Hamilton Elite Roofing brings more than 20 years in the trade to roofing in Collingswood, and a large part of the planning here begins at a wall the homeowner does not own alone. When a house shares its roofline with the one next door, the estimate has to account for both sides of that line before a single shingle comes off.

That is the difference we want owners to see on paper. Our written scopes break out tear-off, decking, underlayment, flashing, ventilation and gutters as separate lines, so a second estimate can be laid beside ours and checked one item at a time. On an attached house we add the tie-in at the shared wall as its own line, because that is where an unclear scope turns into a leak.

We also start every leak call the same way: up on the roof and then into the attic, tracing the water to where it actually enters. Only after that do we tell you whether the roof can be repaired, and we give that answer before anyone mentions replacement.

Collingswood’s Twins and Row Homes

One half of a Collingswood twin re-roofed to the party wall, where the new shingles meet the neighbor’s side.

Collingswood is a borough in Camden County, about 5 miles east of Center City Philadelphia, and its housing is not only detached single-family homes. A real share of its streets are lined with twins and rows, and those houses ask for a different kind of roofing plan than a freestanding house on its own lot.

The Census Bureau’s 2024 five-year American Community Survey counts 6,901 housing units in the borough. Of those, 1,197 are one-unit attached houses, which works out to 17.3% of the housing stock, beside 2,704 detached houses. That is a large number of roofs that end at a party wall instead of a gable or an eave.

Most of those attached houses are lived in by the people who own them. The same survey counts 870 owner-occupied attached houses and 261 that are rented. For a roofing contractor, that means the person asking for an estimate is usually the owner of one half of a building, with a different owner living on the other side of the wall.

What the Zoning Code Calls Them

The borough’s zoning code treats these houses as a category of their own. Section 141-18 sets up the SF-D3 district, where the permitted principal use is single-family detached and semidetached dwellings. Section 141-19 creates the SF-A district, which the code says recognizes the mature residential neighborhoods made up of original row-homes and similar attached single-family homes.

The MF district also permits the uses allowed in SF-A, so attached houses turn up there as well. The code itself never uses the words twin or party wall; those are our trade terms. What matters on the roof is the building type the code describes: two or more homes under one continuous roof, divided by a shared wall.

Looking for roofing closer to Robbinsville? See Roofing in Robbinsville.

One Roof Across a Party Wall

On a twin or a row home, the roof does not stop where your property does. One roof surface runs across the party wall, and each owner holds the part above their own house. A new roof on one side has to meet the neighbor’s roof at the party-wall line, and the way those two surfaces join decides whether the seam stays dry.

Where Your Half Ends

Before we price anything on an attached house, we find the party-wall line on the roof and confirm it from inside the attic, where the wall usually shows as masonry or framing rising to the deck. That line is where our tear-off stops. Removing material past it means working on a roof that belongs to someone else.

On older rows the line is not always obvious from above. Previous re-roofs may have lapped one side over the other, or a coating may have been spread across both halves years ago. We photograph what we find and show it to you, so the plan starts from the roof as it is rather than as it ought to be.

Flashing at the Party Wall

Where a parapet rises at the party wall, the joint between roof and wall needs step flashing tucked under each course of shingles, with counter flashing set into a reglet in the masonry above it. We replace that flashing with the roof instead of reusing the old pieces, because worn metal under new shingles is a common source of leaks.

Where there is no parapet and the two roofs simply meet, we run self-adhering ice and water barrier rated to ASTM D1970 across the line before new underlayment and shingles go down. That membrane seals around nails and covers the seam where old and new material meet, which is the spot most likely to take in water during wind-driven rain.

Tying the New Roof Into the Neighbor’s Side

The tie-in itself is careful, slow work. We cut the old covering back cleanly at the line, weave or lap the new shingles so water sheds from the higher surface onto the lower one, and keep the neighbor’s material intact. If their shingles are brittle, we tell both owners before we touch them.

Ventilation crosses the party wall too. A ridge vent that stops at the line, or soffit intake blocked on one side, can leave both attics short of air. We check attic ventilation on every replacement, because a roof that cannot breathe ages from underneath, and on a twin that check covers how air moves at the shared wall.

Why an Attached House Is Permit Work in New Jersey

New Jersey’s construction rules treat a detached house and an attached house differently when it is time to re-roof. Owners of twins and rows sometimes hear from a friend with a detached house that a new roof needs no paperwork, and then find their own job works another way.

The Detached-House Exemption and Its Limits

Under N.J.A.C. 5:23-2.7, repairing or replacing the roof covering on a detached one- or two-family dwelling counts as ordinary maintenance and needs no permit. That exemption is written for detached houses. Attached houses fall outside it, so re-roofing a twin or a row home in Collingswood is permit work, as is any structural repair to the roof framing.

We build that into the schedule from the first visit, so the permit is not a surprise that pushes the start date back. Our estimate shows the permit as its own step and tells you what it means for timing. If decking turns out to be damaged once the old roof is off, we photograph it and show you before replacing it, at the per-sheet price written into the contract.

Historic Review Near Knight Park

Some attached houses also sit inside one of the borough’s historic districts. The Collingswood Historic Preservation Commission reviews exterior alterations in the Commercial and Residential Historic Districts, and its review covers replacement of roofs. The Residential district centers on Knight Park, and work done without approval there may bring fines.

Applications are due 20 days before the commission’s meeting on the third Thursday of each month, and the Zoning Office can confirm whether a property is inside a district. If your house is, we plan the materials and the calendar around that review rather than ordering shingles first and asking later.

What the Contract Says

Our contracts are written to New Jersey’s home improvement rules, including the notice of your right to cancel within three business days. On an attached house the contract also states where the work stops at the party wall, how the tie-in is made, and what happens if the neighbor’s side needs attention we did not plan for.

Talking to the Neighbor Before a Twin Re-Roof

We did not find a Collingswood ordinance on party walls or shared roofs, and we will not tell you one exists. Still, a re-roof on one half of a twin will be heard, seen and sometimes felt next door, so the practical step is a conversation before the crew arrives.

Why the Conversation Helps

Tear-off is loud, and debris can land near the neighbor’s walk or windows. Telling them the dates ahead of time saves friction, and it gives them a chance to mention leaks or soft spots on their side that could affect the tie-in. Their attic may show the same stains yours does, which helps us trace a leak that crosses the line.

We plan attached-home roofs with the neighbor’s roof and the shared wall in mind from the start. That includes keeping ladders, tarps and dumpsters off their property unless they agree, and cleaning the driveway, yard and gutters at the end of every work day, with a magnet sweep for nails on both sides of the wall.

When Both Owners Want a New Roof

Sometimes the neighbor’s roof is as old as yours, and both owners decide to replace at once. When that happens, each owner still signs a separate contract for their own half. One crew working both sides can run the underlayment and shingles straight across the party wall line, which removes the seam altogether.

That is worth asking about, but it is a choice between two owners, not something either one can require of the other. If your neighbor is not ready, we roof your half and leave a clean, sealed edge at the line, so their eventual replacement can tie in without tearing up your work.

When Only One Side Leaks

A leak near the party wall does not always start on the side where the ceiling stains. Water can travel along the wall, the flashing or the deck before it shows. We look at both the roof surface and the attic on your side, and with the neighbor’s permission we look at theirs as well.

Often the fix is a repair at the line, not a new roof. New flashing, a resealed joint or a few replaced shingles at the seam can end the leak for a fraction of what a replacement costs, and we tell you plainly when that is the case. If the roof is past repair, you hear that too, with the reasons written down.