*This article by INSTALL executive director David Gross was originally featured in Floor Covering News Magazine.

INSTALLments: A Series on the Challenges & Opportunities in the Floorcovering Trade 

When Specifying SPC, Thicker Is Not Always Better 

By David Gross, Executive Director of INSTALL Flooring

Valued for its rigid-core construction, dimensional stability, and ability to mimic the appearance of wood and stone, stone plastic composite (SPC) has become a mainstay in single-family and multi-family homes as well as light commercial spaces. For this material, thicker products, ranging from 6mm to 8mm or more, are often presumed to deliver better performance over a wider range of subfloor conditions. While this may hold in some cases, thicker is not always better, and thinner SPC products in the 4mm to 5mm range can often perform just as reliably when matched to the right conditions. For retailers and distributors, understanding where thicker SPC makes a meaningful difference, and where thinner works equally well, is critical for guiding customers in selecting optimal products for their projects.

Performance Realities of SPC Thickness 

Many flooring professionals and their clients equate added SPC millimeters with higher quality, but factors such as subfloor condition and daily use patterns must also be considered to avoid overestimating the impact of a thicker plank. To help flooring professionals identify the best fit for an application, the following are common assumptions about SPC thickness, along with insights on where they are accurate and where thinner SPC may be indicated. 

Subfloor condition
Thicker SPC does offer slightly greater tolerance for surface irregularities, but that benefit is often overstated. When applied over properly patched and leveled subfloors, thicker SPCs can help bridge small dips or high spots and control telegraphing. In practice, when subfloors are well-prepared and flat within tolerance, thinner SPCs perform just as reliably and often simplify transitions and height clearances. Regardless of thickness, proper subfloor preparation remains essential. Flatness, moisture control, and correct expansion spacing are critical to avoiding joint stress and locking-system issues. 

Underfoot feel
One of the most noticeable attributes of higher-thickness SPC is a more substantial foot feel. In high-traffic multi-unit or light commercial environments, where perceived quality can influence purchasing decisions, added mass can make the floor feel more stable and premium to occupants. Thicker profiles also offer greater resistance to point loads and rolling traffic. By contrast, in traditional single-family homes with moderate foot traffic, thinner SPC can deliver an acceptable level of underfoot comfort, as the perceived benefit of additional thickness may be minimal. 

Acoustics
In upper floors, condominiums, and multi-family housing, the added mass of thicker SPC is often desirable, as it helps dampen noise transfer between neighboring spaces. In single-family homes or in rooms with appropriate underlayment, however, thinner SPC products can achieve similar acoustic results. Ultimately, acoustic outcomes are driven more by underlayment selection, subfloor type, and overall room construction than by plank thickness alone. 

Appearance
Thickness also influences the perception of quality and visual stability. In open layouts or long runs, thicker profiles can contribute to a more consistent appearance by reducing visible joint movement under foot traffic. In smaller rooms or remodels with demanding transitions, thinner SPC can deliver the same finished look while minimizing height buildup in transition areas. As with other performance attributes, visual consistency depends heavily on subfloor flatness and installation precision—factors that thickness alone cannot overcome. 

There is no question that higher-thickness SPC offers real advantages in certain installation scenarios. At the same time, thinner profiles are often the more practical choice without sacrificing performance. Recognizing when thickness meaningfully contributes and when it is optional helps ensure SPC delivers the desired outcome without unnecessary cost or complexity.