Common Structural Problems We See in Philadelphia Rowhomes
Philadelphia rowhomes have character that is hard to replicate: original brick, narrow floor plans, historic details, and homes that have stood for generations. But their age, shared construction, and decades of renovations can also create structural conditions that are important to understand before beginning a project.
Through our projects at Jane Draws Plans, we see many of the same issues appear again and again throughout Philadelphia. Some are simply signs of an aging building. Others deserve a closer look before demolition or renovation begins.
Here are some of the most common structural conditions we encounter in Philadelphia rowhomes:
1. Deteriorated Floor Joists
One of the most common conditions we encounter is deterioration of the wood floor framing.
Traditional Philadelphia rowhomes commonly use wood joists that span between masonry walls, with the ends of the joists bearing in pockets within the masonry. Over time, moisture entering through the masonry can cause the ends of these joists to deteriorate.
During renovations, we frequently encounter joists that need to be sistered, reinforced, or replaced. We also see older framing that has been cut or modified over the years to accommodate plumbing, mechanical systems, stairs, or previous renovations.
The City of Philadelphia's Rowhouse Manual specifically identifies rot where joists rest in masonry pockets as one of the most common structural problems found in rowhouses.
2. Cracked and Deteriorated Masonry
Brick masonry is one of the defining features of Philadelphia's housing stock, but it also requires maintenance.
Some of the conditions we regularly document include:
Cracked brick and mortar joints
Missing or deteriorated mortar
Brick spalling and surface deterioration
Areas of previous masonry patching
Separation or cracking around window and door openings
Bulging or out-of-plane masonry
Cracking or deterioration at foundation walls
Not every crack means that a building has a major structural problem. Older masonry naturally shows signs of weathering and previous repairs. What matters is the location, pattern, width, and whether the condition appears to be changing.
Bulging, leaning, or significantly cracked masonry deserves particular attention because it can indicate movement within the wall or a loss of connection between the masonry and the building structure.
3. Altered Bearing Walls and Missing Support
Philadelphia rowhomes have often been renovated many times before the current owner ever gets the keys.
We regularly encounter evidence of previous openings, removed walls, patched masonry, added beams, altered headers, and framing that has been modified from its original configuration.
The problem is that some of these walls were originally doing more than dividing rooms; they were carrying loads from the floors or roof above.
Removing or enlarging an opening in a bearing wall changes the path that those loads take through the building. If the replacement beam, header, posts, or foundation support was not properly designed, the effects may eventually show up as sagging floors, cracking finishes, movement around openings, or other deformation.
This is one reason an "open concept" renovation in a rowhome can be more complicated than simply removing a wall.
4. Undersized, Cut, or Improperly Modified Framing
Older homes frequently contain a mixture of original framing and alterations from different periods.
During surveys and renovations, we see framing that has been notched, cut, sistered, replaced, patched, or modified around new openings and building systems. Stair openings are another common location where headers and surrounding framing have been changed.
The existence of altered framing does not automatically mean it is unsafe. The important question is whether the modified structure can still properly transfer its loads to the supporting walls, beams, columns, and foundations below.
When significant framing alterations are proposed, Philadelphia's structural plan review process specifically considers items such as joist spans, headers, girders, connections, and the overall load path through the building.
5. Party Wall Conditions
If you own a Philadelphia rowhome, your house is not structurally isolated from everything around it.
The masonry wall between neighboring rowhomes is typically a party wall. Floor joists may bear into these walls, and construction on one property can therefore have implications for the building next door.
During our surveys, party walls are one of the most important areas to document. Conditions we encounter can include exposed masonry, deteriorated mortar, cracking, previous infill or patching, framing connections, and areas affected by previous construction.
They become especially important when a project involves significant joist replacement, an addition, demolition, excavation, or direct modification of the party wall.
6. Water Damage That Becomes a Structural Problem
Water is behind many of the problems we see in older Philadelphia homes.
A small leak does not always remain a small problem.
Repeated water exposure can deteriorate wood framing, weaken joist ends, damage masonry and mortar, and contribute to deterioration within basement and foundation walls.
During existing-condition surveys, we commonly document water staining, damp basement conditions, masonry discoloration, deteriorated wall surfaces, and moisture-related deterioration of wood elements.
This is why simply repairing the visible finish is not enough. If water has been entering the building for an extended period, the structure behind that finish may also need to be evaluated.
7. Basement and Foundation Deterioration
Basements often tell us a lot about the history of a Philadelphia rowhome.
We commonly see aging masonry foundation walls, cracking, deteriorated mortar or parging, moisture intrusion, deteriorated basement slabs, previous structural repairs, and alterations associated with plumbing or renovation work.
Foundation conditions become particularly important when a renovation involves lowering a basement. The city has recently implemented new requirements when basement work is taking place.
Excavating below an existing foundation or party wall can affect the support of both the project property and the neighboring home. Philadelphia requires permits for basement excavation, and certain projects involving excavation or party-wall modifications trigger additional requirements intended to protect adjacent properties.
8. Problems Around Window and Door Openings
Openings interrupt masonry walls, which means the structure above them has to be supported.
In Philadelphia rowhomes, we frequently see cracking, deteriorated masonry, previous infill, patched openings, or altered framing around windows and doors.
Renovations can make this more complicated when homeowners want to enlarge a window, create a new door, or reconfigure the rear of the house.
These changes may require new lintels, headers, or framing to properly carry the structure above the opening.
9. Roof and Rear Wall Deterioration
The rear of a rowhome often shows some of the clearest signs of long-term exposure. This intensifies when the rear of the house has a classic Philly “shed” - the style of addition that is added on to the rear often housing a small kitchen or extra storage.
Weathered brick, deteriorated mortar, patched masonry, staining, deteriorated trim or cornices, and previous repairs are all conditions we regularly document.
Roof leaks are particularly important because water can travel beyond the visible leak location and affect roof framing, ceiling joists, walls, and connections below.
Philadelphia's Rowhouse Manual identifies the roof as one of the most vulnerable portions of the house and recommends investigating the framing when prolonged leakage or neglect may have caused deterioration.
Why Pre-Construction Documentation Matters
The goal of a pre-construction survey is not to label every crack or imperfection as a structural failure.
It is to understand what is there before construction begins.
Philadelphia rowhomes are connected buildings. Shared party walls, adjoining foundations, joists bearing in masonry, connected roof conditions, and decades of previous alterations mean that work occurring at one property can sometimes affect another.
A pre-construction survey creates a photographic and written baseline of important existing conditions before work starts. Monitoring can then focus on those areas during construction and identify meaningful changes, such as new cracking, widening cracks, movement, deformation, or bulging, if they occur.
Philadelphia's current Protection of Property requirements recognize this relationship. Certain work affecting party walls or neighboring structures can require documentation such as pre-construction surveys and monitoring plans.
The Bottom Line
Cracked masonry, deteriorated joists, water staining, patched walls, or uneven framing do not automatically mean that a Philadelphia rowhome is unsafe.
They do tell part of the building's story.
Many Philadelphia rowhomes have been standing for well over a century and have gone through generations of repairs, additions, removals, and renovations. Understanding those existing conditions before starting new work makes it easier to determine what can remain, what needs attention, and where additional structural investigation may be necessary.
At Jane Draws Plans, we believe good renovations start with understanding the building you already have, not just designing the one you want to create.
