Why Do People Add Plywood Under Their Countertops, And Do You Need To Do It?

Man adds plywood countertop base

Installing countertops inside your home is no simple feat. Visual aesthetics aside, there are several preparations you have to account for, especially if you opt for thicker, higher-quality counters. While a heavier countertop usually makes for a more durable substance, this strength could be nullified if the slabs don’t have the appropriate substrate supporting their weight. This paves the way for expensive issues waiting to happen in the future. Adding plywood underneath the various types of stone countertops homeowners should know about is often a necessary step in the installation process. It offers individual slabs the support they need to prevent cracking and other damage.

Due to their weight, countertops typically exert a lot of pressure, with some of the heaviest materials on the market weighing roughly 20 pounds per square foot or 700 to 1,200 pounds per slab. Kitchen cabinets can help alleviate some of this pressure by holding up to 600 pounds when properly installed. However, countertop overhang and other factors affect how much extra support counters need to remain centered and secure.

Plywood is a great underlayment option for homeowners since the surface is durable, affordable, and can offer aesthetic appeal without distracting too much from the counters themselves. Give your countertops the reinforcements to protect your home and those inside it. Here’s more on the benefits of adding plywood underneath your kitchen or bathroom countertops and how to determine if this supplementary task is necessary for your next countertop project.

Plywood Underlayment Prolongs The Life Of Stone Counters

Stacked sheets of plywood

Substrates like plywood allow countertops to remain durable indefinitely, one of the qualities homeowners admire most about natural and engineered stone counters. Quartz countertops should last a minimum of 10 to 15 years, and granite countertops can last a century or longer if installed correctly and maintained properly. However, cracks, inevitably caused by a lack of support and poor maintenance habits, can create safety issues in the home and ultimately reduce a countertop’s lifespan.

While smaller, surface-level cracks are easily fixable using a clear resin or epoxy, larger cracks from stress require professional attention and can be costly to repair. Such stress can also cause your countertops to sag downward if not properly reinforced. This often leads to breakage and the need to replace your countertops entirely.

The thickness of your counters can impact how susceptible they are to such damage. Countertops are available in various thickness levels, but stone options are commonly cut into 2- and 3-centimeter slabs. Thinner countertops are the most fragile, meaning they require the most added support from some sort of base to stay sturdy and intact. Full coverage isn’t always needed for countertops measuring 3 centimeters or thicker, but consult a professional before going without reinforcements.

Is Adding Reinforcements To Your Counters Necessary?

Man installing new countertops

Relatively thin natural stone countertops are most often considered the largest beneficiaries of reinforcements. But, in reality, most countertops would fare well with supplementary support, regardless of thickness or weight. Countertop overhang, or the length your counters extend past your kitchen’s cabinetry, greatly contributes to this need for additional reinforcement. A 1.5-inch overhang is considered standard for kitchen countertops, but some areas of your kitchen call for a much larger overhang, like an island with bar-style seating.

The amount of overhang a countertop can sustain without extra bolstering often depends on the countertop you install. Generally, any overhang greater than 6 inches will need an appropriate substrate, brackets, corbels, or support strips to help stabilize the weight of the counter’s edge. However, this may vary from case to case. Specific countertop sections, like bar tops and the area directly above your dishwasher, will almost always require added support.

With stone countertops, there are many types of plywood underlayments, each varying in strength and ability to withstand external forces. Choosing a form of plywood that resists moisture is highly recommended since residential countertops are often installed in spaces that regularly come into contact with water. Marine and exterior plywood are fairly moisture-resistant, making them ideal when paired with countertops installed inside kitchens and bathrooms.

Read the original article on House Digest