North side? Hmmm, I wonder if it is mold.Here in PA everything turns green from moss or black from mold,due to all the moisture in the air.Have you gotten up on the roof and looked real close? If the minerals are coming off the shingles,wait for a real hot day,carefully remove a cap shingle and see if a name is on it.Some manf place there name at the lap line (look for a tan tape).if they are wood thick butt shakes,,,,,,I Dunno. Good Luck!!!!

OH! if the stains are coming from the chimney or vent pipes,,it might be plastic roof cement bleeding.If thats the case,it would be impossible to identify.usually the bleed (if its a good brand) will eventually wash away.Real hot days tend to break the skin that forms over the tar and bleeding occurs during a rain.Hope this helps.

[ July 28, 2004, 06:07 AM: Message edited by: Groundshaker ]

 

Could be from the roofing nails. Look for a pattern. If there's no pattern it's back to all the things Groundshaker mentioned.

 

It is very likely you are seeing mildew, especially if the area doesn't get alot of direct sunlight. This being the case it is not a manufacturers defect. You can have it chemically cleaned (NOT powerwashed!!!) and to prevent reoccurance have a zinc strip added at the top of the roof plane. Every time it rains zinc will wash over the roof below; zinc kills mildew hence it and the stains won't return.

HTH,
Jeff

 

More than likely mold and/or mildew

 

Before you waste your time on a warranty claim, be sure the roof was installed correctly. Is there 15 lb felt paper underneath the shingles? Is there proper ventilation in the attic space? If yes to both, and the discoloration is not mold or tree sap, you might have a claim.

 

Here's one little tidbit I picked up when I re-roofed the house.

Typically, the shingle manufacturers warranty covers the cost of the material only. The majority of the costs of a new roof are labor and profit.

So, even if a warranty claim is honored, you still write a good sized check.

Jeff