Roofs for Natural Buildings

Dan Chiras has been involved in natural and alternative building since 1994 and lives in an off-grid passive solar/solar electric home in the foothills of the Rockies. His house is built from straw bales, rammed earth tires, and numerous green building materials and is powered entirely by wind and solar energy. Dan is author of The Natural House: A Complete Guide to Healthy, Energy-Efficient, Environmental Homes, published by Chelsea Green; and numerous articles on natural building and sustainable design, which have appeared in Mother Earth News, Natural Home, and The Last Straw. Dan embraces a comprehensive systems approach to building that offers a wide range of benefits to people, the planet, and our economy. He will field general questions on natural building and offers consultation on project design and construction, as well as lectures and workshops on various aspects of natural and sustainable design and construction.

Questions and Answers

Q: My husband and I are contemplating the possibility of buying a bit of land with an incredible view and would love to put up a "green" home. We are very financially tight AND the rancher that is selling off parcels is not a "tree hugger" (as the realtor put it) and therefore wants things to look conventional on the outside. I refuse to use asphalt shingles, and can't seem to get as much info. on roofing, in terms of something that would look fairly conventional. I know tile can be really expensive... Any thoughts about a roof that would go well with the outside of our home and be "green".

A: (Kelly) Green roofing material is somewhat hard to come by, especially for conventional looking houses. Such truly green materials as thatch would look out of place. Tiles or slate might be good choices, but as you say, they are expensive (so is thatch). I guess a reasonable compromise might be a metal roof, where the cost is less and it is fairly durable; much of the steel that is used these days is actually recycled.

Q: What sort of earth-friendly roofing do you recommend?

A: My favorite product is metal (steel) roofing. It lasts a long time. There are a number of other environmentally friendly shingles but I like metal roofing, if that works with your plans.

Q: I am chemically sensitive and we are need to have our roof re-shingled for the third time in a year due to poor construction on the first two tries. We now have a reputable roofer, but as I am chemically sensitive and on disability, I'd like to take all the necessary precautions. You mentioned that there "are low- and no-formaldehyde OSBs available on the market". Are there any sources for the same in plywood, which is what we had on our home originally? Also, would you know how much off-gassing might occur if we couldn't get the low-no wood? We have our attic air handler in the attic where the roof will be re-shingled.

A: I am not aware of any companies that manufacture low- or no-VOC plywood, only low- or no-VOC OSB. OSB makes a great roof decking, so I'd use that product. Both Weyerhauser and Louisiana Pacific offered low-VOC OSB a few years ago.  You can special order low-VOC from your local building materials outlets. The James M. Huber company makes a no VOC OSB. You may be able to order this from a local building materials supplier. If you can't get low- or no-VOC OSB or plywood, be sure that the product you buy is aired for a couple weeks in a dry place (for example, a garage or car port) before installation. Also, be sure the sheets are placed in such a way so that each one can is adequately aired. Just piling them in your garage won't work. You need to put spacers between each sheet so air circulates over and around the wood. Finally, you should seal the sheets with water soluble polyurethane before installation. That should protect you fairly well.

C: I may have a lead on some no-formaldehyde plywood. FW Honerkamp in  NYC has naf (no added formaldehyde) plywood and they say that phenol formaldehyde is used instead in the plywood glues which only off-gasses when it burns as opposed to the urea which off-gasses at room temps and above:

I did find a great sealant too from AFM. It's called Safe Seal. http://www.afmsafecoat.com/products/stains-sealers