There are two main ways to take a residential project from an idea to a finished building. In the traditional route, you hire an architect or designer to draw it, then put the drawings out to bid and hire a contractor to build it. In design-build, one company does both under one contract. Neither is right for every project. This note compares how each one runs, where the budget risk sits, and which tends to suit an ADU or an addition.
How each path runs from sketch to keys
Architect, then contractor. You hire a designer, who meets with you, develops the design and produces a full set of drawings. The drawings go to plan check, and the designer answers the corrections. Once you have permit-ready plans, you invite contractors to bid on them. You choose one, sign a separate construction contract, and the build begins. During construction, the designer may stay involved to answer questions or review the work, often for an additional fee.
Design-build. You hire one company. It reviews the site, develops the design with you, prices it as it goes, submits for permits and builds the project. You have one contract and one point of contact from the first meeting to the final inspection.
The main difference is the handoff. In the traditional route, the drawings are finished before the builder sees them. In design-build, the builder is in the room while the drawings are made.
Who carries the budget risk
In the traditional route, the design is usually finished before anyone prices it in detail. If the bids come in higher than expected, you have paid for drawings that may need to be redrawn or reduced. The designer's job is the design, and the contractor's job is to build what is drawn. The gap between the two is yours to manage.
In design-build, cost is part of the design process. Because the same company will build what it draws, it prices choices as they are made and tells you when a feature pushes the budget. That does not remove risk. Unforeseen conditions, such as a garage slab that needs replacing or a sewer line deeper than expected, still happen. But the risk of a design that cannot be built within budget is carried by the company drawing it.
Changes and redesign costs
Changes cost the least on paper and the most once construction has started. In both routes, moving a wall during framing costs far more than moving it in a drawing.
In the traditional route, a change during construction often involves both the designer and the contractor, each with their own fee. A redesign after high bids involves the designer again, and sometimes a second round of plan check. In design-build, a change goes through one company and one change order, though it still costs money and may still need city approval.
Whichever route you choose, insist that every change is priced and approved in writing before the work is done.
Questions to settle on either path
Whichever way you go, a few questions keep the project honest. Who answers the plan check corrections, and is that included in the fee? When does someone put a real number on the design, and what happens if that number is too high? Who is responsible for the utility connections and the site work, which drawings often leave vague? Who schedules the inspections, and who attends them? And when something unexpected turns up below grade, who decides how to handle it and how is it priced?
On the traditional path, some of these answers sit with the designer and some with the contractor, so ask both. On the design-build path, they should all sit with one company, and the contract should say so.
Which suits an ADU or an addition
For a large custom home with a strong architectural vision, many owners prefer to hire an architect first and choose a builder later. The design leads and the budget follows.
ADUs and additions are different. The design is shaped mostly by rules and by the lot: setbacks, size limits, utility routes, the condition of an existing garage, how a new room ties into the existing roof. Those are construction questions as much as design questions, and they are answered best when the builder is involved from the start. A lot review that compares the four ADU types, or weighs an addition against an attached ADU, is a planning job and a pricing job at once.
That is the reason Cedarline works as a design-build firm. From our base in Woodland Hills, we take ADUs, additions and new houses from the first look at the lot through drawings, permits and construction, so the plan you approve is one we have already priced. You can read more about our ADU construction, room additions and new construction services.