How green is my roof?

September 8, 2008 9:58 PM

What are the best options for replacing our asphalt shingle roof with something equally long-lasting but greener?

We need to put a new roof on our house. The default option is asphalt shingles (replacing the current ones with new ones). I'd love to have something slightly greener or less petroleum based if possible. The roofing company is willing to install other roof types if we choose what we want.

Standing seam metal roofing (my preference) has already been vetoed as too expensive. So we're looking for something greener than asphalt shingles, less expensive than standing seam, and no heavier than asphalt (no tiles or slate). Longevity is also an important criteria for us - a 30-year or better guarantee.

This is for an Edwardian era building in San Francisco, CA (i.e. no snow or ice, lots of wind and rain) with a standard peaked roof. Most houses in the neighborhood have some variety of asphalt shingles. We're interested in potentially putting solar panels on at some point in the future, but probably can't afford both a new roof and solar panels, and the new roof comes first.

So, what are my options? In particular, if you have installed something other than asphalt shingles, what did you use and why? Are you happy with it? How did the cost compare to asphalt? Has anyone out there used the recycled rubber shingles?

posted by gingerbeer to home & garden (12 comments total)

Cedar shake shingles. They are very attractive and made from a renewable resource that is increasing in abundance. This picture sort of shows how they look on my house. They come in different grades/thicknesses - mine has a 25-year warranty and it is supposedly middle of the road.
posted by Ostara at 11:14 PM on September 8, 2008

Stone, slate, copper, adobe tile?
posted by rokusan at 3:44 AM on September 9, 2008

They're pretty expensive, so might not be an option for you, but eco-shakes are pretty cool, have a 50 year warranty, and look pretty sharp IMO. The City of Tulsa, OK has used these on some public buildings, and they have held up very well for the past few years.
posted by Shohn at 5:46 AM on September 9, 2008

You probably won't find anything as economical as asphalt shingles so expect to pay a higher amount for something else. Other alternatives are steel tiles.
posted by JJ86 at 5:56 AM on September 9, 2008

I recently had my house re-roofed with impact-resistant shingles—we get a lot of hail around here. These are basically made out of rubber (they look exactly like asphalt shingles though). The ones we used are rated for 50 years. I have no idea what their environmental footprint is, but it's something you could look into. They were a good deal more expensive than asphalt shingles, but probably cheaper than every other option.

I have heard of cementitious tiles that are quite a bit lighter than traditional clay tiles, but would probably still be on the heavy and expensive side.
posted by adamrice at 6:04 AM on September 9, 2008

Steel shingles.
posted by electroboy at 6:38 AM on September 9, 2008

Steel is real, but oh my, have you ever been inside a steel roofed building during a storm. It's loud. I would go with turf.
posted by caddis at 6:56 AM on September 9, 2008

Who's to say that asphalt isn't green? I assume that the old shingles will go to be recycled, and end up in tarmac for roads. But new shingles which have a 30 year or better guarantee seem to be a good use of materials. Shingles with a fiberglass base tend to be greener still, but not in a good way.
posted by Gungho at 8:02 AM on September 9, 2008

If I can come up with something else, I'll come back in and mention it, but if your roof framing is designed for the weight of asphalt shingles, there's not going to be a bunch of options for you other than asphalt and standing seam.

Cedar shake: It's renewable and light, sure, but also a tremendous fire hazard. I don't know how much of an issue that is in your area, but down here in SoCal, they're forbidden.

Stone/tile: Probably too heavy, unless you can find some sort of lightweight version, but the lightweight version will cost more. You might be able to get some sort of cementitious tile that will meet your weight limit, but still, it'll cost more than their standard roof tile. It will last much longer than asphalt, though -- on the order of 50 years. 30 years actually seems quite optimistic for an asphalt roof to me. Eagle has some lightweight tiles, and they've also recently developed a photovotaic tile that can be installed within the field of their standard tiles.

caddis, that green roof looks interesting, but I think you'd need a complete roof underneath the green tiles, because those don't look waterproof at all. It could probably be done with a simple built-up roof, but that's basically just a tar roof, and we're back to the problem with petroleum based products. Anyway, just by looking at the picture, the tiles don't look like they have an integrated water management system, and the standoff feet on their bottoms makes me think that they're designed to allow water to flow beneath them. So, those are basically nice things to put on top of your roof, not a roofing system in and of themselves.
posted by LionIndex at 8:08 AM on September 9, 2008

have you ever been inside a steel roofed building during a storm.

He'll still have the standard decking and builder's felt under the shingles, so noise shouldn't be a problem.

Green roofs generally only work on low slope or flat roofs and even then you basically need a complete EPDM roof under the green roof for watertightness.
posted by electroboy at 9:04 AM on September 9, 2008

Thanks, everyone. I grew up in a house with a metal roof, and actually quite like the sound. Tile, as I mentioned in my question, is too heavy, except for maybe those cementious tiles. Ditto for sod. The roof does need to be fireproof, so no cedar shakes, as nice as they look.

I'll look at those steel shingles, the rubber ones, and the eco-shakes. Anyone have more experience with those that they would like to share? Any challenges with installation?
posted by gingerbeer at 9:18 AM on September 9, 2008

It's pricey and complicated but I don't know if it gets much better than photovoltaic roof shingles. Replaces shingles, makes your whole roof a solar panel and lasts as long as shingles. Gotta have your house set for solar with the battery banks and all that, but hey, look at the example you set for the neighbors! Good for resale too, I bet.....
posted by Redhush at 2:20 PM on September 10, 2008