Comparison of Plywood Thickness Options for Home Renovation

If you have ever stood in front of a stack of plywood sheets wondering whether you need 9mm, 12mm, or 18mm - you are definitely not alone.

Choosing the right plywood thickness is one of the most confusing parts of a renovation project. Too thin, and shelves start sagging or cabinets feel flimsy. Too thick, and suddenly the project becomes heavier, harder to install, and more expensive than it needs to be.

In Australia, we are also seeing more homeowners, designers, and cabinetmakers move toward European plywood because of its cleaner finish, better stability, and more consistent quality compared with many lower-grade alternatives.

This guide explains the most common plywood thickness options used in home renovations, where each one works best, and how plywood differs from plyboard.

First: What Is Plywood?

Plywood is made by gluing together thin layers of timber veneer, with each layer running in alternating directions.

That cross-layered construction is what gives plywood its strength and stability. Unlike solid timber, it is less likely to twist, shrink, or warp over time.

High-quality European plywood - especially birch plywood from places like Finland, Latvia, and Estonia - is popular because it usually has more consistent cores, fewer internal gaps, cleaner edges, stronger screw holding, and better machining performance.

That is why architects and cabinetmakers often use it for lots of applications.

What Is Plyboard?

People often confuse plywood and plyboard, but they are not the same thing.

Plyboard usually has a core made from timber strips or battens, with thin veneer layers on the outside. It is lighter than plywood and sometimes cheaper, but it generally does not offer the same structural consistency or durability.

In simple terms:

• plywood = layers of veneer throughout the entire panel
• plyboard = timber strip core with thin veneer faces

Plyboard can work well for lightweight furniture or interior applications, but plywood is usually the better choice when you need strength, stability, and long-term durability.

For most modern renovations in Australia, plywood is the more versatile and reliable material.

Why Plywood Thickness Matters

Thickness affects almost everything from rigidity and screw holding to the overall feel of the finished project.

A shelf made from the wrong thickness might look fine on day one, then start bowing six months later.

On the other hand, using unnecessarily thick plywood can add cost and weight without giving you much practical benefit.

The best thickness depends on the multiple 'what ifs' and the type of project - how much weight it needs to carry, support spacing, potential , or moisture exposure, and even the look you want.

3mm Plywood

3mm plywood is very thin and flexible.

It is mostly used for:

• drawer bottoms
• cabinet backs
• decorative panelling
• curved surfaces
• lightweight backing panels

It is easy to cut and lightweight, but it is definitely not 'structural' in any case.

You would never use 3mm plywood for shelving or anything load-bearing.

6mm Plywood

6mm plywood is commonly used where you want a lightweight panel that still feels reasonably stable.

Typical uses include:

• wall linings
• ceiling panels
• caravan interiors
• furniture backing
• lightweight joinery

Many modern interiors use 6mm birch plywood because it creates a clean, minimalist look without adding too much weight. Can be used on spans  <300mm.