What is the required overlap for poly underlayment seams when installed under a concrete slab?

What is the required overlap for poly underlayment seams when installed under a concrete slab?

• A. 2 inches
• B. 4 inches
• C. 6 inches
• D. 8 inches

Answer: (C)

The correct overlap for poly underlayment seams when installed under a concrete slab is 6 inches. This requirement is crucial because it helps ensure a proper seal and maintains the moisture barrier's integrity. When the seams overlap by this distance, it mitigates the risk of moisture seeping through the seams, potentially causing issues like mold growth or deterioration of the slab over time. This overlap also allows for some movement and settling of the concrete without compromising the effectiveness of the underlayment. Proper installation practices, including the correct overlap, contribute to the longevity and performance of the flooring system above the slab.

The correct overlap for poly underlayment seams when installed under a concrete slab is 6 inches. This requirement is crucial because it helps ensure a proper seal and maintains the moisture barrier's integrity. When the seams overlap by this distance, it mitigates the risk of moisture seeping through the seams, potentially causing issues like mold growth or deterioration of the slab over time. This overlap also allows for some movement and settling of the concrete without compromising the effectiveness of the underlayment. Proper installation practices, including the correct overlap, contribute to the longevity and performance of the flooring system above the slab.