Assessing Wind-Damaged Masonite Shingles

Masonite shingles, aka Woodruff shingles, are wood composite simulated shake shingles that were popular in the mid-1980s to mid-1990s. Given these shingles are no longer manufactured, finding shingles to perform repairs to wind damaged roofs are difficult and in many cases a single missing shingle can trigger an entire roof replacement. The field shingles are less likely to be removed by wind; however, ridge cap shingles are fairly susceptible.

This paper reports on destructive testing performed on 17 year old masonite ridge-cap shingles. The testing utilized a force meter to remove both well secured, and not sowell secured, masonite shingles in order to gain an understanding of the forces required to remove the ridge cap shingles. Further, the withdrawal capacity of each roofing staple was determined from the test data and compared to values calculated from the National Design Specification for Wood Construction. The uplift force
results were also translated to an equivalent uplift pressure and compared to the uplift pressures generated by winds on traditional residential roof configurations as calculated with ASCE-7 – Minimum Design Loads for Buildings and Other Structures in an effort to correlate required wind speeds to remove masonite ridge cap shingles.