Roofing a shed dormer into the main roof


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Old 12-20-14, 04:38 PM
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Roofing a shed dormer into the main roof

I'm installing architectural asphalt shingles on a new garden shed I built which has a couple of shed dormers off the main roof.

The coursing is 5 1/2" as per the shingle.

The main roof coursing line is going to be about 4" higher than the shed dormer courses where the shed dormer meets the main roof near the ridge.

These are architectural / shadow line shingles ( GAF ). I was thinking of cheating the courses on the dormer roof to meet up with the main roof. Is this how it's done ? You won't really see the dormer shingles,... but it will negate the shadow line effect from a distance. The main roof coursing will be clearly seen. It's a 12 pitch.

What's standard roofing practice ?

Suggestions or Ideas ???

Thanks in advance,

Soybomb
 
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Old 12-20-14, 05:39 PM
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How steep a pitch are these dormers.
5-1/2 sounds like to much exposure on any shingles I've installed. Sure your not looking at the nailing line and thinking that where the end of the shingle should be?
I've seen done like that a time a two, and it failed.
If the dormers are a shallow pitch then the paper needs to be double up and the course are run narrower.
 
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Old 12-20-14, 06:14 PM
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The 5 1/2" exposure is what Gaf called for. It allows about 3/4" overlap of the nail line guide. The dormers are not a steep pitch. I can walk easily.
 
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Old 12-20-14, 06:17 PM
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Also, I ice shielded the whole top of the dormers to the ridge with 30# felt over that.
 
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Old 12-20-14, 06:50 PM
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5 1/2" is close to the standard exposure for any of today's metric shingles. If I understand you correctly, you would need to drop the exposure on the dormer down to lower those shingles another 1 1/2". Rather than do it all at once, you could drop the last 12 rows on the dormer 1/8"... or the last 6 rows 1/4"... or the last 3 rows 1/2"... so that when you have that one solid row above the dormer, everything meets up.
 
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Old 12-20-14, 06:53 PM
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Thats what I was wondering. sounds like a plan. Glad I thought to ask before getting too high.

Thanks !!!
 
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Old 12-20-14, 08:04 PM
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No problem. The more gradual you do it, the less obvious it will be from the ground... or in the case of your low pitch dormer... from an airplane. LOL! No one will pick up 1/4", for instance.

I would snap a chalk line to represent the top edge of that row that spans the entire roof and try to work all sections up toward it.
 
 

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