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TOPIC: Research/Data

I have a Cistern

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I am considering a metal roof over my 20 year old shingles that are starting to curl on the North side. Our sole source of water is from the roof, rainwater ino an 8000 gallon cistern. Is water from a metal roof safe to drink after filtering and a UV light which is our present method? Which is best for this, steel or aluminum? Is there official data available, or a guarantee of potability?
Guest User

4/19/2004
If your rainwater has been acceptable running off asphalt shingles then it will be just fine off a metal roof. Coatings of today do not contain lead as in the old days and frankly the polution that comes with the rain is what one needs to be concerned about. As a manufacturer, we have our rainwater off our products tested for potability however we can not recommend it given the liability issue of today. I can tell you that we have a lot of roofs in the Caribbean that collect the water and there is no problem. Both steel and aluminum are great and each has their own benefits. Remeber to choose a good paint or granular coating.
Allan Reid
Dura-Loc Roofing Systems, Inc.

4/20/2004
Hi, Allan, Can you provide the reports that are produced in your potability studies that you speak of in your response? I, too, will be constructing a residential structure in central America and would like to know what metal surface provides the best, longest lasting and healthiest option for rain catchment. I look forward to hearing from you. Thanks, Dave
Guest User

5/17/2004
Sorry Dave but with the legal system of today our lawyers have advised us not to hand our our testing as the moment we say the water is potable, then we are taking responsibility for it and as we have no control over polution and the type of storage tank it is somewhat understandable. If you are worried about paints then I would use unpainted Galvalume which I believe should give off only trace amounts of zinc over time. I would contact BIEC the owner of the patent or NAMZAC their association and try them.
Allan Reid
Dura-Loc Roofing Systems, Inc.

5/18/2004
Do you have any information on the paints used on metal roofing? Many are PVDF based, and seem to have high resistance to salt, acids, etc and are very stable. Has anyone done any potablility tests or certifications on these materials? Also, how would you rate a metal roof to a cedar shingle roof. It would seem that cedar shingles are treated with preservatives and require periodic treatments to maintain the material. Leaching of the woodpreservative into the water system from this source might be a concern and it seems that metal would not have this problem.
Guest User

5/25/2004
I again have no doubt that water from residentail metal roofing is potable if it starts out potable and there is nothing on the roof metal in between. I would be most concerned over the polution sources upwind such as coal fired power plants than I would be over the paint. I do believe that once you choose a system, that if you contact the coating manufacturer, they will be able to provide you with some sort of comforting letter that the lawyers have cleared. As to the other roofing materials that are not inert such as wood and asphalt, yes you will get more contaminants and metal as an inert material does not have the same issues.
Allan Reid
Dura-Loc Roofing Systems, Inc.

5/25/2004