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A client of mine is looking to re-roof.

LWkARsfFd4 | Posted in Green Products and Materials on

She is interested in rainwater harvesting. She is concerned with the asphalt residue leatching out of the shingle roof and eventually ending up in her vegetable garden. Any ideas on other roofing material (other than the obvious metal, cedar shingle, synthetic) which would cost much more. Any organic shingles without asphalt?


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  1. Mike Eliason | | #1

    "of the five roofing materials tested, metal (specifically GalvalumeĀ®), concrete tile and cool roofs produce the highest harvested rainwater quality for indoor domestic use. The study also showed that rainwater from asphalt fiberglass shingle roofs and increasingly popular "green" roofs contain high levels of dissolved organic carbon (DOC). Although other potential pollutants can be significantly lower on green roofs (turbidity and aluminum), the high DOCs are significant where these roofs would be used for potable rainwater collection."

    i would avoid wood shingles.

  2. GBA Editor
    Martin Holladay | | #2

    If you are harvesting water from your roof, choose metal roofing.

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