A builder’s discipline. An owner’s perspective.
Seamline Pacific Builders is a cost-certain, schedule-driven construction firm: general contracting, construction management and owner representation for owners and developers who value clarity, accountability and disciplined execution.
Leadership

Ryan Dumoulin
President

Bill Lee
Project Executive

Quentin Johns
Chief Financial Officer
What owners say
“I have known Ryan Dumoulin for more than ten years, and he is, without question, one of the most capable construction professionals I have had the privilege of working with. Most recently, we partnered on a large public works project for the City of Los Angeles in downtown LA, a job with real complexity, many stakeholders, and no room for error. Ryan ran it beautifully. From day one, the project was completely organized. The contracts were clear, thorough, and well written, which set expectations up front and kept every party aligned throughout. Subcontractors and vendors were paid on time, every time, and that kind of discipline builds trust and keeps a job moving. Ryan stayed on top of every detail and consistently anticipated problems before they became issues. The project was a complete success, and that success is a direct result of Ryan’s expertise, leadership, and integrity. He doesn’t just manage a project; he owns it. I recommend Ryan and Seamline Pacific Builders without reservation to any owner looking for a builder they can count on.”
Specialized expertise
Healthcare and medical
Occupied hospitals, correctional-medical and treatment facilities where infection control, life-safety and 24/7 uptime are non-negotiable.
cGMP, pharma and biotech
Cleanrooms, controlled environments and validation-ready manufacturing built to exacting regulatory standards.
High-tech and laboratories
Advanced facilities and lab build-outs demanding precision, cleanliness and specialized MEP systems.
Central plants and mechanical
Central chilled-water plants, thermal energy storage (TES) and large-scale HVAC modernization.
Plumbing and process piping
Building, process and life-safety piping executed in critical, occupied environments.
Large-scale multifamily
Ground-up multifamily at scale.
Markets we serve
Commercial interiors and TI. Multifamily and mixed-use. Higher education, K-12 and campus. Healthcare, civic, correctional and aviation. Industrial facilities, distribution and logistics.
Prior leadership experience
Projects Ryan Dumoulin led in senior roles at previous firms. These are individual credentials of key personnel, not Seamline Pacific Builders, Inc. company past performance.
| Project | Type | Location | Ryan’s role |
|---|---|---|---|
| Sunset + Vine Tower | High-Rise / Mixed-Use | Hollywood, CA | Project Executive |
| USC Galen Center | Sports / Arena | Los Angeles, CA | Project Executive |
| 5600 Wilshire | Multifamily | Los Angeles, CA | Project Manager |
| NRDC — Robert Redford Building | Commercial | Santa Monica, CA | Project Manager |
| Doheny Eye Institute | Healthcare / Medical | Pasadena, CA | Project Executive - Mechanical Contractor |
| Kaiser Permanente South Bay Medical Center | Healthcare / Medical | Santa Ana, CA | Project Management |
| EVOQ Properties Offices | Commercial | Los Angeles, CA | Project Executive |
| Santa Monica College — AET Campus | Higher Education | Santa Monica, CA | Project Executive - Mechanical Contractor |
| LAX — Security Systems Integration | Aviation | Los Angeles, CA | Project Management |
| CSU Long Beach — Central Plant | Higher Education | Long Beach, CA | Project Executive - Mechanical Contractor |
| CSU Dominguez Hills — Science & Innovation Building | Higher Education | Carson, CA | Project Executive |
| CSU Dominguez Hills — Innovation & Instruction Building | Higher Education | Carson, CA | Project Executive - Mechanical Contractor |
| CSU San Bernardino — Central Plant | Higher Education | San Bernardino, CA | Project Executive - Mechanical Contractor |
| Pierce College — Advanced Automotive Technology Building | Higher Education | Woodland Hills, CA | Project Executive - Mechanical Contractor |
| Pierce College — Central Plant | Higher Education | Woodland Hills, CA | Project Executive - Mechanical Contractor |
| Cabrillo High School (LBUSD) | K-12 Education | Long Beach, CA | Project Management |
| LAUSD — Multiple Projects (13 total) | K-12 Education | Los Angeles, CA | Project Manager |