From: mg 
Newsgroups: alt.building.construction alt.home.repair misc.consumers.house
Subject: Re: Impact of not removing existing shingles?
Date: Sat, 19 Jun 2004 23:46:17 GMT

On Sat, 19 Jun 2004 18:46:20 -0400, AndrewJ 
wrote:

>
>>
>>Thanks in advance,  Jeff R.
>>
>>--- Other Info ---
>> We are in the Midwest.
>> Believe the existing shingles are asphalt organic felt (does this matter?
>
>No.
>
>> Some of the existing shingles have started to curl slightly.
>
>Should be ok if you choose a dimensional(cedar look) shingle.
>
>Guys putting up cheap shingles must do a tear off. Poor quality
>shingles look awful going over anything but sheathing. We put 30 year
>shingles over decent roofs all the time. It's called a "roof over" and
>exact directions are on every bundle sold. 99% of the country allows
>upto three layers of shingles with some regions allowing four.
>
--------Snip-------

NJ allows only 2 layers before tearing off is required and only have
to tear off 1 of the 2 layers if desired. I've seen that done to save
a buck.