Replies

1. 
   Sphere | Mar 28, 2005 01:04am | #1

   If you insist on shingles, use Ice and water shield over the whole shebang, and cheat the exposeure of the shingles down to 4" to the weather. I have heard that helps alot, but no real first hand exp.

   I think your asking for trouble tho'.

    

   Spheramid Enterprises Architectural Woodworks

   "Sell your cleverness, Purchase Bewilderment"...Rumi

1. 
   Piffin | Mar 28, 2005 01:17am | #4

   That's the way I wopuld do it for a 2/12 to 3/12 but for lower slopes like this one, I would not even try it. I've been called to repair a dozen of these things where they tried every which way to do it and failed or had leaks within a few years.Problem partly is that the headlap creates a dimnension at the butts so while the overalll slope is 1.5/12, the surface slope for each individual shingle is slightly less than 1/12, depending onthe type and thickness of the shingle. So you can have water actually permanently puddling under the tabs. After ten years, even if the I&W keeps most of the water out of the house, the shingles are rotted and ice damaged with gree stuff gorwing in, under, and around... 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

1. 
   Sphere | Mar 28, 2005 01:23am | #5

   Yeppers..my 2 .5 " slope shed roof is less than 7? Y.O.

   Started to leak this winter way up by the top, Gotta tear off and do something different. Like I got nuthin else to do here..LOL 

   Spheramid Enterprises Architectural Woodworks

   "Sell your cleverness, Purchase Bewilderment"...Rumi

2. 
   panger | Mar 30, 2005 04:18am | #10

   I've got a similar question. I've just looked at a shed roof with less than a 1/12 pitch. The homeowner wants it waterproofed this year with the intent of building a deck right over top in the future. The roof comes right off the master bedroom garden doors. Will the polyglas work in this application and are there any other precautions I should take. We live in northern Manitoba so we get a lot of expansion and contraction.

1. 
   Piffin | Mar 30, 2005 05:36am | #11

   I use EPDM for that sort of application. A deck is an expensive thing to take a part if you have any leaks 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

2. 
   CHUCKYD | Mar 31, 2005 07:42am | #12

   Panger

   I agree that a single ply membrane would be good for your application. If you could get that roof slope down to 1/4" per foot (minimum slope per IBC), there are membranes available that could be used for the deck floor. I forget what they are, but they have been covered in FHB before. I raised a concern about spiked heels and smoldering cigarette butts, but the product has an impressive history. I believe the membrane material is something other than rubber or EPDM, but I don't recall what it is.

   If you can't reduce the slope, go ahead with any reliable membrane and place the deck floor in removable panels. Most manufacturers provide a slip sheet to place under loose laid supports which allow for differential movement without ripping the membrane. Sweets.com can lead you to most of the big boys in the business, but there are other similar catalog websites out there for that.

2. 
   Piffin | Mar 28, 2005 01:08am | #2

   Itis inappropriate to use any shingles on such a low slope. I&W shield will help, but I can gaurantee that it will not last for more than ten years.

   You say "The life of the shingles" but you should know that the manufacturere will not warrantee the life of the shingles when installed on that low slope. Not only will the slow drainage promote leaks, but will shorten the life of the shingles by keeping them wetter longer and holding ice.

   For low slope roofs you are better off geting a peel and stick membrane with the same coloured chips on surface and reinforcement as the shingles. Polyglas is what I use here. There are other brands.

    

    

   Welcome to the
   Taunton University of Knowledge FHB Campus at Breaktime.
    where ...
   Excellence is its own reward!

1. 
   Sphere | Mar 28, 2005 01:12am | #3

   Yeah,,,what you said. 

   Spheramid Enterprises Architectural Woodworks

   "Sell your cleverness, Purchase Bewilderment"...Rumi

1. 
   GCourter | Mar 31, 2005 05:24pm | #13

   yeah, what you said he said!

2. 
   user-47275 | Mar 28, 2005 02:48am | #6

   Thanks for the strong advice. I'll take a look at Polyglass.Regards,
   Steve Mann

1. 
   jimbotoo | Mar 28, 2005 07:33am | #7

   Since you're apparently in the design stage, is this low-slope roof really necessary?  Nothing in the way of materials takes the place of a good roof slope to prevent leaks.

   Alternatively, maybe the entire roof needs to be metal.  Just another idea.

1. 
   sarison | Mar 30, 2005 02:56am | #8

   I'm right now in the repair stages of a 3 1/2 year old owens corning , oakridge 30 on a 2 1/2"/12".  The same thing happens, water pools between courses, then runs out days later between shingle layers (the course above is dry, the course below is wet, draining from above).  I think I'm going to have to EPDM the whole thing as a warranty.  I've torn it off and used Grace on the entire roof (11/04) and the grace didnt adhere at the overhang because water is still flowing behind the drip edge.   The only other solution is to custom bend a tall drip that dumps into the gutter and Karnak the edge with grace over top.  This won't stop the mold issue  discussed earlier though.  I'm torn!?!?

3. 
   CHUCKYD | Mar 30, 2005 03:56am | #9

   You may want to check your building code for roof slopes. I agree with all the others that low slope shingles are not the answer. The suggestions for metal roofing are good ones for aesthetic applications, while the membrane roofs are ok for utilitarian applications. Some cautions for the metal roofs, though , are to get concealed fasteners, allow for expansion and contraction of the metal in the long direction, and properly close the bottom and top ends of the panels.