What a built-in gutter is
A built-in gutter, often called a box gutter, is a wooden trough built into the eave or cornice of a house and lined with metal. The Wisconsin Historical Society describes them as metal-lined wooden boxes built into the eaves, lined with lead, tin, terne metal or copper, often with a crown molding on the front. From the street, you see a decorative cornice instead of a hanging gutter.
Built-in gutters were used on high-style buildings as early as the 18th century and became common on Victorian, Italianate and Colonial Revival homes and brick rowhouses. Cities with a lot of historic housing, such as Richmond, Philadelphia, Boston, Washington, DC and St. Louis, still have many of them.
Why they leak
Built-in gutters fail in predictable ways. The Wisconsin Historical Society and Roofing magazine both describe the same problems:
- Failed solder joints in the metal lining
- Worn-out lining, eroded over decades or punctured by branches and hail
- Rotting wood in the box and the framing behind it, once water gets past the lining
- Ice damming in cold climates, which pushes water over the back edge of the lining
- Settled eaves that change the slope, so water pools instead of draining
- Too little capacity for the roof area above
The trouble is that leaks run into the wall or soffit, not onto the ground. Stained plaster near the top of exterior walls, peeling paint on the cornice, soft wood at the eaves and water marks in the attic are the usual signs.
Repair, relining or replacement
Spot repair
Small leaks in an otherwise sound lining can be repaired by cleaning the metal and soldering a patch over the hole, as the Wisconsin Historical Society describes. That only makes sense if the rest of the lining is in good condition.
Relining
When the lining is worn out, the best approach is to remove the old metal and install a new lining, usually copper, terne-coated steel or another durable sheet metal, soldered at the seams. This is also the time to repair rotted wood in the box, correct the slope and make sure the outlet to the downspout is large enough. Some roofers offer membrane linings as a lower-cost alternative; ask how long they are expected to last and whether they are acceptable in your historic district.
Converting to hanging gutters
Some owners close up built-in gutters, roof over them and hang conventional gutters at the edge. It can be cheaper, but it changes the architecture, and in historic districts it may not be allowed. Richmond’s Commission of Architectural Review, for example, states in its gutter guidelines that installing suspended gutters where a box or built-in gutter is present will not be approved, and neither will replacing box gutters in a way that changes the appearance from the public view.
Maintenance that makes them last
The U.S. General Services Administration’s preservation guidance on gutters and downspouts stresses regular inspection and cleaning. For built-in gutters, that means:
- Clean out leaves and debris at least once a year, especially at the outlets.
- Look for standing water after rain, which points to slope problems.
- Check solder joints and the lining for cracks, holes and corrosion.
- Keep the paint on exterior wood trim in good condition.
- Check the attic side of the eave for water stains.
- In snowy climates, keep an eye on ice build-up and address attic heat loss. See ice dams and gutters.
Can the box gutter be saved?
A box gutter is usually worth saving if the wooden box is mostly sound, the rafter tails behind it are solid, and the problems are in the lining and a few soft spots. It may need rebuilding if the wood is rotten along long stretches, the eave has sagged, or water has damaged the framing. Only opening the gutter shows for sure, so ask the contractor to inspect and photograph the box before agreeing on the full scope.
Relining is also a chance to improve the gutter. Installers can adjust the slope, enlarge the outlet, add an overflow scupper so that a clog does not send water into the wall, and in cold climates add a membrane at the back of the box to protect against ice.
Built-in gutters and ice
In snowy regions, built-in gutters are especially exposed to ice dams because the box sits right at the cold eave. Keeping the box clean before winter, correcting attic heat loss and making sure the lining extends well up the roof behind the gutter all reduce the risk of water backing up into the wall.
Historic districts and permits
If your home is in a local historic district, visible changes to the roof edge usually need review before work starts. Relining a box gutter without changing its appearance is often straightforward; removing it or switching to K-style gutters is the kind of change reviewers look at closely. Richmond’s guidelines also say vinyl gutters, incompatible K-style profiles and rectangular or vinyl downspouts will not be approved in its Old and Historic Districts. Check your city’s rules before ordering materials.
Older homes often have lead paint on trim. The U.S. EPA’s Renovation, Repair and Painting Rule requires certified firms and lead-safe practices when paid work disturbs more than 20 square feet of exterior paint on a pre-1978 home.
Who to hire
Box gutter work is part carpentry, part sheet metal and part roofing. Look for installers or roofers with specific experience in built-in gutters and metal soldering, ask for photos of similar jobs, and get the scope in writing: lining material and thickness, wood repairs, slope correction, outlet size and how the new lining ties into the roof. When a hanging gutter is appropriate, half-round gutters with round downspouts usually suit older homes best.
Sources
- Wisconsin Historical Society: Built-in gutters
- Roofing magazine: Built-in gutters should be carefully inspected, restored and maintained
- U.S. General Services Administration: General inspection and maintenance of gutters and downspouts
- City of Richmond Commission of Architectural Review: Gutters and downspouts guidelines
- U.S. EPA: Lead Renovation, Repair and Painting (RRP) Rule