Armstrong Builders Inc. is a licensed ADU contractor in Greater San Diego specializing in accessory dwelling units, granny flats, and casitas. They offer full design-build services, custom floor plans, early price locks, and in-house teams.

Armstrong Builders Inc. – ADU Contractor in San Diego, CA

About Armstrong Builders Inc.

Armstrong Builders Inc. — ADU Contractors in the Greater San Diego Area

Armstrong Builders Inc. is a licensed general contractor that focuses on the design and construction of accessory dwelling units (ADUs) in the Greater San Diego region. These structures go by many names — granny flats, casitas, guest houses, in-law suites — but the scope of work remains consistent: managing the full process from initial concept through to a completed build.

As an experienced ADU builder, Armstrong Builders Inc. takes on responsibility for each phase of the project. This includes initial planning and budgeting, feasibility assessment, design, plan check, permitting, and construction. By handling all of these steps in-house, they aim to provide clients with a clear and accountable process throughout the life of the project.

Design-Build Services for Accessory Dwelling Units

Armstrong Builders Inc. works with both standard and custom ADU floor plans, making their services applicable to a range of property types and client needs. Whether the goal is multigenerational living — such as housing an aging parent or adult child — or adding a rental unit as an investment property, their team is structured to handle the project from start to finish.

One practical aspect of their approach is the ability to offer a price lock early in the project, typically within the first few weeks. This is made possible by their integrated design-build model, which allows cost assessments to begin from day one rather than emerging later in the process.

Their team of employees — rather than subcontractors — are involved at each stage, which is intended to maintain consistency and accountability across the board. This structure also means that communication stays within a single team rather than being distributed across multiple independent parties.

Experience in Custom Home Building and ADU Construction

Armstrong Builders Inc. brings over a decade of custom home building experience to their ADU construction work. Their focus has shifted to concentrate specifically on accessory dwelling units, applying that broader construction background to the more specialized requirements of detached ADU building, backyard cottage construction, and related project types.

For property owners in the Greater San Diego area considering an accessory dwelling unit — whether a detached backyard structure, a casita, or an in-law suite — Armstrong Builders Inc. positions itself as a contractor capable of managing the full scope of that work under one roof.

Services

Armstrong Builders Inc. performs the following services

  • Architecture & Design
  • Permit Specialist
  • Construction
  • Feasibility & Site Assessment
  • 3D renderings & floor plans

Armstrong Builders Inc. Reviews

Tommy Tong

2025-05-21
"Initially I hired a different GC and architect to design and build my 17 unit apartment. The design was expensive to build and the GC we used had judgement against him where the lender won't approve our construction loan. We were lucky to have found Tom Armstrong from Armstrong builders to take over our project. Tom is an architect and builder so he quickly made changes to our design to make it more functional, improve the unit mix, while lowering the construction cost. One of the many changes he recommended was using garages instead of carports, while lining up all the structures for support. This has reduced the cost by eliminating the use of expensive steel support while increasing the value of our project by adding 16 garages. Our project started right before COVID hit the first time and during construction we were negatively impacted by the increase of material cost, shortage of available labor, and delays from supply chain issues. Tom helped us jump through every hurdle with his CAN DO and GET IT DONE attitude. At the end we were able to complete the 17 unit and get it rented out right as the interest rate hike began. I have seen many projects paused and failed during that period of time and I am glad we had Tom to get us to the finish line. I am very grateful and he deserves more than the 5 stars review that I can give him. Highly recommended. Will definitely seek his guidance and expertise again for all my future projects!"

jean cantwell

2014-03-24
"In 1997, we met Tom and received a quote to remodel our home. His ideas were much to our liking, and the other bids were not even considered. Rick and crew did a fabulous job...attention to all details.. The remodeled part of the home was a show piece. In 2001, Armstrong was the contractor on five homes in LaJolla. We went out to the job site a number of times, and decided to take one of the homes. We were able to incorporate a number of Tom's ideas into this home as well. Another wonderful home......thanks to Tom, Rick and their crews. Tom was called back, picked his brain again, and used his ideas for an extension of the deck.....again, another successful endeavor. from very happy owners.........ed and jean"

Hillary Bertran-Harris

2014-02-12
"I am the leader at a elementary academy with an emphasis in the performing arts. When my school wanted to add a theatre and stage to its space during the summer of 2013, Armstrong Builders was suggested to conceptualize, facilitate and complete the job. Tom Armstrong presented a number of exciting and prospective options which included a backstage area, storage for large set pieces and two dressing rooms and he was very knowledgeable about building the structure to code with consideration that it would be used by young students. I was thoroughly impressed with Tom's professionalism and the crews' efficiency. Armstrong Builder's agreed to work within my budget and honored my desired timeline. This past fall, I had the opportunity to direct a student play on our brand new stage and the students were so excited! Thanks to Armstrong Builders, they were able to have a real theatre experience and enjoyed every minute of it!"

Caroline Sommer

2014-02-07
"Tom Armstrong of Armstrong Builders Inc has decades of design and building experience. Tom and his staff have created some of the best built, most beautiful new homes and remodels San Diego has ever seen. Tom also has vast coastal development knowledge that allows clients to maximize options for their project, thereby creating a unique design that suits all needs. Whether a single room addition or an entirely new home, clients have been very pleased with Toms designs. I know this because I have worked with Tom for 16 years as his office manager. I have been the recipient of comments and correspondence from his many clients over the years. There has been a great deal of praise for Tom, as well as praise for his experienced building team. Throughout the years, clients have appreciated the personalized attention shown to them and the extra mile Tom has gone to provide the architectural theme desired, value, function and excellent workmanship. Choosing Tom to guide you through the building process, whether large or small, is one of the wisest decisions the clients have ever made."

Papa McCleary

2014-02-05
"I have been very happy with the quality of work done by Armstrong Builders. Tom Armstrong has a very creative and exacting eye for all of the work that he and his crew handle. I like his design style and approach. He usually has fresher and better ideas than I have for how things should look and how to approach the overall design I am a repeat customer and have used Tom for numerous small projects, a remodel of my home, and also the design and construction of several large 4-unit complexes. Rick is meticulous and Tom has "an eye as good as a level to make sure that the work not only is right but looks right as well. Tom seldom is the lowest bidder or highest builder, but his work and follow-through have been excellent. I have always felt that I got everything that I paid for and more. While he seems always to be busy, he gets back to me quickly on any issues that I have."

Specifics

Licensed 10 years in business

Opening hours

Monday 8:00AM - 4:00PM
Tuesday 8:00AM - 4:00PM
Wednesday 8:00AM - 4:00PM
Thursday 8:00AM - 4:00PM
Friday 8:00AM - 4:00PM
Saturday -
Sunday -

Location

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