A Complete Guide to Drywall Thickness: What You Need to Know

Most homeowners focus on paint colours and finishes. But Professionals focus on drywall thickness first.

Why? Because drywall thickness determines how well your walls hold up over time. It’s one of those small decisions that quietly affects strength, durability, sound control, and fire safety.

If you’re planning a renovation or starting a new build, understanding how thick drywall is – and which thickness works where – can save money and future repairs.

What is Drywall?

Drywall consists of gypsum plaster encased between two sturdy sheets of paper. It is primarily used for constructing walls and ceilings, being fastened to metal or wood studs with nails or screws.

Before the invention of drywall, builders relied on layers of wet plaster, which had to dry before the next coat could be applied.

Drywall, however, doesn’t require water and can be installed much more quickly, significantly speeding up the construction process.

Specialty Drywall Variants

• Moisture-Resistant Drywall: Often referred to as green board, is designed for areas prone to humidity. It is perfect for bathrooms, kitchens, and laundry rooms as it can withstand the moisture present in these spaces.
• Mold-Resistant Drywall: Mold-resistant drywall is specially made for basements and regions with high humidity. It’s great for homes in humid environments as it helps prevent mold and mildew growth.
• Soundproof drywall: It is the best option for home theaters, recording rooms, and multi-family housing where sound insulation is essential. It helps reduce noise transfer between rooms

It is not recommended for standard residential walls, as the extra cost and weight may be unnecessary for typical living spaces.

Standard Thickness of Drywall

Drywall comes in several thicknesses, each with specific uses depending on the area of installation, structural requirements, and local building codes.

Most construction projects use four main drywall thicknesses. Each has specific structural and practical uses.

1. 1/4-Inch Drywall (6.35 mm)

1/4 Inch Drywall is the thinnest option available, commonly used as a skimming material over existing surfaces. It’s perfect for covering old or damaged walls, refreshing a room’s appearance, and hiding imperfections.

Its flexibility makes it ideal for creating curved walls. However, it lacks structural strength and is not suitable for new framing or ceiling installations.

Best For	Not Recommended For
Covering existing walls Creating curved surfaces Minor repairs Adding an extra layer over existing drywall	New construction or framing Ceiling installations High-impact areas

2. 3/8 Inch Drywall (9.5 mm)

3/8 Inch Drywall is slightly thicker than 1/4 inch and is commonly used for repairs and remodeling projects. It can be applied over existing drywall for added strength or used in light partition applications.

While it offers more durability than 1/4 inch, it’s still not ideal for ceiling installations without proper support.

Best For	Not Recommended For
Remodeling projects Double-layer installations Wall patches	Ceilings with wide joist spacing Heavy impact areas

3. 1/2 Inch Drywall (12.7 mm)

1/2 Inch Drywall is the most commonly used thickness for residential construction. It offers a good balance of strength, cost-effectiveness, and ease of installation.

It’s suitable for most interior walls and ceilings where standard durability is needed, typically used for walls and ceilings with 16-inch stud or joist spacing.

Best For	Not Recommended For
Interior residential walls Ceilings with standard joist spacing Living spaces and bedrooms Basement finishing	Heavy-duty commercial or industrial use Wide ceiling joist spacing (24 inches apart) Fire-rated walls

4. 5/8 Inch Drywall (15.9 mm)

is thicker and heavier, making it ideal for ceilings with 24-inch joist spacing. It is also commonly used in high-traffic areas, fire-rated walls, and commercial applications.

This thickness is stronger, more resistant to sagging, and provides better soundproofing properties. Many building codes require this thickness in areas where fire resistance is necessary.

Best For	Not Recommended For
Ceilings with 24-inch joist spacing Fire-rated walls High-traffic or commercial areas Soundproofing	Standard interior walls in smaller spaces DIYers on a budget Low-humidity areas

Which Drywall to Use for Different Applications

The choice of drywall depends on the application, and using the right type ensures better results. Here’s a breakdown of which drywall to use for specific situations:

• For Standard Walls and Ceilings: Use 1/2 inch drywall for most standard interior walls and ceilings. It’s affordable, easy to install, and provides sufficient strength for everyday use.
• For Ceilings with Wider Joist Spacing: When the joists are spaced 24 inches apart, 5/8 inch drywall should be used to prevent sagging. This provides more support and extra durability, especially in larger rooms.
• For High-Impact Areas: If the drywall will be in areas with high traffic, such as hallways or staircases, opt for 5/8 inch drywall. This thickness is more resistant to dents and wear, providing better durability
• For Moisture-Prone Areas: In bathrooms, kitchens, and basements, use moisture-resistant drywall. It is typically available in 1/2 inch or 5/8 inch thicknesses and helps protect against mold growth in damp environments.
• For Fire Safety: Use 5/8 inch Type X drywall for walls that need to meet fire-resistance standards. This type of drywall is typically required for garage walls and shared walls between living spaces.
• For Soundproofing: If noise reduction is essential, such as in home theaters or apartments, use 5/8 inch soundproof drywall. It helps to block sound transfer between rooms and improves acoustics.

How to Measure and Identify Drywall Thickness

When it comes to drywall, knowing the thickness is important for your project. Whether you’re installing it or replacing an old panel, measuring the thickness correctly can make a big difference in how your walls or ceilings turn out.

Measuring Drywall Thickness

Measuring drywall thickness is pretty easy! Here’s how to do it:

Step 1: Use a Tape Measure or Ruler

Take your tape measure and place it along the edge of the drywall panel. Make sure to measure from one side of the panel to the other. Drywall thicknesses are usually measured in inches.

Step 2: Check for Common Sizes:

Most drywall comes in common thicknesses:

• 1/4 inch (for small, curved spaces)
• 3/8 inch (less common)
• 1/2 inch (standard for walls)
• 5/8 inch (for ceilings and fire-rated areas)

If you get a reading that’s close to any of these sizes, you’ve probably found your answer!

Step 3: Measure Multiple Spots

Drywall can sometimes vary slightly in thickness along different parts of the panel. Measure in a few places to get an average thickness.

Identifying Drywall Thickness

Sometimes, you don’t have to measure the drywall yourself. Here’s how you can identify the thickness by looking at the panel:

• Labels: Many drywall sheets come with labels printed on the back or edge. These labels often show the thickness and type of drywall (like 1/2 inch or fire-rated).
• Weight: Thicker drywall is heavier. If the panel feels unusually heavy for its size, it’s likely 5/8 inch or another thicker version.
• Feel the Edge: If you have access to the edge of the drywall, you can feel the thickness by running your fingers along it. A 1/2 inch panel will feel about as thick as the width of a pencil, while 5/8 inch will feel a bit thicker.

So next time you’re working with drywall, whether for new installation or a repair, use these easy methods to find out how thick it is. This will help you get the job done right!

Conclusion

Choosing the right drywall thickness is key to ensuring your walls and ceilings are durable, safe, and functional. For most residential needs, 1/2 inch drywall is ideal.

However, for wider ceiling joist spacing, high-traffic areas, or spaces requiring fire resistance, 5/8 inch drywall is a better choice.

By understanding the various drywall thicknesses and their applications, you can make informed decisions that will result in durable and safe walls and ceilings for your home or building project.