Construction That Impacts an Adjacent Property: What Philadelphia’s New L&I Requirements Mean for Designers, Contractors, and Neighbors
Philadelphia is a city built wall-to-wall. With roughly 60% of its housing stock made up of rowhouses, construction rarely happens in isolation. Most projects, whether new construction, demolition, or basement dig-outs, interact directly with neighboring buildings. Over the past decade, several high-profile collapses and structural failures have demonstrated just how vulnerable the shared urban fabric can be.
In response, the City of Philadelphia has implemented a series of legislative and procedural changes aimed at proactively protecting adjacent and adjoining properties. A recent L&I webinar introduced both the existing safeguards and new 2026 requirements that will affect permitting, documentation, inspections, and insurance.
This blog post walks through the major takeaways and what they mean in practice.
Why These Rules Exist
The International Building Code was not written with dense “rowhouse cities” in mind. Philadelphia’s building stock frequently shares:
Party walls
Chimneys and flues
Tunnel alleys
Foundations and footings
Rooflines and parapets
Failures at any one site can quickly become neighborhood emergencies. The City’s goal is to shift from a reactive model (responding after damage occurs) to a preventative culture, where risks are identified, documented, and monitored before construction begins.
The 2023 Legislative Foundation
Two key ordinances took effect January 1, 2023:
1. Excavation Permits (Bill No. 210389)
Separate excavation permit required for work more than 5 feet below adjacent grade.
Includes many basement dig-outs.
2. Excavation Contractor Licensing (Bill No. 210389)
Specialized license required.
Additional training, insurance, bonding, and safety personnel.
3. Protection of Property (Bill No. 220008)
For certain scopes of work that may impact neighboring structures, projects must include:
Pre-Construction Surveys (PCS)
Monitoring Plans
Notifications to Adjacent Property Owners
These three components now form the backbone of adjacent-property protection in Philadelphia.
Pre-Construction Surveys (PCS)
A PCS is a licensed professional engineer’s assessment of existing conditions of adjacent and adjoining buildings.
What Must Be Surveyed
All adjoining and adjacent buildings
Historic structures on abutting lots within 90 feet
Rear properties within excavation impact zones
What Must Be Documented
Height, stories, construction type, exterior wall type
Existing cracks, movement, deflection, deterioration
Size, length, and severity of each distress condition
Elements that may be impacted by construction or demolition
Visible chimneys, parapets, skylights if the new building rises above neighboring roofs
Photo Requirements
At minimum:
Elevation views of facades visible from the public right-of-way
Unobstructed images showing facade conditions
Purpose of the PCS
The survey is not just a record; it must identify:
Conditions requiring monitoring
Temporary protections (bracing, roof coverings, fall protection)
Permanent alterations are needed to mitigate code violations caused by new work
All intended resolutions must be shown in construction documents.
Monitoring Plans
Monitoring Plans translate PCS findings into actionable inspection protocols.
Engineer Responsibilities
The engineer determines:
Locations of monitored conditions
Inspection frequency
Required instruments (crack gauges, inclinometers, etc.)
Acceptable tolerances and thresholds
Actions if thresholds are exceeded
Key Rules
Monitoring cannot be waived.
At minimum, general monitoring must be identified.
Monitoring must be performed by a Special Inspector approved for Structural Stability of Existing Buildings.
Reduced inspections require an amended permit.
Coordination with Special Inspections Schedule
The Monitoring Plan must align with the Statement of Special Inspections.
The same Special Inspection Agency must appear on both documents.
Notification to Adjacent Property Owners
Written notification is mandatory and must be provided:
At the initial permit submission
At least 10 days before work begins
(Unsafe or imminently dangerous buildings are exempt from timing minimums.)
Notice Must Include
Description of work
Plans showing potential impacts
Project schedule
Pre-construction survey
Temporary and permanent protections
Prescribed monitoring
Contractor Certificate of Insurance
Project contact information
If signatures cannot be obtained, certified mail receipts are required.
Owners must also provide updated notices if project conditions change.
L&I will independently notify adjacent owners if information is missing or insufficient.
Exposed Party Walls During Demolition
If demolition exposes a party wall:
It must receive exterior wall coverings compliant with IBC Chapter 14.
Temporary weather protection allowed for maximum 60 days.
Permanent exterior wall covering must be in the demolition permit scope or under a separate permit.
Exposed party walls left uncovered after 60 days constitute a violation.
Backfilling After Demolition
When no new construction is contemplated:
Vacant lots must be backfilled and graded per approved documents.
Demolition permits cannot remain open indefinitely.
Within 30 days of building removal.
Site must be backfilled, or
New construction permit must be issued.
If demolition exposes foundations or includes excavation within 10 feet of an adjacent structure, monitoring must begin immediately.
Excavations
When an Excavation Permit Is Required
Any excavation deeper than 5 feet below adjacent grade.
Permit Sequencing
Excavation permit must be approved before a building permit is issued.
Combination building + excavation permits may be submitted through eCLIPSE.
Excavation Contractor License Requirements
Commercial Activity License + BIRT ID
Insurance:
$2M general liability
$300k auto liability
Workers’ comp with specific minimums
Dedicated Site Safety Manager
OSHA 30 + OSHA 3015 training
$100k license bond
Soils Investigation Report
Must identify:
Adjacent footing depths
Interior elevations of neighboring structures
Exploratory test pits
Archived records (cannot be solely relied upon)
Must comply with Code Bulletin B-9906-R7.
Plan Submission
Support of excavation must be engineered unless all of the following are met:
≤12 ft deep
≤15 ft wide
10 ft from adjacent building
10 ft from ROW or transit structures
Designed per OSHA prescriptive standards
Case Study: Why Safeguards Matter
A shared tunnel alley collapse caused partial failure of an adjacent rowhouse even after 2023 safeguards were in place. Although cracks were documented in the PCS, periodic inspections proved insufficient.
This incident directly motivated the City to introduce additional layers of review, standardized forms, and mandatory coordination meetings.
New Forms (Effective April 1, 2026)
Pre-Construction Survey Summary Form
Supplements full PCS
Completed by licensed PE
One form per affected structure
Seven sections:
Project address
Adjacent property information
Shared elements
Work above roofline
Visible cracks
Pronounced deformations
Misalignment of exterior wall envelope
New Monitoring Plan Form
Replaces prior narrative plans
Requires:
Description
Instrument
Location
Frequency
Alert level
Action level
Required response
New Exemptions (Proposed)
Excavation permit not required for:
Accessory structures for one- or two-family dwellings located >10 ft from adjacent buildings
Sign structures >10 ft from adjacent buildings
Minor work demonstrated to have no potential impact
Underpinning may satisfy support-of-excavation documentation when no other excavation occurs.
New Mandatory Pre-Construction Meeting (Pilot Program)
For residential new construction impacting adjacent property:
Contractor schedules a meeting within two weeks of work
Mandatory attendees:
Contractor
Special Inspector
Department personnel
Non-cooperation is a violation and may result in:
Fines
License action
Stop Work Orders
New Insurance Requirements (January 20, 2026)
Developers and contractors must:
Name adjacent property owners as additional insureds
Upload Certificate of Insurance before permit issuance
Minimum coverage:
$1,000,000 general liability for new construction
$2,000,000 for complete demolition
COI must state: “Covers operations of the named insured.”
Coverage must be maintained for the entire project and provided to neighbors upon request.
What This Means for Project Teams
Designers, engineers, and contractors must now:
Treat adjacent buildings as part of the project scope
Budget time and fees for PCS, monitoring, and coordination
Coordinate early with special inspectors
Educate clients on notification and insurance obligations
Expect stricter review and enforcement
For firms working in Philadelphia, mastering these requirements is no longer optional, it is fundamental to practicing responsibly in a dense urban context.
Final Thought
Philadelphia is positioning itself as a national leader in adjacent-property protection. While the added documentation and coordination increase upfront effort, they dramatically reduce the likelihood of catastrophic failures, lawsuits, and displacement of residents.
Protecting neighbors is not a bureaucratic hurdle, it is a core design responsibility.
To read about all details in more depth please click on this link.
Construction That Impacts an Adjacent Property (L&I resource page)
