Rowhouse and Twin Roofing in Trenton: Shared Walls, Shared Problems

Why is roofing a rowhouse different from roofing a detached home?

A row house shares walls and sometimes drainage with its neighbors, has little room for equipment and often has a flat section at the back. Work at the party wall affects the house next door, so the roofer must plan access, flashing and coordination as well as the roof itself.

On a detached house, a roofer can set a ladder anywhere and throw debris into a dumpster in the driveway. On a row, the frontage may be narrow, the street may be busy and the only way to the back roof may be through the house.

Those practical points show up in the price and the schedule, so ask the roofer how they plan to get materials up and debris down.

Do I need a permit to reroof a rowhouse in New Jersey?

Often, yes. Like-for-like reroofing of a detached one- or two-family home may fall under ordinary maintenance in New Jersey rules, but attached homes such as rowhouses and townhouses do not qualify, and rotted decking can make a job structural. Confirm with your municipal construction office.

The permit goes through the municipal construction office, which is the local arm of the state's building code. Ask the roofer who applies and whether the fee is in the quote.

The guide on roofing permits in Trenton and Mercer County explains the process. On the Pennsylvania side, ask the township or borough, since rules there vary.

What if my neighbor's roof is older than mine?

Water can cross the party wall from an older roof into a newer one, so a new roof on your side can show leaks that began next door. Talk to your neighbor, document the condition of the shared joint and ask the roofer to flash and cap it carefully on your side.

You cannot make a neighbor repair their roof, but good detailing on your side protects your house. Photographs of the joint before and after help if there is a dispute later.

The guide on replacing a roof on a Trenton rowhouse or twin works through this situation in more depth.

Does a historic district change rowhouse roofing?

It can. Trenton's Mill Hill historic district may require review by the Historic Preservation Commission for visible exterior changes, and other old districts in the river towns work similarly. Ask the municipal office whether your block is covered before choosing materials or changing the look of the cornice.

The review usually concerns what can be seen from the street: roof materials, cornices, dormers and chimneys. Flat rear roofs that are out of sight are less likely to be affected.

Do not assume your house is or is not covered. Check, and ask the roofer to confirm.

How do I talk to my neighbor about a roof job on a shared wall?

Tell them early, in plain words: what work is planned, which dates, whether access from their side or their roof is needed, and who to contact. Offer to share the roofer's findings about the shared joint. A neighbor who is told in advance is far more likely to cooperate than one surprised by a crew.

Row house roofs are small neighborhoods. The neighbor may have a roof of a different age, a different material and a different plan, and may or may not be able to afford to fix that side. You do not have to agree on everything. You do need to agree on access, noise and the line between your work and theirs.

A short note with the roofer's name, the dates and a phone number goes a long way. If the roofer needs to put a ladder in the shared passage or step onto the neighbor's roof, get permission first and do not assume it. If something goes wrong, the paper trail helps everyone.

Photographs of the shared joint before and after the work are worth taking. They show what you did, protect you if a dispute arises later and give a neighbor evidence to take to their own roofer. If the joint on your side is in good shape and theirs is not, the roofer's report gives you a calm, factual basis for the conversation.