How to know if retarped valley was done correctly

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September 11, 2023 at 11:46 a.m.


Franco from New York asked:

If a non-licensed contractor retarped the valley between two semi-attached houses, how can you tell if it was done correctly? And… What are the minimum materials and procedures or preparations required to make sure he did an efficient job besides the rolls of rubber?

September 11, 2023 at 11:47 a.m.

From the photo you supplied, this does not look like a proper repair. On the right side of the valley, it appears that the new membrane has been installed and sealed with roof cement tying into but sealing correctly to the existing shingles. On the left side of the valley, the membrane is cemented on top of a course of shingles. You can see the cutouts of the shingles through the cement. This will leak if it has not already.
I recommend having a local professional roofing contractor come out and make a proper valley flashing connection. Unfortunately, it is going to be more difficult this time around because the existing will have to be torn out and completely redone correctly.
September 11, 2023 at 11:48 a.m.


Marty Stout from Go Roof Tune Up had this to say:

The photo shows that it is not installed correctly. You should never have an unlicensed contractor work on your roof. Have a properly licensed and qualified contractor do the job correctly. Your local roofing supply store can most likely recommend someone.

September 11, 2023 at 11:49 a.m.


The R-Club map from Project Map It can help homeowners and building owners find licensed contractors in their area:

September 17, 2023 at 11:20 p.m.


Determining whether a re tarped valley was done correctly involves several key aspects. First check the alignment and positioning of the new valley flashing to ensure it channels water effectively. Inspect the seams and connections to ensure they are securely sealed and watertight. Additionally examine the quality of the roofing material used and make sure it is properly secured and overlapped. Its advisable to consult with a roofing professional who can perform a thorough inspection and provide you with a definitive assessment of the works quality and integrity.

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