My roof was recently completed, and I discovered that the roofers installed three closed valleys without the 36-inch waterproof membrane on the deck required by both the shingle manufacturer's instructions and California code.

Instead, the valleys rely on the shingles and regular nailed-down underlayment. They admitted it was not installed but didn’t admit it was not up to code.

I believe I have grounds to require the roofer to correct the installation because it doesn't meet code, but I'm concerned about the risks of tearing apart a brand-new roof, patching nail holes, and reinstalling the shingles, especially with an unhappy crew doing the repairs.

So my question for experienced roofers is: Would you insist on having all three valleys redone properly with ice and water shield, or would you leave them as-is?

I'm weighing the risks of potentially compromising an otherwise finished roof during repairs against the long-term risk of leaks, particularly 10–15 years from now as the shingles age.

What would…