Tar and Gravel
Tar and Gravel is New Mexico’s old standby, some even call it “traditional.” It is the cheapest roofing option, and homeowners get what they pay for. Tar and tar paper provide the roof seal, and gravel, in theory, acts as a UV barrier.
Realistically, the gravel prevents proper maintenance, by hiding any problem areas from a visual inspection. Meanwhile, the vertical areas along parapets, skylights and other exposed areas cannot be protected from the UV exposure, which leads to premature aging and eventual roof failure.
Local inspections and research prove that all areas of petroleum based roofing materials exposed to the New Mexican sun & climate begin cracking within 12 months. This includes canales, parapets and all penetrations (skylights, vents, ductwork, etc.).
Water will always find the path of least resistance. Sometimes out your canales; sometimes that’s through the cracks in your tar. Cracks of any size, even paper thin, allow water to penetrate a roofing system potentially causing serious interior damage. This is especially true if a crack is located under pond, allowing the pond to drain through the crack, rather than evaporating naturally. Cracking tar can also occur under your gravel, unseen. In the roofing industry, this is referred to as “alligatoring”, because the cracks open so wide, a pattern resembling an alligator’s back develops.