Case Study: Cedar Shake Roof Inspection

Executive Summary

Steep roofs constructed of fragile roofing materials pose a challenge for thorough inspections. To fulfill the scope of work for this project, Donan utilized a multirotor UAV, the DJI Phantom, to capture the data necessary to determine the cause of damage to a residential, cedar-shake roof.

Background:

On March 18, 2013, severe storms producing high winds and hail caused widespread property damage throughout portions of Georgia and other states. Although the National Weather Service did not report hail in the general vicinity, the property owners and their contractor believed the 11-year-old, cedar shake roof sustained hail and wind damages from these storms. In order to reach a determination, Donan’s forensic engineer needed to obtain observations that could clearly show whether the shingles contained identifiable marks that cracked the wood and whether any wood shakes had been partially or fully dislodged by wind.

Challenges

Several attributes of this roof and property posed challenges to conducting a thorough investigation into the cause of damage. Cedar shake roofs are easily damaged by foot traffic and should avoid being walked on; upper portions of the shakes were already damaged due to human foot traffic during prior inspections. In addition to the fragile roofing material, the roof’s steep slope required a lift or crane to inspect, adding time and cost. Finally, the grade of the yard and the property’s close proximity to a neighboring residence made it difficult to accommodate either a lift or crane.

UAV Application:

The multirotor UAV captured high definition videos and approximately 200 photos of the property. The videos and photos were reviewed onsite to ensure all the necessary data was collected. Donan’s forensic engineer was able to determine the cause of roof damage by studying the high-definition imagery captured by the UAV. The video and photos provided more extensive visual observation of hard-to reach areas on the roof than what would have been possible from a limited ladder-top only study. In addition to a successful investigation, utilizing the UAV for this project saved the rental and operator costs associated with a lift or crane, as well as shortened the turnaround time.

UAV APPLICATION:

Steep, cedar shake roof inspection

LOSS DESCRIPTION:

Determine the cause of damage to the cedar shake roof covering

HARDWARE:

Multirotor UAV

OUTPUT:

High-definition photos and video taken from UAV