In single underlayment application, where should installation begin?

Starting the installation of single underlayment at the eave line is crucial because this approach ensures that water flows over the underlayment rather than under it. The eave, which is the lower edge of the roof that overhangs the walls, is the first line of defense against the elements. By beginning at this point, the underlayment can effectively direct any water runoff down the roof and prevent leaks into the underlying structure.

When the installation proceeds from the eave line upwards, it also allows for proper layering of the materials. Each subsequent layer can overlap the one below it, helping to create a watertight seal, which is essential for maintaining the integrity of the roof system. This method of installation is vital for ensuring that the underlayment functions as intended and provides optimal protection against water intrusion.