• Single plies: Poor, inconsistent welds, improper fastener spacing, and unadhered base flashing.
• Hot bituminous: Inadequate temperature control of asphalt, poor interply integrity and dry laps.
• Torch-applied modifieds: Fire safety concerns, over/under torching and voids in seams.
• Steep slope: Improperly spaced decks, buckled plywood, no waterproofing underlayment installed in valleys, and improperly installed step flashings.
• Cold-applied roofs: Improper materials storage and seaming problems at the selvage edge and end laps.
• Roof decks/subtrates: Under-driven fasteners, incorrect attachment patterns, and loose or damaged insulation.

-http://www.rsimag.com – Mike Russo -

A common valley area shingling mistake made by many novice roofers and DIY homeowners.

Heavy rainfall flowing down the roof valley will catch the points of the asphalt shingles and run horizontally along the top edge and under the shingles. When the water finds a hole in the underlayment it will run into the attic and then the house. This shingle and all others that end with a point in the valley should be trimmed back from the waterline. Simply cut the shingle at a 45-90 degree angle a minimum of 2 inches back from the point.

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