Attached ADU construction in Costa Mesa.

What to bring into the first discussion.

Start where the new unit meets the house. The design team needs to understand foundations, floor elevations, walls, rooflines, windows, drainage, and the existing rooms affected by the addition.

Look closely at the existing conditions.

Follow plumbing, electrical, heating, cooling, and ventilation through both sides of the project. A convenient route on a sketch can require meaningful work in an occupied room, attic, crawlspace, slab, or finished yard.

Connect the decision to the full scope.

Plan construction around the people who remain in the home. Dust separation, temporary walls, safe entries, service interruptions, security, work hours, and restoration should be part of the written scope.

Use current sources and responsible professionals.

Privacy depends on entry placement, windows, sound control, laundry, outdoor circulation, and the daily routines of both households. Test those relationships before the addition outline becomes fixed.

Read the related Costa Mesa ADU services, cost guide, and permit guide for the construction context.

Choose a practical next step.

Compare an attached addition with a detached ADU, a garage conversion, and a JADU using the same priorities. The smallest footprint is not always the least disruptive project.

Return to Costa Mesa ADU Contractor or call (949) 503-8004 when you are ready to discuss the property.