Can you install drip edge after the gutters are already up?
Short answer. Yes. A roofer can slide drip edge or a longer gutter apron under the first course of shingles along the eave, lapping its lower leg into the existing gutter, often without taking the gutters down. It takes care to avoid breaking shingle seals, and on roofs with rotted fascia or badly pitched gutters it is better to remove the gutters and do it right.
How it is usually done
- On a cool morning, the installer carefully unseals the first course or two of shingles along the eave.
- Gutter apron, which has a longer vertical leg than standard drip edge, or drip edge is slid up under the shingles and, ideally, under the underlayment.
- The lower leg is tucked into the back of the gutter so water drops into the trough instead of running behind it.
- The flashing is fastened where shingles will cover the nails, and the lifted shingles are resealed.
When to take the gutters down instead
- The fascia behind the gutter is soft or stained, a sign water has been getting behind the gutter for years.
- The gutter is pulling away, sagging, or pitched wrong.
- The roof is old and brittle, so lifting shingles would crack them.
- The roof is being replaced anyway; then drip edge goes on with the new roof and the gutters are reset to it.
Why bother
Without drip edge or gutter apron, water clings to the edge of the shingles, curls back under, and runs down the fascia behind the gutter. That rots the fascia and the deck edge and stains the soffit. The residential code has required drip edge at the eaves and rakes of asphalt shingle roofs for years, so a newer roof without it is a red flag. See drip edge explained and gutter sizing, seamless gutters and guards.