How should hips and ridges be treated when applying underlayment?

When applying underlayment, hips and ridges should be treated in a manner that ensures proper water drainage and protects the roof structure. The correct approach involves allowing the underlayment to lap over the hips and ridges by at least 6 inches on each side. This overlap is critical because it enhances the waterproofing of these vulnerable areas, which are prone to water infiltration due to their design.

By ensuring that the underlayment extends beyond the hips and ridges, any water that runs down the slope is effectively diverted away from the joints, minimizing the risk of leaks. This helps in maintaining the integrity of the roofing system, particularly during heavy rain or snowmelt. Other methods, such as leaving them uncovered or cutting the underlayment flush, would compromise protection and leave these critical areas susceptible to moisture infiltration. Sealing with caulk is not a standard practice for underlayment application in these areas, as it can create a false sense of security without addressing the necessary physical barriers for water management.