low slope, stylish, and concealed fasteners?

Mary DeDanan
9/21/2011
I am building a tiny house. It's only 8' wide and 26' long. Shed roof w/ low slope, slightly less than 1:12 -- no dormers, no valleys, no protrusions, all very simple on purpose. Area has hot summers, mild winter temps but heavy winter rain and wind. Roofing it will be a DIY project with lots of help from very skilled builder friend. I want to use metal roofing for its fire resistance, longevity, and all that good stuff. But most of the material I can find for such a low slope is u-u-u-u-ugly -- your basic commercial ridged standing seam. The style does not appeal, although I want the durability of locking panels and concealed fasteners. I'm interested in Met-Tile panels, because it is a lot more in keeping with my tiny house's Japanese styling. Met-Tile's FAQs (http://www.met-tile.com/faq-res.html#12) say: "A minimum roof slope of 2-in-12 is recommended, though lower slopes are acceptable if the side laps are caulked." Is that trustworthy? From the drawings, Met-Tile panels have exposed fasteners, a drawback. Is there another metal roofing product a) suitable for low slope, b) looks stylish, like fake tile, or slate, or such, AND c) has concealed fasteners? I very much like the metal shingles now on the market, but specs say minimum pitch 3:12. Can I fudge that to 1:12, or do I risk disaster? I'm certainly willing to use extra goop or tape or foam or whatever it takes. Thanks!
Todd Miller
Classic Products, Inc.
9/21/2011
I would not use anything other than a mechanically seamed standing seam on a roof of that low of pitch.
Mary DeDanan
9/22/2011
Thanks, Todd. Appreciate your advice. Is there anything in standing seam panels that LOOKS better? I don't care for the modern, commercial aesthetic. I suppose if I must, I must. But when I'm spending that much money and effort, and will be living with it the rest of my life, I'd sure like to find a panel I liked.
Todd Miller
Classic Products, Inc.
9/23/2011
Thank Mary. I appeciate that. I think that choosing a color you like will be helpful. Also, in my opinon, narrower panels look better and more resdetial. Is there any opportunity to increase the roof pitch?
Mary DeDanan
9/24/2011
Afraid not. The low pitch was chosen for other reasons and is what it is. I'm still tempted by Met-Tile's promise that their panel would work on 1:12. But what do I know? Thanks!
Todd Miller
Classic Products, Inc.
9/24/2011
Met-Tile was recently purchased by McElroy Metals, which is an MRA member manuacturer. I would suggest contacting the gooid folks at McElory and seeking their input direct for your application.
Info @windowsonwashington.net
An informed customer is our best customer.
9/25/2011
I don't like the idea of exposed fasteners or relying on a caulk joint for proper water seal myself. You could always put ice and water or similar membrane across the entirety of the roof and hope that keeps the moisture that will most likely make it through the panels out of the home.
Mary DeDanan
9/27/2011
I spoke yesterday to a McElroy sales guy about the Met-tile panel and low slope, emailed him my specs, am waiting for his quote. He said on phone that I should use their special super-duper sticky underlayment, "that's the real roof, metal just protects that." He wasn't sure what happens when a screw penetrates the underlayment, perhaps it self-seals around the threads. Says to use their special mastic tape at the corrugation overlap and a "stitch screw" over that. Do you believe him? Should I? Suppose I should error on the side of caution, not style. Sigh. Hey, you metal roof manufacturers. I'm a real-life consumer, ready to purchase, but unable to find the style I want to fit the situation I have. There's an opportunity for someone.
Todd Miller
Classic Products, Inc.
9/27/2011
I have over my 30+ years seen numerous below-pitch installations of metal panels where the installer tried very substantial underlayments to guard against leaks ... and they all still eventually leak. I would not do it. I'm sorry.
Guest User
9/27/2011
That I believe. Nothing like the voice of experience. I take it that the standing seam panel is the exception to that?
Todd Miller
Classic Products, Inc.
9/28/2011
Yes, by "below pitch" I meant installations below what the manufacturer has tested and approved the product for. In the case of tile profile metal panels, usually 3:12 is the minimum pitch. Some mechanically seamed standing seams can be used down to 1/4:12 pitch.
Info @windowsonwashington.net
An informed customer is our best customer.
9/28/2011
+100 Do not, I repeat, do not rely on a peel and stick ice and water shield to be your water infiltration barrier. If the roof is not going to be the water barrier, why put it on top. Ice and water will break down and you will be left with a nice metal roof that leaks. Not a suitable option. Look into standing seam and one that mechanically locked together.
Guest User
5/20/2014
Amazed to find this thread! I'm working to source an appropriate metal roofing product for a very similar project. I'm building an 8.5 x 24 foot tiny house with a simple 1.5:12 pitch shed roof. The roof sloping in the long direction, so panels will need to be just over 24 ft in length. I would prefer NOT to use standing seam, mainly because I want to do the roofing installation myself. Can you recommend any hidden fastener or locking panel systems approved for slopes 1.5:12 or lower? I am fine using products designed for commercial/agricultural uses if they meet my needs. Thanks!
Info @windowsonwashington.net
An informed customer is our best customer.
5/21/2014
You can probably get a single ply membrane roof if a roll width that will allow you to use it in this application but this is a metal roof forum so I figured you were leaning that way. Where is the home going to be? Standing seam is your best bet here. A clip style lock should be fine.
Guest User
5/22/2014
Thanks Eric! One of our regional suppliers offers a hidden fastener system with locking seams, but it is only rated for a 2:12 slope: http://www.idealroofing.com/english_us/html/prod_hf.php?type=lw Could you recommend any specific clip style locking panel systems that would work for a 1.5:12 slope? Any specific product/supplier info would be much appreciated.
Info @windowsonwashington.net
An informed customer is our best customer.
5/23/2014
Any chance you can just add a bit of pitch to the home? Depending on where the home is located, they are probably more worried about snow at that pitch if we are talking about a straight run. See if you can add a tiny bit of pitch to the home as that will be better for convective cooling as well and you can solve all of your problems right there.

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