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"Weaving" of shingles in roof valleys and a few other questions...

"Weaving" of shingles in roof valleys and a few other questions...

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Old 05-04-15, 02:40 PM
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"Weaving" of shingles in roof valleys and a few other questions...

We recently got some quotes on a roof replacement and have some conflicting info to sort through:

One company says that the way the valleys on our roof are weaved is not the best way to lay shingles in a valley, while another said it's the best way. Any opinions as to whether or not the weaving of shingles is recommended? Why or why not? See the link below to see what I'm talking about.

http://s1098.photobucket.com/user/hi...jjar.jpeg.html

Also, one roofer said that we don't need drip edges as the builder used a "pressure bend" technique using aluminum as part of the gutter system (see link above for what I think he's seeing). Of course, the other company said they would recommend putting the drip edges in where we have gutters.

Finally, one company planned on replacing our rotten sheathing with OSB, while the other one said plywood was better. As long as they use quality underlayment, does the board type really matter?

For each of these issues, is one way better than another?

One other question too. We have the option of either having the shingles hand-nailed or nailed with a nail gun. We've read hand nailing is better because they have more control and it's less likely for nails to be nailed through a shingle. Any thoughts?

Thanks in advance.

Andy
 
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Old 05-04-15, 02:56 PM
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Nailing

it's less likely for nails to be nailed through a shingle. Any thoughts?
If the nail does not go through the shingle, what will hold the shingle on the roof?
 
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Old 05-04-15, 03:16 PM
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Wirepuller... I think he means "clear" through. As in, making a hole in the shingle by driving it too tight.

You will get a variety of answers to all of your questions. Anytime there is more than one way to do things, you will get opinions one way or another... one way is not necessarily right or wrong. So take that FWIW.

Personally, I would NEVER weave a 3 tab shingle. Mainly it just looks like crap, but there is also a greater leak potential due to the tabs and the butt joints being in such close proximity (with end usually only offset by 6"). There are 2 main ways to weave a valley. You can lace it back and forth, with one shingle on one side, then one overlapping that on the next, etc. IMO this looks bad because the 3 tab pattern can never follow the angle of the valley exactly so it always looks crooked, running off center, then jumping back again. A 2nd way is to run the shingles on one side ONLY first (the lower of the two roofs), then the other side (the higher side) overlays and is cut off straight. This looks straighter but is usually not a great plan since fast running water and ice dams can cause this sort of valley to leak. Third way looks like the way your past roofers did it... goofy as hell. Looks like they slipped some diagonal shingles in wherever they felt like it. With 3 tabs, my policy is to always use an open valley, or if the customer wants the look of a closed valley, I will use a metal W valley flashing and cut the shingles tight to each side of the center peak of the valley. ^

Now if you are switching to a different style of shingle, lets say a laminated architectural shingle, I would definitely recommend the 2nd way i mentioned above. I prefer to weave valleys when using this type of shingle. This is usually the way the instructions on the shingle package will suggest, or at least is similar. A variation is to run a shingle lengthwise up the overlapping side of the valley and then start the shingles from that point and run them out and away from the valley.

I'm not a big fan of the way the existing aluminum is bent, and it probably does not provide any protection for the roof deck the way it is done unless it extends under the shingles 2 1/2" or so. Depending on how they bent it, it might be possible to score that lip, bend it a couple times, and break it off so that real drip edge could be used. You should use gutter apron flashing over the gutters and a d-style drip edge on the rakes (if it's deemed the existing fascia isn't providing adequate protection.) Its also possible they could accidentally bend up your fascia as they rip off the old shingles.

I would probably agree that plywood is a little better than OSB but that is a mute point if the decking never gets wet, which it shouldn't. If the deck gets wet, you will have a leak either way. Many would argue that OSB will rot quicker, which I HAVE experienced to be true in doing repairs to others work. I think it's a dumb argument because if the decking gets wet it's not the fault of the decking. I use OSB on the roofs I work on and am not afraid to use OSB and have not had any call backs on any of the roofs I have done. Either way, the decking gets covered with 2 rows of ice and water along the eves, one along the rakes, one down each valley, then I use #30 felt paper over the remainder.

If someone wanted me to hand nail a roof I would either ask to get paid by the hour or would tell them to have a nice day and wave as I drove off. I haven't nailed by hand since I was a young pup. There is no reason that a roof can't be nailed with a gun if the person using it knows how to use it and knows how to adjust his air pressure and/or the power with which he hits the shingle with the gun. (I would NEVER use a stapler, however!) Nails are surely set correctly when you do it by hand, but nowhere do shingle mfg's make that a requirement. When it's hot and sunny, shingles do get soft and you have to watch that more carefully. But you can also avoid it by not laying a bunch of shingles out in the sun unnecessarily, as they usually stay cool inside the package and won't be soft if you do it that way.
 
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Old 05-05-15, 06:03 AM
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Xsleeper was correct. I was referring to the nail going completely through the shingle if the air pressure of the nail gun was set too high.

I should have mentioned that we are switching from the "builder grade" shingles to the architecural shingles. We think these look much nicer than what we have.

Xsleeper, you said that if we go with architectural shingles you'd go with the 2nd way you mentioned, but you said that way isn't good because ice dams can cause leaks. Did I misunderstand you on that one?

Your comment on hand nailing vs. nail gun makes sense. If they have an adequate air tank and have things set correctly, it should be OK. But you really don't know how proficient the roofers are with the nail gun, so it's really a "Hail Mary" in that respect. You won't really know if they did it right until AFTER the job is done (and only if you spot check the roof in several places).
 
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Old 05-05-15, 06:21 AM
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In our area you almost never see shingles weaved in the valley except on very cheap installs regardless of the shingle type. I also think it looks like crap.
 
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Old 05-05-15, 07:12 AM
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Its the 3 tab profile that makes the valley more prone to ice dams and leakage.

If a roofer lays the butt end of a 3 tab shingle right in the center of a valley, the next 3 tab shingle that lays over the top will only provide 7" of coverage to the top edge of the shingle but only 6" of coverage left and right to cover that butt joint... and only about 2" to the top edge of the underlying shingle where the tabs are. When that shingle is curved due to the valley, that means that water is only about 3" away from that underlying butt joint horizontally and 2" vertically, and all the water is being funnelled toward the center of the valley... right below the location where the butt joint is on the row below. Its a leak waiting to happen. A little dirt or ice can easily cause those type of valleys to leak. Plus capillary action can easily draw water uphill against gravity on a low pitched roof.

This is not usually a problem with architectural shingles because they don't have tabs. You will always have at least 7" of coverage for every row. Plus, when only one side is "woven" (as in the method most mfg's recommend) the shingles on that side make a continuous "valley" that runs up about 12" onto the other pitch. A smart roofer will make sure there are no butt joints in the valley by inserting a shorter piece of shingle "as needed" that is not IN the valley, so that only full shingles will lay through the valley. This almost eliminates any potential for leaks.

All shingled roofs are subject to ice damming. Its just that 3 tab roofs are probably 75% more likely to leak due to ice dams as compared to architecturals.
 
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Old 05-06-15, 08:52 AM
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Thanks for clearing that up. We'll make a point of asking that no butt joints be used in the valleys. Makes sense.

Andy
 
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