Install flashing on existing roof

I have a leak where my porch roof attaches to the side of the house. I’ve seen it drip twice, both times in a storm when the wind is blowing hard (normal rains there seems to be no drip coming through). I have not been up on the roof yet to check, by my guess is that the guy who flipped the house did a terrible job on flashing (or didn’t install it at all) when he put a new roof on the house. House has vinyl siding.

Question: Can I install flashing or some type of protective barrier without tearing the shingles off the roof, and starting over? If so, how?

Thanks for any and all advice!

We need some pictures of the area you are talking about.

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The guy who did this bent down the j-channel and filled with caulking (and did a terrible job of caulking) between the j-channel and shingles.

Here is an image.

Is that aluminum or vinyl siding? It looks like they just butted the shingles to the siding and caulked. The proper way to flash that is to remove the bottom pieces of siding, install step flashings under every course of shingles that goes behind the siding, then reinstall the siding. If it is vinyl siding it is not too difficult, if it’s aluminum it’s a much bigger pita. Burrying the j channel in the shingles is going to leak, it needs to be on top of the shingles. Was the old roof torn off?

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The j-channel is aluminum, but siding is vinyl. What you describe is dead on. The moron tore off the old shingles, put new on and didn’t put any flashing—even I knew to do that!!! My question is how do I get this step flashing under the shingles? Do I have to tear off the roof, or can I pry up the current shingles? Thanks again for the help!

You should be able to carefully remove the shingles and install your step flashings. The seal on arch. shingles can be a bear when it’s hot out. Try lays a bag of ice on them for a bit and then break the seal with a flatbar. Good luck!

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Thanks for the reply and the tip on separating shingles. Guessing I should replace the j-channel while I’m up there?

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Be kinda silly not to, that alum. J looks to be flattened out some. Be easier to just get some new vinyl J.

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Yes…the guy who did this bang up roofing job flattened the j-channel against the shingles and then put caulking between. Thanks again for the advice!

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We are thinking about installing stepped copper flshing on top of existing aluminum flashing so we don’t have to pull up any shingles. Is this a good idea or is the metal dissimilarity going to be a problem? The existing aluminum flashing is working fine - no leaks but it looks ugly. We are planning on cutting it to a shorter height then installing copper on top. BTW we hade the chimney rebuilt since this photo but the original fashing is still there. Any advice would be greatly appreciated.

You need to remove the existing aluminum flashing before installing copper flashing.

When the new copper counter flashing is installed you should cut a reglet 2" above where the existing aluminum counter flashing is.

You will need to remove and replace the shingles around the chimney also.

If done correctly the copper flashing will be reusable for at least a couple roofs.

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No installing copper over aluminum is a bad idea. If you are simply looking to dress it up and not for function your best bet is to install a painted aluminum over the old instead. If you go copper you’ll need to replace everything with copper and remove existing shingles to do so. If its not having issues i’d wait till the roof needs replaced to do that.

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Thank you so much for your reply - I’m a little worried because my husband doesn’t want to pull up the old shingles fearing it will cause a leak. He said he wants to trim down the aluminum to a shorter height, prime the aluminum to protect it from the copper than apply and soldering copper step flashing. He also wants to use some eternabond roofing tape underneath the copper. Sounds like a kluge to me

Removing and replacing the shingles around the chimney is required to flash the chimney correctly.

Like others said, if it isn’t leaking or otherwise a problem do the chimney when the roof gets done next.

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Just put a coat of paint on it until the roof gets replaced
Unless it is leaking

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Yeah i’m really gonna suggest you don’t go with your husband’s idea. Really sounds like your asking for trouble. Replace it right (copper everything) or dress it up with some painted aluminum flashing for the time being.

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