Built-In Box Gutter Repair in Philadelphia
Box gutters are built into the roof edge or cornice of older Philadelphia houses, so when they leak, water goes into the wall rather than onto the ground. Relining them properly keeps the historic look and stops the damage.
A box gutter is a wooden trough built into the roof edge or cornice and lined with metal, common on older Philadelphia townhouses. When the tin lining rusts or cracks, water leaks straight into the cornice, wall or ceiling. The fix is relining the gutter with new metal or a compatible membrane, repairing any rotted wood framing, and making sure the outlet drains.
How a Box Gutter Works and Fails
Instead of hanging off the fascia, a box gutter sits inside the building's edge: a wood box lined with soldered tin or copper, pitched to an outlet that feeds the downspout. It is hidden behind the cornice, which is why many older houses look gutterless from the street.
Its weakness is the lining. Old tin rusts at the seams and low spots, solder joints crack with expansion, and past repairs with tar trap water against the metal. Because the gutter is inside the roof edge, a small leak soaks the wood framing and the cornice before anyone sees it.
What Sets the Price of Box Gutter Work
- Length of gutterRelining is priced by the run.
- Lining materialCopper and tin cost more than membrane.
- Rotted framingSoft wood is rebuilt before relining.
- Outlets and leadersNew outlets and leader repairs add parts.
- Access and heightStreet-side cornices may need staging.
Box gutter repairs vary with the length, lining and hidden rot, so we price them after opening a section of the gutter.
Relining Built-In Box Gutters
Relining replaces the failed lining inside the existing wood box. On historic houses that usually means new tin or copper, formed to the box and soldered at the seams, with expansion joints on long runs. Elsewhere, a membrane lining compatible with the roof can be used. Either way, the old tar patches come out first, the wood is checked, and the new lining is lapped under the roof covering so water cannot get behind it. Relining keeps the house's original look from the street.
Box Gutter Outlet and Leader Repair
The outlet, where the box gutter drains into the downspout or leader, is where many box gutters fail. Corroded outlet tubes, loose connections and clogged leaders make water back up and overflow into the wall. We replace the outlet with a new soldered or flashed tube, add a strainer, and reconnect the leader so water drains all the way down. Philadelphia rules require roof water to stay on your property and flow into the sewer connection, not across the sidewalk.
Rebuilding Rotted Gutter Framing
Years of small leaks rot the wood that forms the box and the rafter ends and cornice blocking around it. Relining over soft wood does not last, because the new lining has nothing solid to hold or fasten to. We open the gutter, cut out rotted boards and blocking, rebuild the box to its original shape and pitch, and then line it. Where the cornice itself has been damaged, it is repaired in the same job, covered on our cornice repair page.
Water coming through the cornice?
Call and we open the box gutter and find the leak.
What We See on Philadelphia Roofs
Philadelphia's historic townhouses, including many Federal and Georgian houses, were built with tin-lined box gutters that need specialized care and period-correct materials when they are repaired. The City's rowhouse guide adds that roof water has to end up on your own property, draining into the sewer through the downspout's cast-iron boot, so a box gutter repair is only finished when the water reaches that boot.
How a Box Gutter Repair Runs
- 1
Inspect the gutter
Lining, outlet, leader and wood checked.
- 2
Photos and scope
What has failed and the lining options.
- 3
Remove old patches
Tar and failed lining stripped out.
- 4
Rebuild the box
Rotted framing replaced and pitch restored.
- 5
Reline and connect
New lining soldered or lapped, outlet fitted.
- 6
Water test
Gutter flooded to confirm it drains.
Signs a Box Gutter Is Leaking
Stains high on an outside wall
Water is leaking inside the roof edge.
Peeling paint on the cornice
The box behind it is wet.
Water dripping from the cornice
The lining or outlet has failed.
Tar patches in the gutter
Old repairs are trapping water.
Overflow in heavy rain
The outlet or leader is clogged.
Soft wood at the roof edge
Framing has started to rot.
Box Gutter Questions
Sometimes, but on historic fronts it changes the look and may need approval. Relining keeps the original design.
Copper lasts longest and suits historic houses; membrane linings cost less.
Usually the outlet or leader cannot keep up and water backs up over a weak seam.
Only briefly. Tar cracks and traps water against the metal, speeding up rust.
At least twice a year, more under trees, since clogs overflow into the wall.
More Exterior & Water Management Work in Philadelphia
Stop Water Leaking Into the Walls
Call and we find where the box gutter is failing and reline it properly.