Inspectors should take which action regarding the fastening of asphalt shingle roofs?

When it comes to inspecting asphalt shingle roofs, the correct approach is to disclaim proper fastening. This is because, as home inspectors, the responsibility lies in assessing the visible condition of the roof without conducting invasive tests or removing shingles to determine the specifics of the fastening. Shingle fastening is often below the surface and not readily observable during a standard inspection.

Disclaiming proper fastening allows the inspector to indicate that while the roof may appear to be in good condition, the quality of the fastening methods used in the installation is not verifiable without further examination. This protects the inspector from liability related to the roof's performance and emphasizes the importance of proper installation practices for long-term durability and weather resistance.

Endorsing installation or reporting on quality could imply a level of endorsement or guarantee that goes beyond what an inspector can assert based purely on a visual inspection. Recommending upgrades could be considered if there was a clear deficiency, but that generally would not apply strictly to the fastening method unless there were observable issues related to it. Therefore, disclaiming proper fastening is the most appropriate action in this context.