Installing new countertops can transform the look and feel of your kitchen or bathroom. Quartz countertops, in particular, are a popular choice thanks to their durability, stain resistance, and wide range of colors and patterns. However, properly installing quartz countertops is key to ensuring they last. So, do you need to put plywood under quartz countertops?
Overview: Do Quartz Countertops Need Plywood Underlayment?
The short answer is yes, installing plywood underlayment prior to quartz countertop installation is recommended. Here’s a quick overview:
- Plywood helps provide a smooth, stable surface for quartz countertop installation.
- It compensates for any minor imperfections or unevenness in the cabinet base.
- Plywood underlayment helps reduce the risk of cracking or damage to quartz countertops once installed.
- Most quartz countertop manufacturers and installers recommend installing plywood prior to quartz.
- The plywood also provides added structural support for the heavy quartz material.
While not necessarily required, plywood underlayment is strongly advised for a smooth quartz installation. Keep reading for more details!
Providing a Smooth Base
Quartz slabs are installed over your existing cabinets and need a perfectly smooth and level surface for proper support. Small dips, bumps, or uneven spots in the cabinet base can transfer to the countertop surface after installation.
Plywood helps compensate for any minor imperfections so the quartz has a flawless base:
- Creates a smooth, seamless look for installed countertops.
- Avoids uneven spots or rough areas in the finished quartz surface.
- Allows quartz to be securely fastened and adhere properly to the plywood sub-surface.
The plywood underlayment acts as a buffer and provides the ideal flat, stable foundation for a beautiful quartz countertop installation.
Preventing Cracks and Damage
In addition to providing a smooth base, plywood also helps add strength and durability to your quartz countertops.
The sturdy plywood reinforces the countertop area and helps prevent:
- Cracking, chipping, or breaking of the quartz material once installed.
- Damage from impact or heavy objects placed on the countertops.
- Cracks from settling or shifts in the cabinet base over time.
The plywood evenly distributes weight and pressure across the countertop surface area. This added structural support helps quartz resist damage, last longer, and reduces the need for repairs down the road.
Manufacturer Recommendations
Most major quartz countertop brands like Caesarstone, Cambria, and Silestone recommend installing over plywood underlayment.
The plywood provides the right amount of stability and support for their quartz products to adhere and perform properly over many years of use.
Always check your specific quartz manufacturer recommendations, as some may suggest a minimum plywood thickness or have additional installation requirements. Most recommend 3/4” thick, high-quality plywood at a minimum.
Following their guidelines helps ensure your quartz countertops stay beautiful for decades and allows you to maintain the product warranty.
Structural Reinforcement
Don’t underestimate the weight of a quartz countertop! A typical quartz slab can weigh 100 pounds or more per square foot.
Resting thousands of pounds of quartz directly on cabinets could lead to:
- Sagging shelves
- Misalignment of doors/drawers
- Cabinet structures becoming loose or unstable over time
The plywood adds an extra structural layer and reinforces the cabinets to comfortably bear the load of the quartz slabs. This also allows for safer transport and installation of the heavy material.
Installation Best Practices
If you’re ready to install new quartz countertops, be sure to follow these best practices:
- Choose high-quality, 3/4” thick plywood as the underlayment for durability and strength.
- Measure precisely and cut the plywood to fit your cabinets and layout. Leave a 1/8” gap between plywood sheets.
- Secure plywood to cabinets using construction adhesive and screws into the cabinet frame.
- Fill seams between plywood sheets with adhesive to create an even surface.
- Sand any rough edges for a completely smooth plywood layer prior to quartz install.
Following these steps will provide the ideal underlayment for gorgeous, long-lasting quartz countertops that you’ll love enjoying for years to come!
Frequently Asked Questions
Should I use anything besides plywood under quartz?
Plywood is the preferred choice. Materials like MDF or particle board are not recommended as they lack the strength and durability plywood provides.
What thickness of plywood should I use?
3/4” thick plywood is the most common recommendation. Go with high-quality, sanded plywood for best results.
Do I need to secure the plywood to the cabinets?
Yes, use construction adhesive and screws to firmly secure the plywood to the cabinet frame for stability.
What about gaps between plywood sheets?
Fill any seams with adhesive to create a smooth surface. The plywood should form one continuous layer.
Can I install quartz directly over existing laminate or tile countertops?
It is not recommended. You should remove old countertops completely and install plywood underlayment for quartz.
Conclusion
Installing plywood prior to quartz countertops may add a small extra step, but it’s well worth it. The plywood creates the ideal sub-surface for a beautiful, damage-resistant quartz installation that will last for many years. Be sure to use high quality, thick plywood cut precisely to size. Secure it firmly to the cabinets below. Following these best practices for plywood underlayment will set up your quartz countertops for long-term durability and satisfaction.