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I will be embarking soon on a remodel of a 1908 builder bungalow in Portland, OR. The project involves an attic conversion – with the addition of two shed dormers – and reroofing the remainder of the 7:12 pitch roof. I am working with the owner to determine whether to use comp. shingles or metal roofing (standing seam or coorugated). Does anyone have familiarity with metal vs. shingles, pro and con? The primary concerns/issues are cost, expected service life, & ease of installation / constructability. We’d also like to know how these options compare from a “green” standpoint.
Are there other options we should consider?
Note that the existing roof is a simple front-to-back gable, with only a few vent penetrations and one 8-10″ penetration at a s. steel chimney. The dormers ideally would have only a 2:12 pitch (to allow more headroom inside), however I understand this may present a problem with some (most?) roofing materials.
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Mike,
Local vernacular should be considered, as well as what roofing was commonly used on that style of house. Metal might work, but I'm thinking something else may be better. Portland, I'm guessing, is probably not the world's best location for cedar, maybe that's why you didn't ask about it, but here in the midwest it would be a good choice.
If you need to ask, then standing seam is out, since it is not generally a diy roof. You need tools and experience. Corrugated ag style roofing is somewhat easier, but still tricky, especially in flashing. Asphalt is easy for this job, maybe you can find some shingles that have a style you prefer.
As far as useful life vs. cost goes, it's hard to beat metal. It lasts a long time.
The "green" issue--these are bad things, environmentally, but everyone's got to make a choice. Obviously cedar doesn't take much in pollution to produce, but it is an environmental concern in itself because the best shingles come from heartwood of older trees. How about slate?
Good luck,
MD
*Hi Mike and MD,Looks like i should log in on this one.Good local suppliers are available for metal roofing here that's for sure. I agree with MD that dormer valleys, chimneys, penetraions, etc, do present a challenge with metal roofing. Your roof is walkable with comp but not metal, that changes alot of things too. Good quality comp (not 3-tab) would be my choice.I'm doing a 12" ziplock standing seam storefront awning roof in downtown Hood River right now. My material cost is close to $1 per sq', compared to the $.50 per sq' 25 year laminated comp i put up on my house last week.I purchase metal roofing from North American Metals in Hillsboro, comp i usually get from Dealers Supply in the SE warehouse district.joe d
*b TVMDCGood points, MD and Joe. The only problem with comp is on the 2:12 slope on the dormers. (Not pitch, see thread on collar ties and slope vs. pitch.)2:12 is really a little low unless you first apply something like smooth modified bitumen which will self-seal your shingle nails.
*yep, 2 is low. forgot to mention that. 3 in 12 is considered minimum for the metal I've used, but on a small to medium dormer it may be okay. Good idea about the bitumen Bill.
*In the past i used double #15 felt for 2 through >4/12. Nowadays i'd use OC ice/water shield and probably single felt. What are you guys using for 2/12 comp underlayment?Pretty sure you can use the 12" standing seam ziplock down to 2/12, maybe even less.joe d
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Many thanks for your comments and the links. I had planned on using a peel and stick membrane (Blue skin, 40 mil) over the sheathing on the 2:12 slope at the dormers (no felt) before the shingles go on. (What purpose does the single felt layer over the membrane serve?)
I do have a concern with the membrane though, regarding possible condensation problems with a "reverse side" vapor barrier, on top of the sheathing. So I'm not quite certain that's the way to go.
Anyone with recommendations on the "best" asphalt shingle (25 year life min., acceptable on in. slope...)?
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I will be embarking soon on a remodel of a 1908 builder bungalow in Portland, OR. The project involves an attic conversion - with the addition of two shed dormers - and reroofing the remainder of the 7:12 pitch roof. I am working with the owner to determine whether to use comp. shingles or metal roofing (standing seam or coorugated). Does anyone have familiarity with metal vs. shingles, pro and con? The primary concerns/issues are cost, expected service life, & ease of installation / constructability. We'd also like to know how these options compare from a "green" standpoint.
Are there other options we should consider?
Note that the existing roof is a simple front-to-back gable, with only a few vent penetrations and one 8-10" penetration at a s. steel chimney. The dormers ideally would have only a 2:12 pitch (to allow more headroom inside), however I understand this may present a problem with some (most?) roofing materials.
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asphalt... my fav is Certainteed's ((Hatteras))
got some great colors... 40 year life.. 8 inch exposure and a 9inch tab ...good looking roof..rated for 110 MPH....the 8x9 looks like slate....
b but hey, whadda i no ?