What type of material is applied over the upper portion of wood shakes after nailing each course?

The application of 30 lb roofing felt over wood shakes provides additional moisture protection and enhances the longevity of the roofing system. This heavier felt offers superior durability compared to lighter weights, making it a preferred choice in many roofing applications where increased resistance to water and weather conditions is essential.

Using 30 lb roofing felt helps to prevent water infiltration between the shakes, which is particularly important as the wood shakes themselves may allow some water penetration during heavy rains. This added layer aids in directing any moisture that gets beneath the shakes away from the underlying structures, thereby reducing the risk of rot and damage to the sheathing and framing.

Moreover, 30 lb felt is also more resistant to tearing and damage from the elements, making it a better long-term investment for roofing applications compared to lighter options. In situations where additional weight and durability are required, the choice of 30 lb roofing felt ensures that the roof remains both functional and reliable over time.