Hurricane Wilma tore off the tabs of about 50 % of the 3 tab shingles on my 2.5 slope roof here in Miami. The roof is estimated to only be between 10 and 15 years old. I had been seeing washed off granules in the gutter and the grass around the house for years. I am appalled by the flimsiness of the 3-tab shingle and the premature failure of its tab adhesive.
I intended to replace the roof with Owens Corning Weatherguard HP 40 year, which I chose for its UL 2218, Class 4 impact rating wind resistance up to 130mph and its claim to use a very aggressive adhesive.
Now I am receiving mixed messages:
Pros on this forum reject all dimensional shingles for slopes less than 3 / 12.
Of the roofers who got on my roof to give me a quote 1 outright refused to use dimensionals, others would install it but claim it offers no benefit over the 3 tab.
Yet another claims not to have had any problem with installing dimensionals.
The manufacturer specifies 19 Ã¢â‚¬Å“ overlap on the felt underlayment on slopes between 2 and 4 and current Dade county code (supposedly the strictest in the land) allows it to be used if so installed. The old South Florida Building Code, of 1999 says: “dimensional shingles are limited to 3 Ã‚Â½: 12 slope (min.)”. When calling OC they claim Ã¢â‚¬â€œ surprise surprise - never to have heard of the problem.
Is what IÃ¢â‚¬â„¢m getting here a blend of hearsay, folklore, Ã¢â‚¬Å“thatÃ¢â‚¬â„¢s the way we always do itÃ¢â‚¬