What Flexural Strength Does a Quartz Countertop Need to Have?

Quartz countertops are popular options for kitchen and bathroom remodeling projects thanks to their durability, low maintenance, and stylish appearance. When selecting a quartz countertop, an important consideration is the material’s flexural strength. Here is a detailed overview of the flexural strength requirements for quartz countertops and why this specification matters for performance and safety.

What is Flexural Strength for Countertops?

Flexural strength measures a material’s ability to resist breakage when subjected to a bending force. It indicates how much load a horizontal surface can withstand before it cracks or snaps.

For countertops, high flexural strength is essential to prevent damage during everyday use. Countertops must bear the weight of heavy objects without cracking or chipping. They also endure impacts from dropped items. Materials with low flexural strength can gradually weaken and fail over time.

Flexural strength is typically measured in megapascals (MPa). It is tested by placing a sample over two points and applying force from above until the sample breaks. The amount of force at failure divided by the sample width provides the flexural strength rating.

Quartz Countertop Flexural Strength Requirements

To provide durable performance, quartz countertops should have a flexural strength rating of at least 15 MPa. This minimum strength recommendation comes from the International Cast Polymer Association, which sets material standards for solid surface countertops like quartz.

However, not all quartz countertops are created equal. Flexural strength varies between different manufacturers and product lines. High-end quartz from leading brands typically tests in the 18 to 30 MPa range. A rating of 20 MPa or higher provides an extra assurance of durability.

Why Flexural Strength Matters for Quartz Countertops

There are several reasons why higher flexural strength translates into better performance for quartz countertops:

Withstands Impact

Quartz with higher flexural strength is less prone to chipping or cracking when subjected to sudden impacts. Dropping a heavy pot or pan is less likely to damage the surface. This improves durability and reduces the need for repairs.

Resists Bending

Stronger quartz can better handle the weight of people sitting or leaning on countertops without excessive bending. This allows for a thinner profile that saves on material costs.

Provides Support

Higher flexural strength allows quartz manufacturers to span greater distances between underlying supports. This enables long, seamless countertop runs without reinforced support beams.

Prevents Breakage

Over time, small flexes in a quartz countertop can cause material fatigue. A weaker surface is more prone to developing hairline cracks that turn into outright breaks. Stronger quartz is more resistant to this gradual failure.

Promotes Safety

Excessive bending or breakage poses a safety hazard for users. Flexural strength provides assurance that the quartz can bear typical loads without unexpected structural failures.

What Level of Flexural Strength is Recommended?

For optimal durability and safety, select a quartz countertop rated at 20 MPa or higher. This provides a large safety margin above the minimum requirement. Leading brands like Caesarstone, Cambria, and Silestone offer options at or above 20 MPa for premium resilience.

Avoid quartz rated below 15 MPa, as it offers inadequate strength for a horizontal surface. Also be wary of manufacturers that do not provide flexural strength specifications, as their products likely fall on the lower end.

Checking Flexural Strength Specifications

With an understanding of why flexural strength matters, check product datasheets to choose an appropriately strong quartz. This critical detail is often overlooked by consumers. Be sure to ask retailers for flexural strength ratings before purchase.

Higher-priced quartz typically offers stronger flexural performance. However, there are affordable options from quality brands that still provide adequate strength. With a suitable rating, you can have confidence that your beautiful new quartz countertop will withstand years of regular use.

Frequently Asked Questions About Quartz Countertop Flexural Strength

How is flexural strength tested for quartz?

Flexural strength testing involves placing a supported quartz sample over two points spaced 16 inches apart. Force is applied from above at a rate of 1.3 mm/minute until the sample fails. The maximum load at failure divided by sample width determines the MPa rating.

Does thicker quartz have higher flexural strength?

Not necessarily. Flexural strength depends on the quartz material composition, not thickness. Some thinner engineered quartz can have higher strength than thicker solid natural stone. Always check the MPa rating.

Does quartz strength decrease over time?

Quartz can exhibit slight decreases in flexural strength after prolonged UV exposure. However, quartz rated 20 MPa or higher when new provides ample strength margin to withstand many years of use without issues.

What household cleaners reduce quartz strength?

Harsh chemicals like oven cleaners or drain openers can damage and weaken quartz, reducing flexural strength over time. Mild soap and water is the recommended cleaning method.

How can I improve weak spots in my existing quartz?

For quartz lacking adequate flexural strength, reinforce suspected weak points underneath with added plywood support strips. This helps prevent cracking or breakage in problematic areas.


When selecting a durable and safe quartz countertop, flexural strength should be one of the key specifications considered. Look for ratings of at least 20 MPa from reputable manufacturers to ensure excellent impact resistance, bending allowances, and long-term performance. With strong quartz across your kitchen or bath, you can confidently enjoy the beauty of these low-maintenance engineered stone surfaces for years to come.