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I want to re-roof my home, but want to use a sustainable option. Is there a resource where I can compare different sustainable options and find the best choice for my budget and situation? I'm trying to avoid e-commerce portals.

Can anyone offer a comparative analysis of currently available materials?

  • This is almost... but not quite... a shopping question. I, too, would love a resource like that. But all I can come up with would be e-commerce stuff, which makes me think this is more shopping. Maybe a book? – Daniel Bingham Feb 6 '13 at 17:12
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    I'm hoping for a book or some sort of non-shopping online resource that talks about materials, their costs and pluses/minuses. – thatmiddleway Feb 6 '13 at 17:31
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    Maybe editing the the question so that it's more asking about the pros and cons of various materials? Heck you might not even need another resource, someone might be able to give you a comprehensive comparison in an answer here. – Daniel Bingham Feb 6 '13 at 17:33
  • To get a list of options your better off visiting the library than posting to SE. After getting info from more generalized sources come back and ask more specific question(s). – OCDtech Feb 21 '13 at 21:20
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I understand that this isn't a link to a complete reference, but it is a general list that might get you or others started.

The primary sustainable roofing systems I am aware of are:

  • Metal - These can be used to collect rainwater and many are coated in such a way that they do not contaminate your water. The roof can last 50 years, and even then, the metal can be recycled at the end of its life. Around here, it costs about $10/sqft installed [reference] and of the four listed here, the most easy to find a local contractor.
  • Green Roof - This often requires a rubber membrane (most often a synthetic) on top of which soil and plants are placed. This kind of roof adds a significant weight to your roof and so is often not possible in retrofits without reinforcing the load bearing walls. This type of roof is often claimed to reduce both heating and cooling costs due to its thermal mass, the evapotranspiration of the plants and a small increase to R-Value. Installed, a green roof can cost $15-$20 [reference], though many people do it themselves and about their only cost is in the rubber pond liner.
  • Thatching - This is often done with special grasses and can be quite tricky, though it is completely compostable and the only/most common system I have seen which could conceivably be grown and produced 100% locally and/or yourself. It seems to be more common in England and other parts of the world than the US, so I know less about it. Anyone else know more?
  • Wooden shingles - Honestly, I don't know much about this option. This site claims an installed cost of around $6/sqft. It would be interesting to know how much this would change if you tried to ensure local/sustainably sourced wood. This one could also probably be almost completely DIY, though I am not sure.
  • +1 nice answer! – THelper Apr 17 '13 at 8:34
  • Another (structural) benefit of metal roofs is that they're actually less heavy than most other alternatives, which can be good for the house underneath them. – Nate Apr 21 '13 at 10:44
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You may like to consider having a roof that reflects as much sunlight as possible back into space, thus increasing the earth's albedo. This probably means having a white roof, but I do remember hearing about special roof paints that are coloured but are designed to reflect as much infrared (heat) radiation as possible, which would be a partial (but likely expensive) compromise.

More information here.

  • +1 just for the curiosity factor. This is something I have heard for the first time... Project heat back into space. And you are considering this sustainable because it would revert global warming, at least, eh... partially? – Earthliŋ Feb 13 '13 at 3:00
  • It helps a little. The linked article has some figures. – Highly Irregular Feb 13 '13 at 4:05
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    Actually, I'd say that it helps a lot. It's only a little because not many people do it yet. Go out on a sunny day, and put your hand on black asphalt, and see how much heat a black surface absorbs. Many roofs are dark colors. Composite roofs get very hot (I've worked on them plenty), which is both bad for the warming problem, and degrades the materials (causing the roof to need replacing). US Energy Secretary Steven Chu, PhD., has specifically identified this as a high value-per-unit-cost remedy. – Nate Apr 21 '13 at 10:40
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I suspect a white roof made (at least partially) of recycled materials--and 100% recyclable or compostable materials--is your most sustainable option. It will greatly reduce the amount of heat your house absorbs in the summer, which will reduce the amount of energy you need to cool your home. During the useful life of a modern roof, the energy cost of heat absorbed from sunlight is probably a significant portion of the roof's environmental impact. This is especially important if you live in a hot, sunny climate, but even at 50 degrees N white roofs help more than they hurt. Metal roofs are less effective from this perspective than white roofs, but better than dark roofs. Of course, you could always add a white coating to a metal roof.

I don't know anything about sustainable white coatings for roofs, but it's something to look into for the comfort and energy efficiency benefits.

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    Metal roofs do come in white, or a very light colored silver color that's almost white, and has great albedo. – Nate Apr 21 '13 at 10:45

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