Do You Need Plywood Under Quartz Countertops?

Do You Need Plywood Under Quartz Countertops

Do you need plywood under quartz countertop? This is a question that many people ask, and the answer varies depending on your project. In this article, we are going to explain the different ways that plywood can be used with quartz, and why it may or may not be necessary for your specific project.

Quartz countertops with thickness over 1 inch will not need plywood to support them, but if your quartz is less than an inch thick, it will be best to err on the side of caution and install plywood backer board – even though the quartz will hold up fine.

There are different types of plywood that may be used under your quartz countertops. Particleboard and some types of MDF will work well with quartz, while some other types of plywood will not. 

Keep reading to find out more!

What Is Quartz Countertop?

Quartz countertops are man-made material that is made to look like stone. The name comes from the fact that quartz particles are crushed into a fine powder, then mixed with resins and pigments to create a solid, durable material. 

Quartz countertops are made of a composite material that is usually composed of more than 90% quartz. 

Resins and pigments make up the remaining percentage, and the result is a solid, durable countertop that can be manufactured to mimic many types of natural stone.

Another way to put this is the result is a man-made product that is visually similar to natural stone but is much easier for installers and homeowners alike.

What Is A Plywood?

Plywood is a type of engineered wood product that is made from thin sheets of solid wood, glued together to form panels with the thickness and grade desired by the manufacturer. 

Plywood has traditionally been used as an exterior siding material, but it also is often found in interior walls for insulation and sound control because it’s relatively fire-resistant and inexpensive. 

Engineered with tongue and groove edges for easy installation over studs or joists, plywood can be nailed directly onto wall framing with regular nails or screws (nails must penetrate at least 3/8 inch into framing) or attached using adhesive (such as construction adhesive). 

Plywood typically comes in 4 x 8-foot sheets; if you’re using it on a wall, you’ll need to miter the edges so they fit together.

What Is Plywood Used For In A Countertop?

Plywood is often used under quartz because it can be installed in a variety of thicknesses depending on the needs and preferences of the homeowner. 

For example, a homeowner may choose to use plywood for their countertops because it’s less expensive than other options, such as using solid surface countertops. 

It’s also a good option for homeowners who are concerned about cost but want the durability of other materials, such as quartz. 

Laminate countertops are another popular option, but laminate is not as durable and can be damaged when exposed to water.

Factors To Consider Before Using Plywood Under Quartz Countertop

There are many factors you have to consider before using plywood under quartz countertops. Below, I’m going to share with you some of the factors that I think are most important.

1. Manufacturers Instructions

If you’re not sure whether or not plywood is required for your quartz countertops, I recommend checking with the manufacturer to see what they recommend. 

They may have a list of approved installation methods and materials, or they may be able to provide you with more information about their specific product. 

If the manufacturer includes plywood in their installation instructions, it’s usually best to follow those guidelines instead of trying to use another material.

2. Type Of Quartz Countertop

The first thing that you need to consider is the type of quartz countertop. There are two types, high-pressure laminate (HPL) quartz, and engineered stone. 

If you are installing an HPL countertop there is no need to include plywood under the countertops because the material is very stable. 

If you are installing an engineered stone quartz countertop, you will want to have plywood under your counters for stability and support. 

Engineered stone is more fragile than HPL and will not be able to fully stand up to certain conditions like pressure, heat from a stovetop, etc.

So essentially, the type of quartz countertop you’re going to install will determine whether or not you need plywood under quartz countertops.

3. The Thickness Of The Quartz Countertop

The thickness of the quartz countertop that you choose to install is another factor. Typically, engineered stone can be anywhere from .75 inches to up to an inch thick. 

If you are installing a thicker countertop, it is important that the plywood be at least one-half inch thick. 

Thicker countertops are more stable and will be able to handle most things without buckling or breaking, but you still need to make sure that your plywood is thick enough and of high enough quality so it can support the weight.

You will also need thicker plywood if you are installing an HPL quartz countertop because the material is thicker than engineered stones.

So once again, your choice of thickness will influence the thickness of plywood you need for your countertops.

4. The Type Of Plywood You Use

Another factor that you need to consider is the type of plywood that you are using. 

Since some types of wood warp over time, you need to make sure that you use plywood that is not going to warp and cause your counters and cabinets to start buckling.

If you’re using plywood as the backer board for your countertops, make sure it’s something like MDF or particleboard. 

It’s very important that you begin with strong, durable plywood. Do not use regular wood because it can be too thin and will warp over time. 

5. The Thickness Of The Plywood

It is very important that you use plywood of a suitable thickness. You’ll want to make sure the wood isn’t too thin or too thick. 

Shorter-term countertops are usually about an inch thick, so you want to make sure that your plywood is at least half an inch thick. 

If you are installing a countertop that’s longer-term, then the plywood needs to be at least an inch thick.

So once again, the thickness of your plywood depends on how long-term you want to install your countertop for.

You’ll want to make sure that your plywood is at least .42 inches thick for general case scenarios, but thicker will be better if possible. 

If you’re using plywood that is less than .42 inches thick, it will probably not be a good option for most countertops.

6. Absorb Pressure And Prevent Cracks

The most obvious reason to use plywood under quartz is that it absorbs pressure and prevents cracks. 

Most engineered stone countertops are made from quartz, which is generally very strong. But if you want to put your mind to rest and clear all doubts, put plywood under the countertops. 

This is because, as we all know, putting too much weight even though it might not break the quartz countertop can put too much pressure on the plywood, thus causing cracks. 

So even though it might be expensive to use thin sheets of plywood for your countertops, it is one of the most important factors if you want to avoid cracks in your countertop.

So essentially, all I’m saying is, plywood can also help prevent cracking in the future; even though generally engineered stone is strong, it can crack or break if under too much pressure. 

7. If You Would Have Appliances Installed

If you will be installing appliances such as dishwashers, washing machines, and other appliances that cause vibration during their use, you might want to ask your fabricator or contractor to install plywood underneath your quartz stone.

In this case, the plywood installation will be able to absorb the vibration and pressure that will be transferred through the countertops.

These kinds of appliances are usually installed on plywood because it is very stable, but if the plywood is not installed under quartz countertops, any movement or vibration can cause cracks in your stone.

8. Plywood As Extra Support For Sink Areas

Another reason why plywood may be used under quartz countertops is its support for sink areas. One of the weakest areas when it comes to countertops, in general, are the parts around the sinks.

For this reason, your contractor may ask you to have plywood under the countertop around the sink area.

The extra support will help keep your countertop from bowing and it will help prevent sink areas from cracking over time.

The degree of support that is needed for the sink area will depend on its location. If you have a larger sink area, your contractor might suggest adding additional plywood underneath.

So essentially for the sink areas, plywood is used as extra support to prevent cracks and bowing.

Why Not Use Plywood Under Quartz Countertops? 

Plywood is not always the best choice under quartz countertops because it’s not as durable as other products. 

Plywood can be very thin, which makes it easy for installers to work with but also means that it’s less durable than other options. 

Over time, plywood can warp or split under the stress of daily use and exposure to water. 

Homeowners should consider more durable options, such as plywood that is made with marine-grade glue or even solid surface countertops. 

Marine-grade plywood is made to withstand exposure to water, which can be especially important for homeowners who are concerned about leaks or spills.

Solid surface countertops are similar to laminate in that they can be manufactured from a variety of materials, including engineered stone. 

However, they are much more durable and can be used for both countertops and as a backsplash.

Countertop Care & Tips

Kobby

Hi! I’m Kobby, one of the co-owners of favoredstoneguides.com and the newest house owner in town. I’m a huge fan of most things natural. Over here on this site, I'm happy to share all the exciting hacks, tricks, and tips I have learned and continue to learn each day about taking care of natural stones.

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