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Marshall DenneheyShare Holder
Stuart H. Sostmann
Pro

Stuart H. Sostmann

4.6
9 reviews

501 Grant Street, Suite 700, Pittsburgh, PA 15219

Construction Injury Litigation, Product Liability, Property Litigation and 8 more

About Stuart H. Sostmann

With over two decades of experience as a litigator, Stuart concentrates his practice in the area of commercial general liability. He routinely handles high exposure matters in the fields of product liability, premises liability, auto liability, construction litigation, marine liability, dram shop and commercial litigation. This includes cases involving personal injuries and property damage claims.

As the Managing Attorney of the firm's third-largest office, Stuart oversees the daily operations, including the supervision of 75 employees. In addition to his managerial duties, Stuart serves as the Casualty Supervisor, where he ensures that all client matters are handled promptly, professionally, and effectively by the team of attorneys.

In his career, Stuart has represented manufacturers, suppliers and retailers in product liability matters, including electronics, medical equipment, food products, appliances, farm equipment, plumbing equipment, power tools, toys and sports and recreational equipment. He frequently represents property owners, retailers, pharmacies, general contractors, subcontractors and utilities in premises liability litigation. He has tried numerous cases to verdict in counties throughout Western Pennsylvania.

A significant portion of Stuart’s practice has been devoted to construction litigation. These cases are highly complex and require deep industry knowledge and experience. Stuart has handled a wide range of construction injury and defect cases, representing contractors, subcontractors, material suppliers, engineers, architects, and other construction professionals throughout Pennsylvania. His experience includes defending against claims involving construction defects such as water intrusion from faulty roofing or window and door seals, cracked foundations or improper waterproofing, structural and design issues, mold intrusion, drywall defects, and soil subsidence, heaving, or movement.

Stuart attended the University of Pittsburgh graduating with a B.A. in Political Science. He then attended the University of Pittsburgh School of Law where he participated in the Appellate Moot Court Program, Student Bar Association and the Health Law Certificate Program. He obtained his juris doctor from the University of Pittsburgh School of Law.

Stuart currently serves on the Marshall Dennehey Diversity, Equity and Inclusion Committee working to improve the recruitment, retention and advancement of diverse attorneys and professionals. He is the former President of the Pennsylvania Defense Institute, an organization of civil defense attorneys, executives of insurance companies and self-insured corporations. Stuart is also a member of the Allegheny County Bar Association and the Academy of Trial Lawyers of Allegheny County. Among his many honors, he is Rated AV Preeminent by LexisNexis Martindale-Hubbell and is recognized among the Best Lawyers in America for his work in product liability litigation. Stuart is additionally recognized as Pennsylvania Super Lawyer.

Honors & awards

AV Preeminent by Martindale-Hubbell

The Best Lawyers in America, 'Lawyer of the Year,' Pittsburgh, Product Liability Litigation - Defendants
2026

The Best Lawyers in America, Product Liability Litigation - Defendants
2022-2026

Pennsylvania Super Lawyers
2018-2022; 2025

Year joined

1998

Results

Defense Verdict Following Jury Trial in Slip and Fall Case in the Court of Common Pleas of Allegheny County.

Premises & Retail Liability
February 6, 2024

The plaintiff slipped in the lobby of a commercial building and claimed a serious and ongoing injury to her right shoulder. She alleged she fell due to a wet floor caused by the facilities management’s cleaning process and the lack of sufficient visible wet floor caution signs. The plaintiff underwent two surgeries, claimed ongoing pain and suffering, and sought $500,000 prior to trial.

Defense Verdict Secured in Slip-and-Fall Jury Trial

Premises & Retail Liability
February 6, 2024

We obtained a defense verdict following a three-day jury trial in a slip-and-fall injury case in the Court of Common Pleas of Allegheny County. The plaintiff slipped in the allegedly wet lobby of a commercial building and claimed a serious and ongoing injury to her right shoulder. Problematic for our case was the lack of a surveillance video of the incident, photographs of the lobby contemporaneous to the incident, or an incident report.

Marshall Dennehey Successfully Represents Client in Multi-Million Dollar Chemical Spill Case

Property Litigation
October 21, 2021

In a lawsuit seeking $279 million in alleged property damages, Marshall Dennehey attorneys successfully defended their client, a subcontractor of a railroad repair shop, against any and all liability.

Thought Leadership

98 Marshall Dennehey Attorneys Recognized in the 2026 Editions of The Best Lawyers in America and the Best Lawyers: Ones to Watch in America

August 20, 2025
Marshall Dennehey is proud to highlight the firm’s 98 attorneys who have been recognized in the 2026 editions of The Best Lawyers in America and the Best Lawyers: Ones to Watch in America. Less than 6% of all practicing lawyers in the U.S.

Marshall Dennehey Announces 2025 Pennsylvania Super Lawyers and Rising Stars

May 22, 2025
Thirty-three attorneys across Marshall Dennehey's five Pennsylvania offices have been selected to the 2025 edition of Pennsylvania Super Lawyers magazine.

How I Made Office Managing Partner: 'Stay True to Yourself, and Things Will Work Out to Your Benefit,' Says Stuart Sostmann of Marshall Dennehey

Pittsburgh
January 3, 2025

Stuart H. Sostmann Named Managing Attorney of Marshall Dennehey’s Pittsburgh Office

September 3, 2024
Stuart H.

On the Pulse...Construction Injury Litigation Practice Group

Philadelphia - Headquarters
Pittsburgh
Construction Injury Litigation
December 1, 2023
Recent data released from the United States Bureau of Labor Statistics reveals that construction laborers accounted for 11.9% of all reported fatal falls, slips, or trips in 2020 across all occupations. Defense Digest, Vol. 29, No.

Classes/Seminars Taught

AI in the Legal Profession, Marshall Dennehey Client Presentation, September 2024

Civil Litigation State of Affairs - The Impact of COVID-19 in Pennsylvania and New Jersey & What’s Next , Marshall Dennehey Client Webinar, May, 2021

An Overview of Construction Defect Litigation in Pennsylvania, Nationwide Insurance Company, December 16, 2014

Commercial Defense Practice in New York, New Jersey & Pennsylvania, Nationwide Insurance Company, December 5, 2014

Brief Overview of Pennsylvania Contractual Indemnity and Additional Insured Issues, Nationwide Insurance Company, April 2012

Discoverability and Proper Use of Claim Notes, Berkley Mid-Atlantic, October 2011

Media Commentary

'How I Made Office Managing Partner: 'Stay True to Yourself, and Things Will Work Out to Your Benefit,' Says Stuart Sostmann of Marshall Dennehey,' Law.com, January 3, 2025

 

Stuart H. Sostmann (Pittsburgh, Pennsylvania) View website

Awards

AV Preeminent Peer Rated
This elite award is granted to attorneys who have been recognized by their peers for their very high ethical standards, with an average peer review score of 4.5 or higher.
Martindale-Hubbell Peer AV

Client Champion Awards

Client Champion awards recognize those attorneys who excel at service as affirmed by their clients. The awards, based on the quantity and quality of an attorney’s Martindale-Hubbell client reviews, demonstrate an ongoing commitment to delivering excellent client service. Award recipients stand out from their peers with a platinum, gold or silver icon.

Champion Badge Silver

At least three reviews and a score of 4.0 or higher.

Champion Badge Gold

At least six reviews and a score of 4.2 or higher.

Champion Badge Platinum

At least ten reviews and a score of 4.5 or higher.

Martindale Peer Awards

A lawyer who receives a minimum threshold of qualifying responses from fellow attorneys can qualify for one of three prestigious Martindale-Hubbell Peer Review Ratings:

Martindale-Hubbell Peer AV Preeminent Rating

AV Preeminent®: The highest peer rating standard. This rating signifies a large number of the lawyer’s peers rank him or her at the highest level of professional excellence for their legal knowledge, communication skills and ethical standards.

Stuart H. Sostmann got this award in 2021

Martindale-Hubbell Peer Distinguished Rating

Distinguished: An excellent rating for a lawyer with some experience. This rating indicates the attorney is widely respected by their peers for high professional achievement and ethical standards.

Martindale-Hubbell Peer Notable Rating

Notable: This rating indicates that the lawyer has been recognized by a large number of their peers for strong ethical standards.

Avvo Awards

Avvo Top Contributor

Avvo Top Contributor: The Avvo Top Contributor Award is granted to attorneys who have earned significant contribution points in a given year on our sister site, Avvo.com. Contribution points are earned by answering questions in Q&A, publishing Legal Guides, and other useful contributions to the Avvo community.

Avvo Client Choice

Avvo Client’s Choice: The Avvo Client's Choice Award Badge is granted to attorneys with a significant number of 4+ star reviews in a given year.

Reviews for Stuart H. Sostmann

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Overall Rating
4.6
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9
Lawyers.com
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4.6
Martindale
9
Avvo
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Services

Areas of Law

  • Commercial Litigation
  • Other 10
    • Construction Injury Litigation
    • Product Liability
    • Property Litigation
    • Automobile Liability
    • Architectural, Engineering and Construction Defect Litigation
    • Hospitality and Liquor Liability
    • Premises and Retail Liability
    • Catastrophic Claims Litigation
    • Environmental & Toxic Tort Litigation
    • General Liability

Practice Details

  • Firm Information
    Position
    Shareholder
    Firm Name
    Marshall Dennehey
  • Representative Cases & Transactions
    Cases
    Significant Representative Matters: Obtained a defense verdict following a three-day jury trial in a slip
    fall injury case. The plaintiff slipped in the lobby of a commercial building
    claimed a serious
    ongoing injury to her right shoulder. Plaintiff alleged she fell due to a wet floor caused by the facilities management's cleaning process
    the lack of sufficient visible wet floor caution signs. Plaintiff underwent two surgeries, claimed ongoing pain
    suffering,
    sought $500,000 prior to trial. We represented the building ownership
    the facilities management company. Problematic for the defense was the lack of a surveillance video of the incident, photographs of the lobby contemporaneous to the incident, or an incident report. Despite this, we persuaded the jury to find for the Defense by establishing a consistent
    credible history of habitual practice in the placement of wet floor signs across the lobby in highly visible areas. We also won the credibility battle through our well-prepared witnesses. Although faced with a sympathetic plaintiff with a substantiated history of medical treatment, we succeeded by presenting the case using 'old school' personal injury defense tactics that were necessary due to the lack of video, photographs,
    documentation.
    Successfully argued a precedent-setting case in the Pennsylvania Superior Court where a waiver of subrogation clause in a construction contract was applied to building damages caused by a windstorm three years after the project was completed.
    Successfully defended a product installer at trial in a single vehicle accident, where the placement of the product in the vehicle was claimed to be the cause of the crash at high speed. A defense verdict was obtained after a 5 day jury trial where the dem
    was $800,000 prior to trial.
    Published Works: 'Yes! Waivers of Liability for Recreational Activities Are Still Effective in Pennsylvania,' Defense Digest, Vol. 23, No. 1, March 2017
    'Timing Is Everything, Even for Bad Faith Claims,' Defense Digest, Vol. 6, No. 1, February 2000

Experience

  • Bar Admission & Memberships
    Admissions
    1999, Pennsylvania
    2023, Supreme Court of the United States
    Memberships

    Associations & memberships

    Allegheny County Bar Association
    American Bar Association
    Pennsylvania Defense Institute, President 2022-2023
    Executive VP of Operations 2021-2022
    Executive VP of Programming 2020-2021

  • Education & Certifications
    Law School
    University of Pittsburgh School of Law, Pittsburgh, Pennsylvania
    J.D.
    1999 CALI Future Excellence Award in Federal Income Taxation
    Other Education
    University of Pittsburgh, Pittsburgh, Pennsylvania
    Class of 1996
    B.A.
    Political Science

    University of Pittsburgh, Pittsburgh, Pennsylvania
    Class of 1996
    B.A.
    cum laude

Contact Stuart H. Sostmann

Share Holder at Marshall Dennehey
4.6
9 reviews

Union Trust Building, 501 Grant Street, Suite 700Pittsburgh, PA 15219U.S.A.

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Fax: (412) 803-1188

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Attorneys FAQs

  • What year was this attorney first admitted to the bar?
    Stuart H. Sostmann was admitted in 1999 to the State of Pennsylvania.
  • Is this attorney Martindale-Hubbell Peer Review rated?
    Yes, Stuart H. Sostmann has a 4.6 Peer Rating from Martindale-Hubbell.
  • What law school did this attorney attend?
    Stuart H. Sostmann attended University of Pittsburgh School of Law, Pittsburgh, Pennsylvania.

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