More room, without moving.
A single room or a full second story, designed and built to look like it was always part of the house, not added onto it.
What makes an addition look, and cost, like an afterthought.
- ×Plan check sending the drawings back twice, and nobody warning you that was normal.
- ×Plastic sheeting where your living room wall used to be, for a month longer than anyone said.
- ×A price that grows every time a wall opens up and something unexpected is behind it.
- ×A valley where the new roof ties into the old one, and a leak the first real winter.
All of it comes from the same root cause: design and structural review happening too late, instead of before anything gets drawn.
Structural review and design happen together, from the first sketch.
One team handles the design, the engineering questions, and the build, so a roofline or a foundation surprise doesn't derail the project halfway through. Licensed (CSLB #1071136), insured, and building in Orange County since 2018.
See how we work, start to finish →What additions typically cost in Orange County.
Additions price by the square foot more than most project types, and vary widely with foundation work. These are typical market ranges, not a KDB quote. We'll give you an honest number after we've actually seen your property.
| Addition Type | What It Is | Typical Range |
|---|---|---|
| Single-Story Room | Bedroom or den, no plumbing | $200 - $400 / sq ft |
| Bathroom or Kitchen Extension | Plumbing-heavy addition | $350 - $650+ / sq ft |
| Second-Story Addition | Structural reinforcement, stair integration | $350 - $650+ / sq ft |
Source: 2026 Southern California home addition cost surveys.
No surprises after the walls go up.
You see it before we start.
The same team that designs your addition builds it, so what you approve is what actually gets built.
We handle the structural review upfront.
Foundation and framing questions get answered before design commitments, not after the permit gets kicked back.
Open-book pricing throughout.
You see real costs as they happen, with a milestone schedule tied to real progress, not a lump estimate you have to take on faith.
A one-year workmanship warranty.
All labor is covered for a year after completion. If something isn't right, we make it right. No debate.
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