# Shingle overlay



## bluebird5 (Dec 13, 2010)

For those of you that do overlays from time to time, when you are laying archies over 3 tabs, do you but up to the old shingles and have a 5 inch reveal instead if the 5 1/2 it should be

or

Do you ignone the old shingles an put the archies so that they have the correct revel of 5 1/2?

I tried 2 seaches, but couldn't find any overlay info., but I know this has probable been covered before


----------



## davitk (Oct 3, 2008)

Yes, you butt so there are no voids under the new layer. However with ice damming and liability issues, I will no longer do them.


----------



## Stewy (Nov 11, 2007)

I am not a roofer but if I was doing my house I would be tearing off the old.


----------



## bluebird5 (Dec 13, 2010)

Stewy said:


> I am not a roofer but if I was doing my house I would be tearing off the old.


I would too, but this is what the customer wants. So I do it


----------



## matthewcims (Feb 15, 2009)

butt and run.


----------



## TimelessQuality (Sep 23, 2007)

You end up using 10-15% more shingles than the sqft...


----------



## Tom M (Jan 3, 2007)

I've done both. Never had an issue either way. Its better butt to avoid air pockets but sometime the existing is too sloppy to keep your roof straight.


----------



## MJW (Jan 27, 2006)

bluebird5 said:


> I would too, but this is what the customer wants. So I do it


Just make sure you can do it without violating any codes. Most of the states in the middle of the country do not allow a second layer. Even here in MN, we cannot do it.


----------



## jb4211 (Jul 13, 2010)

I agree with the others - complete tear-off is the correct way to go.

If that was what the customer demanded, I would have it in writing that the install comes with no warranty, i.e., when I'm done with the install, I'm done - period.

Don't call me if the shingles start curling or the roof fails prematurely, etc.


----------



## apkole (Mar 18, 2006)

If you are going over existing 3-in-1, nesting in the new roof is probably the best option. There is only one manufacturer, TAMKO, that I know of that still makes architectural shingles in "standard" exposure. I've installed a couple of overlays with good results using this brand. If you don't nest the metric (5 5/8" exposure), you wind up with an anamoly (ripple) every 6 rows or so due to the larger exposure shingle "creeping" up over the underlying shingle. It is readily seen from the street, and looks rough (and unprofessional).

My preference is to strip down to the deck and build it right. I don't encourage overlays, and really fight going that direction. If it comes out that finances are a challenge and water infiltration is an ongoing issue, we accommodate with a roof over, but usually only for people we are well aquainted with, who understand the limitations of this kind of install.

Tom is correct on going over an existing install that isn't straight. Customer needs to understand that what you roof over typically telegraphs through to the top layer with some heat and time. Our Michigan code still allows a second layer. There are a probably a couple of local municipalities that say only one layer (Ann Arbor comes to mind) but most follow the state.


----------



## jmiller (May 14, 2010)

matthewcims said:


> butt and run.


We always called it bump and run. Six of one...


----------



## A&E Exteriors (Aug 14, 2009)

Another option is to trim the existing tabs on any row that is not overlapped by at least 2 1/2"


----------



## erniesgutter (May 26, 2011)

butt so there are no voids under the new layer


----------



## room2roof (Feb 1, 2011)

Here in Charlotte NC you can have up to two layers of Roofing shingles but my company doesn't do this simply because you need to check the sheathing underneath and make sure no water damage is present.


----------



## jmiller (May 14, 2010)

room2roof said:


> Here in Charlotte NC you can have up to two layers of Roofing shingles but my company doesn't do this simply because you need to check the sheathing underneath and make sure no water damage is present.


So you refuse the work if they demand it?


----------



## jmiller (May 14, 2010)

room2roof said:


> Here in Charlotte NC you can have up to two layers of Roofing shingles but my company doesn't do this simply because you need to check the sheathing underneath and make sure no water damage is present.


P.s.
Spam is disgusting: http://www.roofingtalk.com/f6/do-i-tear-off-my-old-shingles-1628/


----------



## Donohue Const (Dec 31, 2011)

MN code does not allow overlays

I would argee with others though, even if overlays were allowed, tear off down to the roof deck or no warrany on the job


----------



## jmiller (May 14, 2010)

I hate overlays as much as the next roofer, but you can't argue quality over minimum code with someone who has to replace the roof on a house for sale due to a pushy buyer. Sometimes that's all the buyers deserve...


----------



## erniesgutter (May 26, 2011)

Two thumbs up on that one as well .... to the deck it saves time and headaches later on down the line REALLY ...


----------



## BrandConst (May 9, 2011)

Too many stipulations around here for overlays. You can only have up to 2 layers but if your doing a roof over around here there are too many steps involved that don't add up to the savings of leaving the first layer on so I typically recommend tear off.


----------

