Architect vs. Design-Build for an ADU.

An ADU needs two jobs done: drawing it and building it. You can hire one firm to do both, which is usually called design-build. Or you can hire a designer or architect for the plans and a separate contractor for construction, often called design-bid-build. This guide explains the difference, who has to be licensed, and what to ask. We do not recommend a model or any company.

LA ADU Guide is an information site. We do not offer design, building or financing. See also hiring an ADU builder.

Who can draw ADU plans in California?

Not everyone who draws plans is an architect. The law is specific.

• Using the title. Under Business and Professions Code section 5536, a person not licensed as an architect may not "use any term confusingly similar to the word architect," or advertise as "an architectural designer." Unlicensed people also may not use a stamp or seal that implies state licensure.
• Who may prepare plans. Under section 5537(a), the architect chapter does not bar anyone from preparing plans for "single-family dwellings of woodframe construction not more than two stories and basement in height," small multi-unit woodframe buildings of up to four units, and garages and other appurtenant structures with the same height limits.
• The catch. The exemption applies unless a portion departs from "substantial compliance with conventional woodframe framing requirements." Then, under section 5537(b), the building official "shall require the preparation of plans" for that portion by a licensed architect or registered engineer.

So a simple wood-frame ADU may be drawn by a non-architect designer in many cases. Whether your ADU falls inside the exemption is a question for the building department. A tall, hillside or steel-framed project often needs an engineer anyway. We could not confirm how every agency applies section 5537 to ADUs.

What are the roles?

We list these as roles. Look up each license on the state board's own site.

How each model works

Separate designer, then contractor

You sign one contract for plans and another for construction. You can collect bids from several contractors on the same drawings. The designer works for you. Many owners like that the bids are comparable because they are for the same plan set. The downside is more coordination and more contracts to manage, and a contractor may find problems the drawings did not.

Design-build

One company handles design and construction under one contract or two linked ones. It can reduce handoffs and answer the question "can this actually be built" early. The downside is that you may have less independent check on the price, and you may not have a competing bid. Ask whether the design belongs to you if you leave. The point in section 5536 is also worth remembering: a design-build company that is not a licensed architect cannot call someone an architect.

Pre-approved plans

A third path is to start from a design already approved by the city. LADBS says its Standard Plan Program makes permits "issued more quickly," but the department still checks site fit. You still need a builder. See prefab and pre-approved plans.

Questions to ask any firm

• [ ] What license do you hold, and what is the number? Check it on the state board's site.
• [ ] Who prepares the plans, and what is that person's license or exemption?
• [ ] Is a structural engineer included, and are soils or surveys extra?
• [ ] Do I own the plans, and can I take them to another contractor?
• [ ] How many correction rounds with the city are included in the plan fee?
• [ ] What is the fixed price, and what is allowance or estimate?
• [ ] Who pays if the city requires a change after approval?
• [ ] Who pulls the permit, and who attends inspections?

Payment cautions

California law limits some deposits for home improvement contracts. Our builder guide covers CSLB checks and payment cautions. In general, do not pay for plans, permits or construction in a way that is not tied to the written contract and verified work. Ask your building department what a permit costs, instead of relying on a contractor's quote alone.

Plan changes during the build

LADBS says that if you "vary from your plan specifications during construction, re-approval of the plan is required." Under design-build, ask how change orders and plan revisions are priced, and who files them with the city.

Which one fits?

There is no source that says one model is cheaper or faster in Los Angeles, so we do not claim that. Think about what you value:

• You want several bids on the same plans: separate designer.
• You want one point of responsibility: design-build, with a clear contract.
• You want the fastest paperwork and are fine with a catalog design: pre-approved plans plus a builder.

Get the scope in writing before you choose, then compare quotes with the same line items. See ADU cost in Los Angeles and the permit process. More in the hiring hub. This page is general information, not legal advice.