How a Harrisburg rowhouse roof is put together
A typical city rowhouse has a main roof behind a front cornice and one or more lower roofs over the rear wings, each draining toward the back. The front may be a low-pitch roof barely visible from the street, or a steeper section with a dormer.
Neighborhoods like Allison Hill and Mount Pleasant were built out with brick rowhouses for factory workers from the 1870s into the early 1900s, and Midtown's historic district covers houses from the 1820s into the 1920s.
- Low-slope sections need membrane roofing, not shingles.
- Party walls on both sides need flashing that ties into the neighbors' roofs.
- Rear additions step down, so every step is a wall-to-roof joint to flash.
- Front cornices need their tops covered so they do not hold water.
Membrane choices
EPDM rubber, white TPO and modified bitumen all show up on Harrisburg rowhouses. Ask the roofer why they recommend one for your house, and how they will make sure water drains off every section rather than ponding.
Drainage first
Water sitting on a flat roof finds every weakness. A good proposal talks about slope, scuppers, gutters and downspouts, not only the membrane.
Working with the house next door
Where your roof meets your neighbor's, the roofer has to tie the new roof into the old one or turn it up a parapet. When both roofs are old, replacing them together gives one continuous roof and one well-made joint.
- 1Ask how the party-wall joint will be flashed.
- 2Find out whether the neighbor's roof is due as well.
- 3Plan ladder, dumpster and debris access on narrow streets and alleys.
Historic districts
Parts of Harrisburg sit in local historic districts, where the city's historic architecture board, known as HARB, advises City Council on certificates of appropriateness. Roof changes visible from the street, such as a new material on a front slope or changes to a cornice, may need approval first. See Harrisburg.
Questions
+How long does a rowhouse roof replacement take?
The roofing itself often takes a day or two. Access, debris removal and coordination with neighbors usually take longer to arrange than the work.
+Do I need a permit for a rowhouse roof in Harrisburg?
Pennsylvania's code generally treats residential re-roofing as exempt from a state permit, but municipalities can require one, and historic district rules apply separately. Check with the City of Harrisburg before work begins.