How to spot hidden installation errors before paying for a new roof
Catching minor mistakes like missed nails or improper flashing early is critical because visible flaws usually indicate deeper, hidden installation failures elsewhere. Without catching these issues before final payment, homeowners are left dealing with chemical incompatibilities, leaks, and costly repairs that the original crew should have fixed.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Call the contractor back out to repair or replace the affected shingles.
- 2Cutting out and removing the incompatible material, then installing new EPDM and cover tape.
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“I found a few shingles with nails that missed the mark. Whats the best move here?”source ↗
“have them come out and repair (which is replace single)- if you have two shiners - you have more you are not seeing. . . .”source ↗
“Should I be concerned about this flashing that was done over the cover tape on a EDPM roof?”source ↗
“There was a small leak where the cover tape did not adhere and the roofer decided to add an additional step of Karnak / fiberglass tape / Karnak over the edge”source ↗
“Karnak 19 is an asphalt based product, which is chemically incompatible with EPDM. It will eat through the existing EPDM”source ↗
“Everywhere that got Karnak on it will need to be cut out and removed, then new EPDM and cover tape installed”source ↗
“No mang. They saved a few bundles by not over lapping enough... I'm sure there's other failures for instructions”source ↗
Where this came up
People with this problem also raised
- 25How to tell if roof flashing is installed wrong
- 4Can I install siding, soffit, and fascia before roof shingles?
- 2Is a gap in roof sheathing at the ridge okay before shingling?
- 4How to install drip edge on an existing roof
- 4Roofers left mono roof top exposed without a cap
- 17How to find where a roof leak is actually coming from