Bought a Plan Set? What Still Needs an Architect or Engineer
A ready-made plan set is the design layer of a project — the drawings that describe the building. It is a real head start, but it is not the whole project. Knowing what a stock plan usually leaves to a professional keeps your budget and your timeline honest.
The site-specific work a plan can't do for you
A stock plan is drawn to be broadly buildable, but it cannot know your particular lot. Several things almost always have to be prepared for your actual property:
- Foundation design — sized and detailed for your soil, slope, and conditions, which can require a soils report and structural engineering.
- Site and civil work — grading, drainage, and how the building sits on your lot.
- Utility connections — water, sewer or septic, power, and sometimes fire access, routed for your property.
- Code and energy details — current structural, energy, and accessibility requirements, which change over time and by jurisdiction.
Changes you request
The moment you alter a stock plan — move a wall, change the roof, adapt it to a tricky setback — you are back into design work, and that usually needs a professional. Small tweaks are minor; significant changes can approach a partial redesign. If you anticipate wanting a lot of changes, that is often a signal the project wants a custom design, as the stock vs custom comparison explains.
Who does what, and why licensing matters
Depending on the project and jurisdiction, the site-specific and code work may involve a structural engineer and, for many projects, a design professional to assemble and stamp the documents your city requires. The exact requirements for who must prepare and sign off on drawings are set by California and by your local agency, so confirm them for your project rather than assuming. The journal entry on who you actually need first sorts out the roles.
How this fits a design-build process
One advantage of handling the plan set, the site-specific work, and construction together is that the pieces are coordinated rather than handed between parties who have never spoken. Kevin Cohen Design can take a plan you have chosen and carry it through the site-specific layer, permitting, and build as part of our design-build services, so the gaps a plan set leaves are closed deliberately.
A plan set gets the building onto paper. Your lot, your code, and your changes still need a professional to finish the job.
Explore the ready-made plan sets in progress, or read about permits and plan-check if you already have a plan in hand.
General information only, not legal, engineering or code advice. Requirements for who must prepare and stamp drawings differ by jurisdiction and change over time; confirm the details for your property with your local building and planning departments and with qualified professionals.