The answer to 'why is my roof decking clogged gutters' is that clogged gutters can cause water to back up and seep into the roof decking. This can lead to rotting, mold growth, and structural damage over time. Clogged gutters prevent proper drainage, causing water to pool and eventually work its way into the roof system.
Common causes of clogged gutters include leaves, twigs, pine needles, and other debris that accumulate in the gutters. Symptoms may include water overflowing the gutters, sagging or pulling away from the roof, and visible signs of rot or mold on the roof decking or fascia. To fix the problem, you'll need to clear the gutters and potentially make repairs to the roof decking or other affected areas.