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Discussion Starter · #1 ·
I am going to be roofing a building that has some areas that are 2 in 12 pitch. I am going to be using comp shingles and double felt. Please share any tricks or tips for making this roof water tight.

Thanks

Dave
 

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Pro Slate Roofer
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To be honest, the shingles and double felt will work about as well as leaving just the plywood to fight the elements. About 6 months later, some of the plywood will be saturated. Within a year, the leaks will show inside and the plywood will be falling apart. Plan on redecking it then.

Or, you could look into SBS low slope. Match the roof color. Put down the nailable base sheet. Add one, or two inter-plies, then, the matching color granulated cap sheet.
Here's the tech stuff http://technicaldatabase.fsbp.com/downloadFile.ashx?fileId=[fid=1952|pid=808]

More http://www.mbtechnology.com/roofing-system-selection-guide/

More http://www.firestonebpco.com/roofing/asphalt/sbs/

The detail work is about as complicated, or not, as shingle work.
 

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Discussion Starter · #4 ·
You guys are bumming me out :-(

I am surprised that it is not do-a-ble. A very reputable pro roofer said he could do it with shingles. I guess it could be a little steeper than 2/12 I will have to take a better measure on it today.

Thanks

Dave
 

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Shut in w/o Home
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You guys are bumming me out :-(

I am surprised that it is not do-a-ble. A very reputable pro roofer said he could do it with shingles. I guess it could be a little steeper than 2/12 I will have to take a better measure on it today.

Thanks

Dave
Most dimensional/architectural shingles are spec'd down to a 2/12 with special underlayment considerations. I know some of them have abandoned the double felt spec in favor of I&WS.

I've have done this installation several times over the last 20 years and have had no problems. Is it the best solution? Probably not, but it can be done.
 

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I am not a roofer or play one on TV or the internet. But I've lived in a house with a 2.5 in 12 pitch for 20 years. Shingle roof. Standard felt. No leaks or problems. I'm also getting a new roof this week. (That's why I'm checking this forum) Keeping my fingers crossed.
 

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Shut in w/o Home
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The roof is 2.4/12 does that help? I am torn as to what I should do. Many roofers tell me that double felt ($60.00) is all I need or I can do a ice/water layer ($300)

Google the brand/model of shingle you are planning on installing and read the installation instructions.

Edit: And it's half lapped felt, not double felt. They're two different things.
 

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Pro Slate Roofer
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If you're bound and determined, use roofing nails. HDD, not those EG felt nails. They'll be brown dust in no time.

I did it once about 11 years ago. [URL]http://rcs.si-sv2628.com/show_album_photo.asp?userid=30&AlbumID=288&file=1976&s=0[/URL]
I&W shield. Elks, at a 4" exposure, HDD nails. I dutch-lapped the shingles about 6" to 10", random lap widths, so there are NO joints. It's still going strong.
Old School, but the method does work.

You should also note that shingles today are NOT waterproof. Just water resistant. I've seen them leak in the center of a roof on 12/12 pitch. No holes tears, or other damage either. They just absorb water.

The ones in the pictures are undamaged in any way. 8 years old. The amount of water coming through was ruining the house. The pix were taken after a drizzly night.
 

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Pro Slate Roofer
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I am not a roofer or play one on TV or the internet. But I've lived in a house with a 2.5 in 12 pitch for 20 years. Shingle roof. Standard felt. No leaks or problems. I'm also getting a new roof this week. (That's why I'm checking this forum) Keeping my fingers crossed.
 

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old guy contractor
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Canadian Asphalt Shingle Manufacturers' Association has a nice brief on the concerns of low slope shingle applications.

http://www.iko.com/advantage/CasmaPdf/16-LowSlopedRoofs.PDF

You are right to be concerned about this application.
Just pay very close attention to details and don't skimp on materials.
I think I already heard you balk at $600 for Ice & Water Shield.
That's nothing when you can be confident that your roof doesn't leak.
 

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Residential Roofer
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If you're bound and determined, use roofing nails. HDD, not those EG felt nails. They'll be brown dust in no time.

I did it once about 11 years ago. http://rcs.si-sv2628.com/show_album_photo.asp?userid=30&AlbumID=288&file=1976&s=0http://rcs.si-sv2628.com/show_album_photo.asp?userid=30&AlbumID=288&file=1976&s=0
I&W shield. Elks, at a 4" exposure, HDD nails. I dutch-lapped the shingles about 6" to 10", random lap widths, so there are NO joints. It's still going strong.
Old School, but the method does work.

You should also note that shingles today are NOT waterproof. Just water resistant. I've seen them leak in the center of a roof on 12/12 pitch. No holes tears, or other damage either. They just absorb water.

The ones in the pictures are undamaged in any way. 8 years old. The amount of water coming through was ruining the house. The pix were taken after a drizzly night.
I believe the wetness your referring to is a combination of condensation and side lap moisture, just guessing tho seeing as how I didn't see it in person.

I did do an experiment with GAF timberline, Tamko heritage and Certainteed landmark (controlled) and neither of the shingles allowed water to pass through.
 

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Residential Roofer
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I am going to be roofing a building that has some areas that are 2 in 12 pitch. I am going to be using comp shingles and double felt. Please share any tricks or tips for making this roof water tight.

Thanks

Dave
The problem with low slope shingle roofs is every and any mistake during installation will result in 100's of dollars in damages later, and the later is normally just a few years or sooner.

The main thing is to find an installer (roofer) who you trust, has a proven reputation and most importantly knows your regional weather.

If it were me I would not install the shingles on any thing below a tru 3/12 with out full ice & water shield covering the entire deck (sheathing).
 

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Would the GAF stormguard be comparable to the ice and water shield? It never snow here and the weather in mild

Thanks

Dave
With out the threat of ice forming and backing up under the shingles the biggest problem would be wind driven rains, in that case the two ply felt may very well be enough.
 

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Discussion Starter · #19 ·
I would like to spend the extra money to put down GAF stormguard in the low slope part of the roof. I took a look at the box that the stormguard is packed in and it does not say anything about low slope roofs and it says that it should only be applied full coverage under metal roofs.

Does anyone have first hand experience using stormguard in large areas for low slope roofs?

Thanks for all the help

Dave
 
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