How attached homes drain
Most row houses and brownstones have a flat or low-slope main roof that pitches toward the back of the building. Water leaves through one of three routes: a gutter along the rear edge, a scupper through a rear parapet into a conductor head and leader (downspout), or an internal roof drain connected to pipes inside the house. The front often has a decorative cornice that sheds little or no water, although some houses have front gutters or built-in gutters behind the cornice. See gutters for flat and low-slope roofs.
Shared gutters and neighbors
On many blocks, one continuous gutter runs across the backs of several houses, and downspouts may serve two houses at once. That creates practical questions:
- Who owns which part? Usually each owner is responsible for the section on their building, but a shared downspout or outlet may serve both.
- Repairs affect neighbors. A clog in your neighbor’s section can back water onto your roof.
- Replacement works best across buildings. A new seamless run joined to an old sectional one at the property line is a weak spot.
- Access may cross property lines. Crews may need permission to set ladders in a neighbor’s yard or step onto their roof.
Talk with neighbors before gutter work, and if possible replace shared runs together and split the cost. Put any agreement in writing.
Leaders, conductor heads and sewer connections
Leaders on older attached houses often connect directly to underground pipes that run to the sewer. In cities with combined sewers, some programs encourage disconnection where yards allow it; in dense blocks there may be no room. When leaders are replaced, check that the underground connection is sound. A cracked connection leaks into the foundation every time it rains. See disconnecting downspouts and underground downspout drainage.
Cornices and built-in gutters
Many brownstones and Victorian row houses have wood or pressed-metal cornices, sometimes with a built-in gutter behind them. When the lining fails, water rots the cornice and runs into the front wall. Repair or relining is specialist work, and in historic districts visible changes may need approval. See gutters on historic homes and box gutters on old homes.
Flat roof problems that look like gutter problems
- Ponding near the rear edge because the gutter, scupper or drain is clogged or the roof has sagged.
- Leaks in the top floor at the back wall from failed flashing where the roof meets the gutter or scupper.
- Overflow over the parapet during heavy rain because outlets are too small or blocked.
- Ice in scuppers and leaders in cold climates.
Many of these need a roofer as well as a gutter installer. Ask who handles the flashing between the roof membrane and the gutter or scupper.
Sizing for intense storms
A row house roof can be surprisingly large, and all of it drains to one or two outlets at the back. In cities where short, intense downpours are becoming more common, larger gutters and leaders and additional outlets make a difference. See downspout size and placement.
Access, safety and permits
Rear gutters on three- and four-story attached houses are high and often above small yards or alleys. Crews may work from the roof, from tall ladders in tight spaces or from scaffolding. In some cities, work that uses the sidewalk or requires scaffolding needs a permit. Ask how the crew will reach the gutter, protect neighbors’ property and keep debris out of yards.
Front gutters and cornices
Some row houses have a front gutter behind the cornice or a hanging gutter at the front eave, especially where the roof slopes toward the street. Front leaders often run down the facade and connect to the sewer below the sidewalk. Because the facade is the most visible part of the house, front gutter and leader work in historic districts often needs approval, and copper or painted metal is usually expected.
Materials that suit attached homes
Heavier-gauge aluminum or galvanized steel handles the long rear runs and tall leaders common on attached homes. Copper suits historic facades and lasts for decades. Whatever the material, joints between your section and a neighbor’s must be sealed carefully, and metals must be compatible where they meet. See gutter materials compared.
Maintenance tips for attached homes
- Check rear gutters, scuppers and drains in spring and fall, and after heavy storms.
- Coordinate cleaning with neighbors if gutters are shared.
- Keep roof drains and scupper strainers in place.
- Look for stains on the rear wall and top-floor ceilings as early signs of problems.
Renovations and additions
Rear additions, roof decks and bump-outs on attached houses change how the roof drains. A roof deck can block the path to a rear gutter; an addition may create a new low roof that needs its own gutter or scupper. When planning a renovation, have the architect or contractor show how every roof surface drains and where each leader goes. Adding a roof deck without rethinking drainage is a common cause of leaks.
Party walls and flashing
Where your roof meets a neighbor’s taller or shorter building, flashing along the party wall keeps water out. Water from a neighbor’s higher roof may pour onto yours, overloading your gutter or scupper. If a neighbor’s leader discharges onto your roof, talk with them about extending it to their own gutter or to the ground.
Licensing in big cities
Several cities with large stocks of attached homes regulate home improvement contractors. New York City, for example, requires a Home Improvement Contractor license and specifically includes gutter work. Pennsylvania requires most home improvement contractors to register with the Attorney General. Ask for license or registration numbers and verify them.
Winter on attached homes
In cold cities, rear gutters and leaders on attached homes freeze, and ice backs up at flat roof outlets. Heat cables in scuppers, leaders and gutters can keep a drainage path open, and insulation and air sealing at the top floor reduce melting on the roof. Ice falling from high rear gutters into small yards and alleys is a hazard; keep gutters clear and well attached. See heat cables for gutters.
Where attached homes are common
New York City, Philadelphia, Baltimore, Washington, DC, Boston, Providence and Pittsburgh.