What is the process when laying poly underlayment under a concrete slab?

When laying poly underlayment under a concrete slab, it is important to ensure that the edges are overlapped properly to provide an effective moisture barrier. Overlapping the edges by 6 inches is a common industry standard that ensures a secure and continuous barrier against moisture migration from the ground below the slab. This overlap helps to prevent issues related to water infiltration, such as mold growth or slab deterioration, which can arise if gaps or seams are present in the moisture barrier. A 6-inch overlap strikes a balance between being substantial enough to secure the moisture barrier while also being manageable for installation, making it the recommended practice for this process.