Why Is My Roof Leaking After a Roof Replacement?

Flashing is the metal or rubber material that seals roof edges, around chimneys, and at valleys where two slopes meet. If the flashing was installed poorly or with the wrong fasteners, water can slip behind the new shingles. Look for gaps, rust, or lifted edges that could let rain in.

Valleys are another common trouble spot. If the underlayment or ice-and-water shield was not extended far enough, water can back up under the shingles. Inspect the valley from inside the attic, especially after a heavy rain. You may see dark streaks or damp spots that trace back to the flashing.

The underlayment is a waterproof membrane that sits beneath the shingles. If the roofer reused old underlayment or installed it with too many fasteners, it can tear or shift. A small tear can channel water into the attic, even if the shingles look perfect.

You can check the underlayment from the attic side. Look for wrinkles, tears, or areas where it has pulled away from the deck. If you find damage, the roof may need to be opened up in that spot to patch the membrane. This is a job for a roofer, not a DIY fix.

If you cannot find the source of the leak, or if you see water stains spreading on ceilings or walls, it is time to call a local water damage pro. They can use moisture meters and thermal cameras to trace the water path without tearing up your new roof. They can also dry out wet insulation and drywall to prevent mold.

A pro can also identify whether the leak is from the roof or from a pipe. If the leak is from a pipe, a plumber may be needed. If it is from the roof, the roofer may need to come back and fix the installation error. Either way, catching the leak early limits damage to your home.

• Water stains on ceilings or walls
• Damp insulation or musty odor in the attic
• Visible daylight through the roof deck
• Sagging or discolored drywall
• Mold growth on wood or drywall