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Reroof on top of a single layer of existing shingles.

What supplies do I need? Do I have to put down a layer of the black roll roofing on top of the current shingles?
Should I change the flashing?
I have a very low pitched roof that is easy to walk on and I am sure we can do it - just need to do it correctly
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Posted 2016-01-10T03:01:09+0000  by jataj jataj
Hi jataj,

The condition of the existing roof and decking is very important, you cannot just slap a new layer of shingles over an old worn out roof and not expect problems down the road.

Have a professional roofer inspect the house and give you a condition report. Most will do this as part of a bid for the job at no charge.

Get more than one inspection and bid. Once you have determined that the exiting roof can handle a second layer, contact your local building department for the specific code requirements for your area.

They will spell out in detail what you need to do to meet code and the materials that are required.


Posted 2016-01-11T18:50:44+0000  by Mike_HD_OC
Hello jataj.

Normally you would change the flashing and the roof stack boot flanges when doing a simple re-roof.  You would not put down an additional layer of felt paper, but just run the new shingles over the old ones.  At the peak you would replace the existing caps with new ones.

This all comes with a pair of caveats that Mike mentioned.  Any damage to the roof sheathing, in terms of rotted wood or physical damage means a tear-off is mandatory.  Also, badly damaged or cupped existing shingles will require a tear-off as well.

While local building codes may interveen here, normally any roof with a 4/12 pitch or greater can have a second layer of shingles added if done before the roof has become damaged.  Since this job will need to be inspected, when you pull your building permit ask for specific information on what is allowed and what is not.


Posted 2016-01-12T18:33:46+0000  by Chris_HD_CHI
Hi jataj,

Your geography will lend itself to the most accurate answer.

As you'll note, Mike is in California, Chris is in Illinois and I'm in Georgia.

Mike says, "You cannot just slap a new layer ..."

Chris says, "Pull your building permit ..."

And I say it is fairly common that one roof-over is allowed, if the existing shingles are not curled at the edges and the underlying structure is in good condition.

As you can see, it is a local issue that is "coded" by your local building authority.

Your best bet is to take Chris' instruction and then go to your local authority for exact detail about local requirements.

Hope this helps,

Pat InPaint

Posted 2016-01-26T20:54:30+0000  by Pat_HD_ATL
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