Serrato Builders is your C-8 licensed ADU foundation and structural concrete contractor in Los Angeles County. With California's ADU laws making it easier than ever to add a detached or attached accessory dwelling unit, the foundation is where it all starts. We pour ADU foundations, structural slabs, stem walls, and reinforced concrete per engineered plans — working with your architect, structural engineer, and city inspectors to get the foundation right the first time. From a simple 400 sq ft garage conversion slab to a full hillside ADU with caissons and grade beams, we handle the concrete so your builder can focus on framing. Whether you're searching "ADU foundation contractor near me" or "structural concrete Los Angeles," we're ready.
The foundation is the single most important part of any ADU build — get it wrong and everything on top of it suffers. We pour ADU foundations per engineered structural plans, with proper rebar, concrete strength, and compaction so your ADU stays level and crack-free for decades.
Full foundation systems for standalone ADUs: excavation, forming, rebar per structural plans, concrete pour, anchor bolts, and stem walls. We handle both slab-on-grade and raised foundations depending on your site conditions and engineer's design. Includes underground plumbing sleeve coordination and termite pretreatment.
Converting a garage to an ADU? We pour new interior slabs inside existing garage shells — including proper vapor barriers, rebar reinforcement, and tie-ins to existing footings. We also handle cutting and patching for new plumbing, trench drains, and step-down entries per code.
Reinforced concrete slabs with integral stem walls for ADUs, room additions, and residential construction. We pour monolithic slab/stem wall combinations per structural drawings, with thickened edges, rebar mats, and anchor bolt placement coordinated with your framing contractor.
ADUs on sloped lots need caissons, grade beams, and retaining walls per geotechnical and structural engineering. We have the heavy-equipment experience and hillside expertise to execute these complex foundations. See our structural hillside page for details.
Before concrete goes down, the site needs to be prepped right. We handle grading, compaction, vapor barriers, underslab drainage, and rough plumbing coordination. Every ADU foundation includes positive drainage away from the structure. See our drainage page.
We pull permits when required and coordinate with city/county building inspectors throughout the foundation phase. Our work passes inspection the first time because we build to the plans — no shortcuts, no substitutions without engineer approval. C-8 licensed, bonded, and insured.
Structural & Geotechnical Plans
We build from your engineer's stamped plans. If you don't have plans yet, we can recommend structural engineers we work with regularly.
Permit Status
We can work with open permits or help you pull new ones through the City of LA, County of LA, or your local building department.
We proudly serve homeowners, builders, and investors throughout Los Angeles County.
Common questions about ADU foundations in Los Angeles
Contact us today for a free estimate. Our team is ready to discuss your project needs and provide expert guidance.