Adu building — Cambridge, MA

Last updated: September 24, 2026

What affects the price

Building an ADU is a custom project, so costs vary based on your specific choices. Site conditions are the biggest factor; if your land requires significant grading, utility extensions, or foundation work, those expenses add up quickly. Choosing high-end finishes, custom cabinetry, or complex roof lines will also push the budget higher compared to a standard design. Prefabricated units often offer predictable costs, while custom site-built structures allow for more flexibility but can be harder to estimate upfront. Exact pricing confirmed free on the call.

About this service

ADU building covers the entire process of planning, permitting, and constructing a secondary home on your property. This involves drafting site plans, getting approval from your local planning department, and handling the structural work from foundation to roof. You need this service when you are ready to officially break ground on your project. Costs are driven by the complexity of the design, site preparation, and finish materials. Exact pricing confirmed free on the call.

Frequently asked in Cambridge

Also serving nearby: Newton · Boston · Quincy · Lynn · Brockton

All cities in Massachusetts →

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

Service area details

Serving all of Cambridge — population 118,214; about 18,479 residents per square mile across 6.4 sq mi. ZIP codes covered include 02138, 02139, 02140, 02141, 02142, 02238.

Neighborhoods served in Cambridge: Central Square, Inman Square, Porter Square, Harvard Square, Kendall Square — and every surrounding area.