Star Bolts in Philadelphia Row Homes: A Step-by-Step Guide for Homeowners
If you’ve strolled through South Philly, Fishtown, Brewerytown, or other historic Philadelphia neighborhoods, you’ve probably noticed the distinctive star-shaped (or sometimes square, diamond, or round) metal plates on brick facades. These aren’t just charming architectural details — they’re star bolts, also known as structural ties or anchor plates. They play a vital role in stabilizing masonry bearing walls that have begun to bow, bulge, or separate over time.
Philadelphia’s rowhomes, many built between the 1890s and 1930s (and earlier), feature load-bearing brick or fieldstone masonry with wooden floor and roof joists. The front and rear walls are often more vulnerable because they have fewer connections to the rest of the structure compared to the party walls. Over decades, settlement, moisture infiltration, freeze-thaw cycles, aging lime mortar, and sometimes adjacent construction can cause these walls to move outward. Star bolts offer a proven, relatively cost-effective way to tie the masonry back to the interior framing and prevent further movement — without the disruption and expense of rebuilding an entire wall.
Important Note: This is general educational information for Philadelphia-area homeowners. Every home is different. Star bolt work is structural in nature and should only be performed under the direction of a licensed Professional Engineer (P.E.) with stamped drawings, proper City of Philadelphia permits, and experienced contractors. Improper installation can worsen damage or create safety issues. At Axial Force Engineering & Inspection, our licensed P.E.s regularly assess and design solutions for these exact conditions in Philadelphia rowhomes and surrounding areas.
Signs Your Philadelphia Home May Need Star Bolts
Common indicators include:
Visible outward bowing or bulging of the front or rear brick/stone wall (sometimes measured in inches at the center)
Horizontal or stair-step cracks in the masonry, especially near floor or ceiling lines
Doors or windows that stick or no longer close properly
Gaps or separation where walls meet floors, ceilings, or adjacent structures
Sloping floors or noticeable movement when walking in certain areas
Previous water damage, poor drainage, or signs of foundation settlement
If you notice these, start with a professional structural assessment rather than jumping straight to repairs.
Why Start with a Licensed Structural Engineer?
A qualified P.E. experienced in Philadelphia’s building stock will:
Evaluate the extent and cause of movement (not all bowing requires the same fix)
Determine whether star bolts are appropriate or if other solutions (helical ties, steel reinforcement, foundation work, etc.) are better
Design the specific system: rod diameter (commonly ¾" or 1" threaded galvanized or stainless steel), quantity, spacing, and how the interior connection will engage the joists (often with blocking to distribute load across multiple members)
Provide the stamped documents needed for permits
This engineering step protects your home’s long-term safety and helps avoid unnecessary work.
The Step-by-Step Installation Process
Here’s what a typical star bolt project looks like for a Philadelphia rowhome (actual details vary by property and engineer’s design):
1. Assessment, Design & Permitting The engineer completes the site evaluation and prepares drawings/specifications. Permits are submitted to Philadelphia’s Department of Licenses & Inspections (L&I) through the eCLIPSE system. Structural repairs like this generally require a building permit. If the property is in a historic district, the Philadelphia Historical Commission often reviews the visible plates — traditional star designs are usually welcomed as they match the era. Expect plan review, possible comments, and staged inspections.
2. Site Preparation & Safety Setup Crews protect landscaping, neighboring properties, and interior finishes. Exterior access typically involves scaffolding or lifts for safe work at height. Inside, furniture is moved, floors are protected, and sections of drywall, plaster, or ceiling may be opened to reach the joists. Utilities are identified and safeguarded. Dust and debris control is especially important in older Philly homes.
3. Layout & Drilling Precise locations are marked on the exterior to align with interior floor or ceiling joist lines (often near floor levels so the system can engage multiple structural members). Pilot holes are drilled through the masonry, followed by the full-size hole for the tie rod. Care is taken to minimize damage to historic brick or fieldstone and to maintain alignment through the full wall thickness (many Philly walls are double-wythe brick).
4. Installing the Tie Rods & Interior Connections The threaded steel rod is inserted through the wall. On the interior side, it connects to the framing — commonly by passing through added wooden blocking installed between several consecutive joists, or directly through joists with large bearing washers and nuts. This spreads the stabilizing force so the wall is tied back to the building’s internal structure rather than relying on a single point.
5. Securing the Exterior Star Plates On the outside, a large star-shaped (or other decorative) bearing plate is placed against the masonry. A nut is installed and progressively tightened to the engineer-specified tension. This holds the wall in its current position and resists further outward movement. Multiple star bolts are installed in a pattern determined by the engineering design — often several per affected level or concentrated where movement is greatest.
6. Finishing, Cleanup & Final Inspection Disturbed mortar joints are repointed with compatible materials (lime-based mortars are often preferred for historic breathability). Interior openings are repaired and finished. The facade is cleaned. Final L&I or engineer inspection confirms the work meets the approved plans. You’ll receive documentation for your records.
7. Monitoring (Recommended) Periodic checks (photos, crack gauges) over the following months or years help confirm the wall has stabilized.
What Homeowners Can Expect
Timeline: Assessment and design can take 1–3 weeks (or longer depending on complexity). Permitting varies. Installation itself often takes a few days to a week or two for a typical rowhome project.
Disruption: Moderate. Expect scaffolding outside, some interior dust and access limitations while work is underway, and temporary cosmetic repairs inside.
Cost: Varies significantly based on number of bolts, access, whether interior finishes need restoration, and any related work (drainage improvements, repointing, etc.). It is generally far less expensive than rebuilding a wall. Obtain detailed quotes from contractors working with your engineer.
Aesthetics: The star plates become part of your home’s character. Many owners paint them or leave them to weather naturally.
Benefits of Proper Star Bolt Installation
When designed and installed correctly, star bolts can:
Effectively stabilize bowing or bulging masonry walls
Prevent further movement and potential safety issues
Preserve the historic character of Philadelphia rowhomes
Provide a durable, long-lasting solution with proper maintenance
Add value by addressing a visible structural concern before it affects a sale
Maintaining Your Home After Stabilization
Good ongoing maintenance helps protect the investment:
Keep gutters, downspouts, and grading directing water away from the foundation
Address any roof leaks or masonry deterioration promptly
Monitor for new cracks or movement and have them evaluated if they appear
Star bolts are a time-tested solution that has helped keep Philadelphia’s beloved rowhomes standing for generations. They combine practical structural engineering with a distinctive look that fits the city’s architectural heritage.
If you’re noticing signs of wall movement in your Philadelphia-area home, don’t wait for the problem to worsen. A professional structural assessment by a licensed P.E. is the best first step.
Axial Force Engineering & Inspection provides thorough structural evaluations, engineered designs, and guidance through the permitting and repair process for masonry stabilization projects across Philadelphia and surrounding counties. We understand the unique challenges of local rowhomes, fieldstone foundations, and historic construction.
Contact us today to schedule an assessment or learn more about how we can help keep your home safe and stable for years to come.
This content is for informational purposes. Specific recommendations require site-specific engineering evaluation.
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