Accessory dwelling unit companies — Modesto, CA

Last updated: September 24, 2026

What affects the price

Building an ADU is a major project, and the final bill depends on a few key things. Site prep is a big factor; if your land is sloped or needs extensive utility connections, costs go up. The materials you choose—from siding to kitchen finishes—also change the math significantly. Whether you’re building a detached unit or converting an existing garage shifts the permit requirements and structural work needed. We provide exact pricing confirmed free on the call.

About this service

These companies provide end-to-end management for property owners looking to add a secondary unit. They typically offer a mix of design, permitting, and construction management services to streamline the project. You need to hire a company when you want a structured, professional approach to the entire build process rather than managing individual subcontractors yourself. They help ensure your unit is built to code, on time, and aligned with your budget goals.

Frequently asked in Modesto

Also serving nearby: Manteca · Tracy · Stockton · Merced · Antioch

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More on this: HUD ADU resources — ADU policy and financing research.

Service area details

Serving all of Modesto — population 218,915; about 5,049 residents per square mile across 43.4 sq mi. ZIP codes covered include 95350, 95351, 95352, 95353, 95354, 95355, 95356, 95357.

Neighborhoods served in Modesto: Salida, Dry Creek, Orange Blossom, Ripon, Keyes — and every surrounding area.