What should be done to prevent water from entering roofs with intersecting surfaces?

The chosen answer emphasizes the importance of installing proper flashing and underlayment to effectively prevent water from entering roofs with intersecting surfaces. Flashing is a critical component in roofing systems, as it directs water away from joints and seams where different roof planes meet. This is particularly vital at areas such as valleys, eaves, and around protrusions like chimneys or vents, which are often susceptible to leaks due to their unique angles and structural complexities.

Underlayment also plays a significant role by providing an additional layer of protection against water infiltration, covering the roof deck before the shingles or other roofing materials are applied. When both flashing and underlayment are installed properly, they work together to create a robust barrier against moisture, ensuring that water is directed off the roof rather than allowed to pool or seep into the underlying materials.

While utilizing impermeable membranes, ensuring proper slope, and regular maintenance are all beneficial to overall roofing performance, they do not specifically address the critical functionality of flashing and underlayment in managing water at intersection points. Membranes can be helpful in certain scenarios, but without effective flashing and underlayment, the risk of water intrusion remains higher, particularly at vulnerable junctures in the roof structure. Regular maintenance is also essential,