What to Do About Exterior Wall Failures
Common Problems in Philadelphia Rowhomes - and How to Fix Them
Philadelphia’s housing stock is iconic. From historic brick rowhomes in South Philly to Victorian twins in West Philly, many of the city’s homes were built more than a century ago. While these buildings were constructed with durable materials, time, weather, and moisture can lead to failures in the exterior wall system.
Understanding what these failures look like and how to address them can help homeowners protect their property and prevent costly structural damage.
Below are some of the most common exterior wall failures seen in Philadelphia homes and what can be done to repair them.
1. Deteriorating Mortar Joints
One of the most common problems in Philadelphia masonry homes is deteriorated mortar joints. Mortar naturally weathers faster than brick, meaning it often breaks down first. Once mortar begins to crumble or fall out, water can enter the wall system and cause further deterioration.
What it looks like
Mortar that is powdery, cracked, or missing
Gaps between bricks
Loose or shifting brick units
Why it happens in Philly
Philadelphia’s freeze-thaw cycles and frequent rain accelerate mortar deterioration. Many historic homes also used softer lime mortars that weather over time.
How to fix it
The most common repair is repointing (or tuckpointing). This process removes damaged mortar and replaces it with new mortar that matches the original composition and strength. Repointing restores structural stability and prevents water from penetrating the wall system.
In historic homes, it is especially important that the replacement mortar is compatible with the original brick.
2. Bowing or Bulging Brick Facades
Many Philadelphia rowhouses have a brick facade that is separate from the structural framing behind it. Over time, the connection between the two systems can weaken.
In some cases, the facade begins to bow outward, which can eventually lead to collapse if not repaired. Structural inspections of Philadelphia rowhomes frequently identify buckling brick walls caused by poor lateral attachment between the masonry and floor framing.
What it looks like
Brick wall bulging outward
Windows that appear misaligned or out of plumb
Stair-step cracking around openings
Why it happens
Failed wall ties between brick and framing
Long-term moisture damage
Structural settlement
How to fix it
Solutions often include:
Installing wall anchors or tie-rods to reconnect the brick facade to the building structure
Rebuilding sections of the wall if the bulging is severe
Repairing cracks and repointing mortar joints
In Philadelphia, you can often spot historic star bolts on rowhouses. These metal anchors are commonly used to stabilize aging masonry facades.
3. Moisture Penetration and Water Damage
Water is the biggest enemy of masonry walls. When moisture penetrates a wall system, it can weaken mortar, loosen bricks, and eventually cause structural deterioration.
Signs of moisture problems
Damp spots on interior walls
Mold or mildew growth
White mineral residue on brick (efflorescence)
Peeling paint or damaged plaster inside
Why it happens
Common causes include:
Poor drainage around the home
Missing or blocked gutters
Cracked mortar joints
Improper flashing around windows and doors
How to fix it
Repair strategies usually involve addressing the source of the moisture, not just the visible damage:
Repointing damaged masonry joints
Installing proper flashing around windows and doors
Improving drainage and gutter systems
Applying breathable water-repellent sealers where appropriate
In newer wall assemblies, designers may also incorporate drainage systems like weep holes or rainscreens, which allow water that enters the wall to drain out safely.
4. Spalling Brick
Another common failure in Philadelphia homes is spalling brick, where the face of the brick flakes or breaks apart.
What it looks like
Brick faces crumbling or peeling
Brick pieces falling off
Rough or pitted brick surfaces
Why it happens
Spalling typically occurs when moisture enters the brick and then freezes during winter. As water expands, it causes the outer layer of the brick to break apart.
Philadelphia’s freeze-thaw climate makes this a frequent issue.
How to fix it
Repair options include:
Replacing damaged bricks
Repointing surrounding mortar
Improving drainage to prevent future moisture infiltration
In some cases, full sections of brickwork may need to be rebuilt.
5. Problematic Exterior Coatings
In the mid-20th century, many Philadelphia rowhomes were coated with stucco-like finishes or cement coatings to modernize their appearance. Unfortunately, these materials often trap moisture inside the brick. This issue can also occur when properties are painted with non-breathable or incompatible paints.
When moisture cannot escape, it can lead to cracking, brick deterioration, and hidden structural damage.
What it looks like
Cracked stucco coatings
Bulging areas in exterior finishes
Moisture damage beneath coatings
How to fix it
Solutions may include:
Carefully removing impermeable coatings
Repairing the underlying masonry
Repointing damaged joints
This type of restoration should be handled carefully, especially on historic buildings.
Why Early Repairs Matter
Exterior wall failures rarely happen overnight. Most begin as small issues like hairline cracks, loose mortar, minor water infiltration that worsen over time if ignored.
Early detection and maintenance can prevent major structural repairs and preserve Philadelphia’s historic housing stock.
If you notice cracking, bulging walls, moisture damage, or deteriorating brick, it’s best to consult a qualified contractor or structural professional who understands masonry construction common to Philadelphia rowhomes.
Preserving Philadelphia’s Historic Homes
Philadelphia’s architecture tells the story of the city from 19th-century brick rowhouses to early 20th-century masonry buildings. Maintaining these exterior walls is not just about preventing damage; it’s about preserving the character of the neighborhood.
With regular inspections, proper maintenance, and thoughtful repairs, these buildings can continue to stand strong for another hundred years.
