsum boards.

6) How do I build a fire-rated ceiling without a floor or roof component?

When you need to construct a horizontal fire barrier such as a floor-ceiling or roof-ceiling assembly and cannot access the deck above due to mechanical equipment or other obstructions, construct a horizontal membrane. Horizontal membranes are tested just like floor- and roof-ceiling assemblies except without an applied load. Often referred to as tunnel construction for their use in rated corridors, they can also be used to construct duct enclosures, stair soffits, mechanical shafts or fire-rated floor- and roof-ceiling assemblies where the floor or roof components do not comply with a tested assembly.

Resource alert: Read this article about the wide variety of horizontal membrane options for both 1- and 2-hour ceiling systems available from National Gypsum.

7) Why is the level of finish important for ceilings?

Consider a Level 5 finish on ceilings because they are subject to oblique lighting, whether it is sunlight from a window, artificial light from fixtures mounted on the walls or hanging light fixtures that reflect light off of the ceiling surface. Even when there’s no visible sag in the ceiling, critical lighting can show gypsum board joints or tiny imperfections, so a Level 5 finish is essential.

Resource alert: Read this article to better understand the five levels of finish.

8) When should I use 5/8" vs. 3/4" SoundBreak on ceilings?

Use 5/8" Gold Bond® SoundBreak® XP® Fire-Shield® Gypsum Board in non-fire-rated ceiling applications or as an additional layer to fire-rated floor-ceiling and roof-ceiling assemblies where sound transmission is a concern.

Use 3/4" Gold Bond® SoundBreak® XP® Fire-Shield C™ Gypsum Board in specific UL floor-ceiling assemblies to achieve a fire-rating and sound reduction with a single gypsum board.

9) What products should I use for exterior soffits?

All of the products in the Gold Bond^® XP^® or Gold Bond^® eXP^® families of gypsum board products are mold- and moisture-resistant and approved for use in exterior soffits.

For soffits with direct applied finishes, eXP products are recommended.
For soffits that will be painted, XP products are recommended.

Painted soffits constructed with eXP products will require a skim coat of setting compound, such as ProForm ^® Quick Set Lite™ Setting Compound, to provide a smooth surface.

Resource alert: Learn how to choose the appropriate substrate for exterior soffit s.

10) What product should I use for the ceiling of my commercial kitchen?

Gold Bond^® Gridstone^® Gypsum Ceiling Panels, available in black or white, meet USDA requirements for a smooth, durable, easily cleanable surface. To clean, use a light scrubbing action with a cloth, sponge or soft brush dampened with water mixed with mild soap or detergent. Be sure to test the cleaning agent on a hidden area or scrap piece to ensure it does not damage the panel’s vinyl surface.

Have more questions? Reach out to the experts at 1-800-NATIONAL Construction Services for technical advice and product insights.