What do you do on slopes lower than 3/12?

Hey out there in roofing land..

Recently I lost a big bid because I suggested using modified bitumen instead of shingles on a low-sloped portion of a homeowner's roof (about 6 squares.) I understand that anything 3/12 and under should not be shingled over.. and that if it IS shingled over, the manufacturer won't warranty it. The customer said that he didn't want bitumen up there because it wouldn't look right, and that he got other roofers saying it wasn't necessary. I happen to think he went with the cheaper quote. What do you guys do on roofs that flat? Any input would be appreciated.

Just want to say thanks a lot. This is the absolute best place for feedback.

Don't know what I would do without you guys! Call me if you need a translator between you and your Spanish crews! Gracias :)

I normally ski on slopes like that. A "snowplow", On steep slopes I just turn faster!

that's some mighty fine torchin' there Moike!

I reckon you can say WANKER on here Mike.....you an' me's the only ones who know what it means :laugh:

The lowest pitch we use 3-tabs on is a 4/12 -- We will put a dimensional on a 3/12 either half lap felt or ice shield completly - on 3-tabs every rain slot starts an inch below the shingle underneath.

Also on three tabs the sealant is on the front instead of bottom of shingles -- so when nailing a 3-tab correctly you should be putting the nail about 1/2" up from the slot and 1/2" under the sealant -- on Dimensional the sealant would be covering the nail or below it so water cannot back up to the penetration as easy - sealant is on back and bottom.

We also use the peel n stick liberty - and is fairly easy to do i prefer this method on any 2/12 - 3/12 -- If below this pitch or flat We usually Use EPDM and tapered ISO to create some pitch.

Then again manufactures like to change their sealant strip every now and then We use GAF mainly. I know the old OC supremes used to seal down tight within minutes

---We have to occasionally roof 2/12 mobile homes. For many years our method is complete tear off and deck repair first. ---Then we install 2 layers of ASTM 15lb running 18 inch exposure which becomes to 2 layers. ---Then we install 3 tab style shingles (usually 30 year) at 5 inch exposure. We have to use AJC hammers for gauges as our guns only go down to 5 1/8th inch. We decline laminates for this slope...You can hardly see the roofing anyway at that slope and I think they do not lay flat enough for a 2/12. ---Finally we mastic UNDER all the pipe & vent flashings. We use metal vents and no-caulks rather than plastic as mastic & plastic do not mix. ---I have used this method for 20 years and have never had a call back. I do not live in snow country which would strongly recommend Ice & Water shield. Mobile homes are usually all straight gable with no valleys. There are some with valleys but we line the valleys and nail 12 inches away from the valley center. ---I recently roofed a friends house that was 2/12 and somewhat difficult. I required that we cover the entire house with Ice & Water barrier. As I remember it was 12 rolls at $90/roll or an additional $1,000. I wanted to install granulated torchdown rather than 3-tab but my friend was adament that he wanted shingles. So be it...pay for the Ice & Water. Actually we would have charged more for torch anyway. ---For the 6 sq job I would have popped out some granulated torch samples matching the comp and tried to convince the owner that it would hardly have shown from the ground. The lower the slope the less it can be seen from the ground. Lanny

Tinner thats one helluva job there bud! :cheer: They used to make dimensionals that overlapped/interlocked instead of butting together. However, they only overlapped like 1/8 inch or less which will still not stop the water from tracking over and under the shingles in extreme cases. :huh: We recently reroofed AND REDECKED a ladys home that had a 5/12 pitch with leaks here and there due to the old plank decking being unlevel. ( very old house ) 90% or more of the roofers around here would not have re-decked this house ( decking was not spaced more than 1/4 inch at the widest spot and wasn't that unlevel really but it was causing several leaks during hard rains not to mention a not so desirable appearance ) and she would of ended up with the same problems again ( probably sooner than later ) except newer shingles on the roof. :unsure:

You're not going to tick me off Egg. Yes, it's sidelapped, not butted. Manufacturer's rep recommended it. Said it was the same as weaving a valley. My own roof has withstood 70-85 mph winds during a hurricane.

When I was a factory certified installer, they watched me do this one, with their blessing also. I looked at it a month or so ago and it looked good for a 20 y.o. roof. No missing shingles either. http://rcs.si-sv2628.com/show_album_photo.asp?userid=30&AlbumID=108&file=764&s=0

Since the death of the low slope shingle we have installed thousands of squares of 3 tab shingles on 2/12 pitch roofs. 68" of ice and water protector at the eaves and 2 layers of felt paper on the remaining roof deck, with the shingles applied normally on top of that underlayment system. This system has worked very well in keeping out the rain. I can't remember a leak that was ever attributed specifically to the use of this system. Being in snow country, we do have some houses that are prone to ice damming. This system does ok in keeping the ice out, but not as good as the original low slope shingle.

Hay Willie , last time i checked , they had 4 colors, white, weather/wood, brown, charcoal. I was told they mite increase the colors in future , maybe already have. The roof in the pics was a 1/12, good and smoothe, but you are rite about the high spots-been dair--dun dat. ;)

fayette...http://www.gaf.com/Content/Documents/50391.pdf

Last sentence of first paragraph @ 4.1.1

All the other mfg co's have similar wording. At that pitch you need to beef up the underlayment. Read all that stuff there. It isn't terribly lengthy and explains a great deal that you will find useful in the future. You have to poke around in the websites looking for this kind of data because THEY are goofy, they think the PUBLIC is goofy, they assume the CONTRACTORS are goofy and so they make the easiest pages to get to the stupid goofy ones. The rest of us who want to make sense of the world have to work harder to find what we need to do that. Good luck with it. Don't worry, the learning curve isn't as bad as it seems at first.

P.S. on that Dutch lap thing...at the risk of ticking off Tinner, who is a very experienced roofer and not someone to ignore if he gives advice, (but...lol) what he means is to take the butt-joints of adjacent shingles and pull one shingle sideways up onto the other one to close that joint. He is the only respectable dude that I know of who will do this and I do not recommend it, nor do I think the manuf. would honor their warranty, at least so far as blow-offs are concerned, if you apply them this way. just my two cents on that one...

Hey Pot... That looks like a 2 - 3/12. Everything is usually fine unless some unlevelness develops with the decking. Another cause of the problem around here is fly by nights nailing over an existing roof improperly! As in not doing a butt and run. They cause slight humps all over the roof that damm up the water somewhat during heavy downpours and allow it to track horizontally to the butt joints and leak. Do they make peel n stick with shingle grain surface? Our customers like the low slopes to match the shingled part as much as possible. If they have low slopes we always recommend a color that is available in both the shingles and the modified. :)

Hay willie...you tried any GAF Liberty Cap Sheet,Peel n Stick....man, that mop grade sure is messy..

This a job 18 yrs old we did, maybe a 1/12 pitch we ran shingles on 3" lines , with only 30# felt under.......still holding out water today

http://rcs.si-sv2628.com/show_album_photo.asp?userid=148&AlbumID=907&file=6883&s=0

Then along came peel n stick...