Shingle flashing(?) detail question
MikeHennessy
| Posted in Construction Techniques on
I’m starting to rebuild a dormer that has been butchered on several occasions in the past, so I’m not sure what the original detail was. What’s the best way to detail this intersection where the vertical shingles on the dormer wall meet the trim at the front plane of the dormer (See yellow arrow)? Should there be a corner board installed over the shingles to keep water out from behind the front plane? Flash & caulk? Something else?
[I see the pic pie is back again today – bummer. ]
Mike Hennessy
Pittsburgh, PA
Everything fits, until you put glue on it.
Replies
if you are using corner boards ( say 5/4 x 4.... or 5/4 x 6 )... you wrap the corner with Grace, maybe a 10" or !2" strip....
traditionaly this would have been a double 15 lb felt or a 30 lb felt corner, nowadays corners are an I&W detail
there is no caulk... and the shingles merely butt to the corner board, the Grace keeps the joint waterproof
corner boards DO NOT lap on top of shingles... that is a vinyl siding detail
also.... where the shingles meet the roof, there should be a 3/4" space so the rain will drip and not wick back up, we use black coil stock for the step flashings in this
Thanks, Mike. Yes, there is trim on the front, but presently none on the sides. I'll either add some or just run the front trim a bit wide and use I&W around the corner behind it, flashed at the bottom. I'm planning on using Azek for the trim, so I won't need to worry about water there.
There is a flashed gap between the side shingles and the roof -- I'm just sketchup challenged, so I didn't draw it. ;-)Mike HennessyPittsburgh, PAEverything fits, until you put glue on it.
What Mike said.
As an aside, AZEK makes a premade corner in 5/4 thickness and 3.5" on each face in case ya want to avoid a joint. Might not scale out on a house corner, but about perfect for a dormer.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
"If Brains was lard, you couldn't grease much of a pan"Jed Clampitt
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Yeah, I actually was thinking about that corner piece, but the front trim piece is about 10" since it works as both the corner and trim for the dormer window.
I'm now leaning towards Grant's method, but with the flashing only covering the back side of the trim board, or maybe turning the corner just a 1/4" or so for stiffness, and with some caulk behind it to seal it to the trim.
Or maybe running a kerf on the backside of the trim where it overhangs the corner and caulking the flashing into the kerf -- that way, everything is behind the shingles. The more I think on it, the more I like that one.
Guess I'll just get started and see how it turns out. ;-)Mike HennessyPittsburgh, PAEverything fits, until you put glue on it.
I'm gonna look and see if I can actually retrieve an old attachment of those dormers I did a yr. or so ago.
If I go poof, come find me.
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I don't have a "finished" pic I don't think, but I finished it out with something...LOL
Being Hardie, I didn't flash at all, just caulked the siding to the azek, I like your kerf plan.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
"If Brains was lard, you couldn't grease much of a pan"Jed Clampitt
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Nice dormers. But the siding I'd know how to do -- 1/8" gap & caulk. It's the shingles that have me scratching me head -- never did vertical shingles before. But hey, that's the way these dormers were originally built, and I've got the shingles, so that's how they're gonna get rebuilt.
Like I said, I think I'll just start building, keeping these tips in mind, and see what comes out the other end of the process. Gonna hafta find me a break tho', if I decide to go with the flashing.
Mike HennessyPittsburgh, PAEverything fits, until you put glue on it.
PS: What are the things that look like gutter hangers in your pic -- was it taken pre-gutters? And thanks for dipping into your pixel allotment to post that. ;-)
Edited 6/3/2009 7:58 am ET by MikeHennessy
Thems are the shanks (copper) for the gutter circles to bolt to. They go under the shingles and screwd to the sheathing.
They have holes as do the circles that allow you to slope in itty bitty increments when you bolt them together.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
"If Brains was lard, you couldn't grease much of a pan"Jed Clampitt
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there is no caulk...
Does the "no caulk" advice meet the local building codes? Does it meet the manufacturer's requirements on the underlayment, siding and trim pieces?
Wouldn't eliminating the caulk affect the air infiltration rate?
When you say "butt" to the corner board; does that mean tight, or do you leave a gap?
Are gaps required for expansion and contraction?
Lots of questions....I guess I probably should read up on these products.
jim, his question was about "shingles" butting a corner board
there is no caulk in that case
if it is clapboards butting a corner board then there should be a small gap ( about 1/8" or an 8d nail ) to allow caulk
my sequence then would be grace / corner board ( backprimed/primed )
apply corner boards ( backprimed/primed )
caulk
finish paintMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
Good observation Mike. I gotta learn to read better.
Mike -
Here's what I've done in that situation on occasion:
I install a "Z" shaped flashing (I've exagerated the clearances for clarity) before installing the side wall material.
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http://www.quittintime.com/ View Image
Thanks, Grant. But doesn't that leave the flashing exposed on the side of the trim -- or do you cover it with the corner piece?Mike HennessyPittsburgh, PAEverything fits, until you put glue on it.
But doesn't that leave the flashing exposed on the side of the trim
Yes. Yes it does. I can't do a hemmed edge less than 1/2", so I would make that piece so the hem is flush with the front of the corner board. It hides better when painted being flush with the front rather than creating another shadow line down the side of the board.
I've typically used copper so about half the time it doesn't get painted. Not that big of a deal - it ties in with the other copper flashing on the dormer. Painted, it's not there unless you're looking for it.
If there is a side corner board and not just the front board as you have pictured, I'd just show a 1/2".http://www.quittintime.com/ View Image