Tile Over Plywood vs. Cement Board

When it comes to tiling, the surface beneath your tiles matters more than you might think. Choosing between tile over plywood and cement as your tile substrate can greatly impact your project. 

It ensures that your tile underlayment supports your tile and can withstand the test of time, preventing issues like cracked, loose, or broken tiles. 

In this post, we'll compare tiling over plywood and cement board, outlining the key differences between the two so you can make the right choice for your tile installation. 

Material Composition 

Plywood involves gluing thin sheets of wood veneer together using adhesives. The type of wood used varies but generally is hardwood or softwood. 

However, cement boards are rigid panels made from cement, fillers, cellulose, and mica. It also contains small amounts of PVA and aluminum stearate. 

The difference is that plywood uses wood and is relatively flexible, whereas cement board is exceptionally stable and durable. 

Moisture Resistance 

Moisture tends to wreak havoc on building materials, causing them to warp, deteriorate and expand. Plywood is highly prone to moisture damage, even though certain types may have water-resistant coatings. 

In contrast, cement boards are highly resistant to water, making them an excellent choice for areas with frequent exposure to moisture, like bathrooms, kitchens, and laundry rooms. They won't deteriorate or expand like plywood, and you won't have to deal with a potential mold problem. This also reduces the risk of grout or tile failure. 

Most people enjoy the versatility of cement boards. For example, LiLi Tile tiles work with both wet and dry areas, whether in a residential or commercial space. 

Stability and Durability 

Cement boards offer stability and rigidity that tile over plywood simply can't match. It won't even crack if your subfloor shifts or flexes. 

Besides durability, the cement board functions well for extended periods. This gives you the luxury of a stable surface that remains intact for a long time. 

Unfortunately, plywood is susceptible to flexing and warping from humidity or changes in temperature. Therefore, plywood may not be best for moisture-prone and high-traffic areas, but is better suited for dry areas like wall installations where moisture isn't a concern. 

Installation Process 

When installing tile over plywood, you'll likely need to take extra steps to ensure it stays on properly. For example, a layer of cement backer board is often used as additional support for a stable and moisture-resistant surface. Sometimes, a special type of thin-set mortar is needed that sticks to wood surfaces better. 

Cement boards are relatively straightforward to install. Simply secure the panels to the subfloor or wall studs and apply fiberglass mesh tape for seam reinforcement. Besides that, you're ready for the tile installation once the underlayment has been implemented. 

Cost 

Generally, tile over plywood is a more affordable option for flooring, but it won't last as long as its cement counterpart. That said, it varies depending on the material's thickness and size. 

In wet areas like bathrooms, you may need to invest in a waterproofing membrane or moisture barrier to protect the plywood from moisture, which can add to the overall cost. 

Also, consider the total usage and lifetime value you would get from each since cement boards can last longer and tend to better withstand heavy loads and foot traffic. 

Adhesion 

Another big advantage of cement boards over plywood is that they tend to be more adhesive, especially for attaching tile to vertical applications. The smooth finish of cement boards allows for seamless adhesion while also being able to bear a lot of weight. 

Plywood is rougher, doesn't stick as well, and bears less weight. Sometimes, a thin-set mortar (often called a bonding coat or scratch coat) is used to help plywood adhere better to tiles. 

Frequently Asked Questions

What Happens if You Put Tile Directly on Plywood?

If you lay tile on top of plywood, it'll expand over time, causing the tiles and grout lines to possibly crack and damage. The tile can't properly stick to wood as it can with concrete. Instead, lay a cement board on top of the plywood first or use a decoupling membrane. 

What Do You Put Over Cement Board Before Tiling?

Before tiling over the cement board, apply a layer of thin-set mortar to the surface of the cement board. This creates a strong bond between the cement board and the tile. Also, use fiberglass mesh tape to cover the seams between the cement board sheets for reinforcement. 

Tiling Over Plywood or Cement Board? LiLi Tile Has You Covered!

Choosing the best substrate for your tile installation ensures integrity and long-term performance. Plywood may be the more budget-friendly option, but it is less moisture-resistant and stable than cement board. 

Cement board is better for areas with movement, water exposure, and subfloor imperfections, like kitchens, bathrooms, and laundry rooms. 

But plywood is an acceptable choice if your subfloor is dry and stable. Ultimately, the decision comes down to the scope of your project, location, and budget. 

If you want beautiful tiles on top of your stable foundation of substrates, look no further than LiLi Tile. We offer a remarkable range of tiles to bring your tiling vision to life.