Composition Shingle Overhang

[Brian G]

I've been digging through a few manufacturer's specs today, but have yet to find where they say how much overhang there should at the edges (beyond the drip rail). Can anyone direct me to an authoritative source that states what is recommended?

Brian G.

Overhang Is Better Than Hangover [:-drunk]

[Paul MacLean]

Brian,

If you have a copy of the Residential Asphalt Roofing Manual from the Asphalt Roofing Manufacturers Association you'll find it in the middle of the book (page 31 in my old copy) under "Starter Strip."

"...The starter strip protects the roof by filling in the spaces under the cutouts and joints of the first course of shingles. It should overhang the eaves and rake edges by 1/4 to 3/4 inch."

[Brian G]

Thanks Paul, I'll try to dig that up.

I found a Reporter article that said 3/4 inch minimum unless you have a a metal drip flashing (1/2 minimum for that).

Brian G.

[Jerry Simon]

Brian, where you're at, I doubt if you're worried about heavy snow & ice breaking the excessivley-overhanging shingles...we do up here, though.

[JEuriech]

From CertainTeed : The starter strip should overhang the rakes and eaves 1/2" when drip edge is used or 3/4" when no drip edge is used.

See Shingle installation at: http://www.certainteed.com/CertainTeed/ ... hingle.htm

Jeff Euriech

Peoria AZ

[Brian G]

Thanks for the input gents. I've written 'em up for too much and too little, but all in clearly unacceptable cases. I've never gone around measuring, this was just a minor side issue in a larger debate.

"The overhang of the shingles at the edges was only 11/16ths, where the minimum is 12/16ths according to manufacturer's specifications. I recommend replacing all of the overhanging shingles at the correct length."

Yeah, that'll make me a lot of new friends. [:-dev3]

Brian G.

Mr. Picky Strikes Again! [:-magnify

[Chad Fabry]

This is to confirm that GAF Materials Corporation recommends a minimum of 3/8" overhang to create a drip edge at the rakes edges and eaves of the roof. If drip edge metal is installed, the shingle edge should measure 3/8" from end of facia board under the drip edge metal. GAF Materials Corporation does not have a maximum length.

That's a reply I got from GAF today.

[Brian G]

Interesting. If a house has water damage and rot at a few places around the fascia and soffit and the shingle overhang looks adequate, what's the most likely cause? Leaks from higher up? Underlayment problems? Other?

Brian G.

Admittedly Other [:-dopey]

[Chad Fabry]

Around here the cause would be ice dams. Is the felt on top of the drip edge? Were there signs of condensation in the attic? Do the owners clean the roof with a hose from the ground?

[Bob White]

My own home sufferd soffit/ fascia damage and rot due to gutters overflowing and dumping extra water back into the attic / soffits . . .

It happened during a summer much like this one -- way to many frog drowning rainstorms in too short a period of time. Ended up tearing the gutters off (until the woman who runs the house made me get gutters back up). . .

Bob White

[Brian G]

It can't be ice dams down here, that's for sure.

To be honest I don't remember exactly how far out the felt came...I thought that might be an issue myself, but not until I was back here (brain cramp). I'll check it when I'm going past the house again.

No condensation in the attic, typical / functional ventilation. No gutters. I'm sure the roof has never been cleaned.

Brian G.

You Boys Clean Your Roofs? Really? [:-bigeyes

[mcramer]

Originally posted by Brian G.

Thanks for the input gents. I've written 'em up for too much and too little, but all in clearly unacceptable cases. I've never gone around measuring, this was just a minor side issue in a larger debate.

"The overhang of the shingles at the edges was only 11/16ths, where the minimum is 12/16ths according to manufacturer's specifications. I recommend replacing all of the overhanging shingles at the correct length."

Yeah, that'll make me a lot of new friends. [:-dev3]

Brian G.

Mr. Picky Strikes Again! [:-magnify

Shingle overhang doesn't matter. No one does it here in the land of endless rainfall. It doesn't cause any problems, assuming the felt is over the drip edge or the shingles are cemented to the drip edge.