Home Additions

Design-build home additions in the Bay Area — one team from first sketch to final walkthrough.

Licensed · CSLB #1057737 · Design-Build Since 2019 · 5.0 Stars on Google · Alameda Showroom · 1-Year Warranty · Financing Available
Front view of a second-story addition in Redwood City by New Bay Builders

More space, designed to blend with your home

New Bay Builders is a design-build remodeling firm (CSLB #1057737) serving Contra Costa, Alameda, and Marin counties since 2019. From room additions to second stories, our in-house team designs and builds new space that looks like it was always part of your home.

Every project starts with a free consultation and is documented in a detailed written scope — so you know exactly what’s included before we begin. And every addition we build is backed by our 1-Year Warranty.

What’s included

Every addition is different. A typical scope with New Bay Builders may include:

  • Design & planning — new space planned to blend with your existing home
  • Foundations & framing — structural work for your addition
  • Roofing tie-in — new roof integrated with your existing roofline
  • Structural engineering coordination — beams, footings, and load paths planned with engineers
  • Electrical, plumbing & HVAC — systems extended into the new space
  • Exterior finishes — siding, windows, and doors matched to your home
  • Interior finishes — flooring, paint, and trim consistent with your home
  • Permits handling — we prepare and manage the permit process for your project

Your exact scope is documented in a detailed written proposal before work begins — no surprises.

Our process

A clear path from first conversation to final walkthrough.

1

Consultation

Tell us about the space you need in a free consultation.

2

Design

We design the addition to match your home’s style.

3

Detailed Scope

You receive a detailed written scope and quote.

4

Build

Our team builds your addition with permits handled.

5

Final Walkthrough

We walk through every detail together before sign-off.

Recent addition work

Addition projects across the Bay Area — including this second-story addition in Redwood City.

Aerial rear view of second-story addition, Redwood CityBackyard view of second-story addition, Redwood CityFront of home addition project, Jefferson Ave Redwood CityGarage addition, Jefferson Ave Redwood City

Home addition FAQs

Do you offer free consultations?

Yes. Every project starts with a free consultation — at your home or in our Alameda showroom at 2515 Santa Clara Ave, Suite 207 (by appointment).

Will I receive a written scope before work begins?

Yes. You’ll receive a detailed written scope and quote so you know exactly what’s included before construction starts.

Is your work covered by a warranty?

Yes. Every project is backed by our 1-Year Warranty.

Do you offer financing?

Yes — financing is available. Ask us about options during your free consultation.

Ready to Start?

Schedule your free consultation today.

Call (510) 295-3205Free Consultation

Proudly serving 44 cities across Contra Costa, Alameda & Marin counties — see our Areas We Serve.