Cornerstone Builders LLC – ADU Builder Serving the North Olympic Peninsula
Cornerstone Builders LLC is a Sequim-based accessory dwelling unit builder that has been serving Washington State's North Olympic Peninsula for over 40 years. As an experienced ADU contractor, they work with homeowners who need additional space for a variety of purposes — whether that's long-term or short-term rentals, housing a family member or caregiver, or providing a temporary place to live while a primary home is being built.
Operating as a design-build firm, Cornerstone manages every phase of the ADU project in-house, from initial design through to completed construction. This means clients work with a single team throughout the entire process rather than coordinating between separate designers and builders.
What Sets Their ADU Build Process Apart
Cornerstone structures their approach around three key areas that aim to make the ADU build experience manageable and transparent for the homeowner:
- Time and energy savings: As a design-build firm, they handle every step of the ADU design and construction process. Clients are guided through the process from start to finish without having to manage multiple contractors or vendors independently.
- Transparency and peace of mind: Cornerstone provides comprehensive specifications, detailed plans, and scheduled milestone meetings to keep clients informed on budget and scope. They also offer an app that allows clients to track every detail before and during construction — so there are no surprises when the build is complete.
- Thoughtful site planning: Their in-house design team focuses on placement planning to ensure the ADU does not negatively affect the long-term use of the property. This involves a working knowledge of utilities, drainage systems, and cost trade-offs to determine the most practical location for the new structure.
This structured approach is intended to give homeowners a clear picture of what they're getting before construction begins.
The ADU Design-Build Process – Step by Step
Cornerstone follows a three-step process for their ADU projects in Sequim, WA:
- Consultation: The process begins with an initial meeting at the client's property. The Cornerstone team takes time to understand the homeowner's vision and needs before moving forward. They only proceed to the design phase once they are confident they fully understand the project requirements.
- Design and Planning: Whether a client comes with an existing design or is starting from scratch, Cornerstone works to ensure the build is tailored to the individual. They also manage all preconstruction steps, including engineering, permitting, estimating, and construction planning.
- Construction: During the build phase, the team oversees all aspects of construction — including demolition, material ordering, subcontractor scheduling, and inspections — so the homeowner can follow the project's progress without being burdened by day-to-day management.
It's worth noting that Cornerstone holds a Certified Builder designation, which is an elective accreditation that goes beyond standard contractor registration in the State of Washington. This distinction indicates a higher level of professional commitment within the building industry.
For homeowners on Washington's North Olympic Peninsula looking for a reliable ADU builder or accessory dwelling unit builder, Cornerstone Builders LLC offers a well-established, process-driven approach backed by decades of local experience.