About Us

Custom Design, Design Build – General Contractor

Flagg Coastal Homes is a licensed California Contractor, based in Coronado. It was founded  in 2007 to complement Flagship Properties development and brokerage activities. Flagg Coastal Homes and Flagg Design Studios provides  design, design/build and general contractor services for custom homes in Coronado, San Diego, Point Loma, Del Mar, Encinitas and North County.

Flagship Properties is a privately held real estate development and brokerage company located in Coronado California. Founded in 1975, the company has developed, marketed and sold quality residential and office building developments throughout Southern California. Since 1998, Flagship has specialized in “Coastal Homes” primarily in Coronado.

John O’Brien – Founder

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John O’Brien founded FLAGG COASTAL HOMES as a Design Build Custom Homebuilder in response to the demand for nautically inspired homes in the resort town of Coronado, California. John is a U.S. Naval Academy graduate, former Naval Officer (PT-Boat skipper, PTF-22) and a 37-year veteran of Southern California Real Estate Development, Brokerage and Construction. Most recently, this small cadre of experienced and talented building professionals has successfully developed and sold 60 homes in Coronado in a 18-year span.

Carrie O’Brien – Co-Founder and Principal, Flagship Properties

Carrie O’Brien

Carrie began her real estate career in 2001, initially to support the sales efforts of the development activities of Flagship Properties. From that start, Carrie has built a the highest quality boutique agency in Coronado and she consistently ranks in the top 5 sales brokers on the island. Flagship has closed annual sales of approximately $30 million per year for the last 3 years. Of particular note, Flagg and Flagship enjoy “Market Share” on Coronado’s premier waterfront properties, both bayfront and bayview properties on Coronado’s First Street and oceanfront homes on Ocean Boulevard and Ocean Drive. Carrie is a Stanford graduate with an MBA from UCLA and a Masters in Psychology from Fuller Seminary.

Mark Blore – Co-Founder Building Partner

Mark Blore

Mark Blore joined the Coronado team in 2004. He is a licensed California contractor, and partner in FLAGG Inc. Mark is a former U.S.Navy Seal as well as a Coronado resident. His firm (BSC Inc.) is registered as a Disabled Veteran-Owned Small Business. When he is not building, he is training and competing as an endurance athlete. In 2016, Mark completed the Double Anvill, which is a 5X Ironman.

Our Partners and Staff

Mark Toughest Mudder

At Flagg Coastal Homes, We Do Work.


Dorian Lytle – In-House Designer

Dorian Lytle

Dorian Lytle heads up the Design/Build division Flagg Design Studios. Dorian received his undergraduate degree in Finance from Northeastern University and his graduate degree in Architecture from The Newschool of Architecture and Design in San Diego. Dorian was both the class Valedictorian and also received AIA’s Henry Adams Medal for excellence. Dorian’s passion for design started in Connecticut where as a young man, he worked for Ireland Architecture, drafting beach homes and coastal community projects. That experience allowed Dorian to draw upon the design aesthetics of the coastal Northeast that has translated so successfully to the resort community of Coronado. Regardless of style, location, or size, his design goal remains the same: create a family heirloom for generations to come.

Martin Brown – Project Manager and Contractor

Martin Brown

Martin Brown has been a member of the Flagg team since 2003. He is also a licensed contractor and a first generation American from the Island Nation of St. Lucia. He provides Project Management, Budgeting, and Scheduling services for FLAGG Inc. He operates under the name of St. Lucia Builders.