Drywall Thickness
In addition to specialized types of drywall board for specific applications – like mold-resistant “green board” for use in damp environments, for example – drywall sheets are available in several different standardized thicknesses:
¼ inch
3/8 inch
½ inch
5/8 inch
Different thicknesses are useful in different kinds of applications and understanding how to choose the right drywall thickness can level up your drywall craftsmanship, especially if you’re a DIYer.
Best Thickness for General Use
Best Thickness for Curved Surfaces or for Laminating Existing Surfaces
¼-inch drywall – the thinnest kind available – isn’t as commonly used as other thicknesses because it’s more fragile than thicker boards. On the other hand, it’s considerably lighter and more flexible than other kinds of drywall. That makes it a good fit for curved surfaces where its flexibility is an advantage.
It’s also great for situations where you might want to double-wall. For example, you can add it to an existing drywall surface to add an extra layer of sound insulation without tearing out what’s there.
While you might be tempted to use ¼-inch drywall on ceilings because its light weight makes it easy to lift, it’s a poor fit for ceilings because it sags more easily than other boards due to its flexibility.
Best Thickness for Patches
3/8-inch drywall is a good choice for remodeling partitions or creating patches. It’s slightly thinner than standard ½-inch drywall but sturdier and more rigid than ¼-inch drywall, making it a good choice when you’ll need to add it to an existing wall or surface where the plaster has worn away.
Decades ago, 3/8 drywall was the standard thickness, so depending on when a home or building was constructed, some applications may require 3/8-inch drywall. Because it is comparatively rare with respect to ½-inch drywall, 3/8 drywall can be hard to find (or completely unavailable) in any panel size besides 4×8.
Best Thickness for Ceilings and Fire-Rated Assemblies
Extra-thick 5/8-inch drywall is already more fire-resistant than its thinner cousins thanks to the extra-thick material. However, most manufacturers produce this thickness in an even more fire-resistant form in order to conform to building codes for fire rating and you’re unlikely to find 5/8-inch drywall that isn’t either Type X or Type C for fire-rated assemblies.
These special types of drywall have additives that improve their performance in a fire. Type X has fiberglass reinforcement that reduce the development of cracks as the board burns, allowing it to perform longer without failure. Type C boards have even more fiberglass reinforcement and they also contain a material that expands in a fire at roughly the same rate that the drywall board shrinks, further reducing cracking while increasing stability and time to failure.
In addition to their fire-resistant properties, 5/8-inch boards are also stiffer, which makes them a good option for ceilings, where they are less prone to sagging than other thicknesses of drywall board – especially if you plan to add a heavy texture. Like ½-inch drywall, 5/8 drywall is available in a variety of sizes, starting from 4×8 and going up. Its thickness may also make it more appropriate for commercial applications or situations where noise isolation is a concern – like shared walls of duplexes.
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