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FeaturedVerifiedRenovation Contractors in Petaluma, California

Underscore Design + Build

Featured in Petaluma Today 5.00 (10 reviews)(707) 785-6595

Underscore Design + Build is a general contractor based in Petaluma and focused on modernizing Sonoma County's vintage homes. Its project scope ranges from small repairs to full ADUs.

Business Highlights
  • Underscore is a family-oriented business.

Service Area

Sonoma County and Petaluma.

Featured on ProsGrade. Underscore Design + Build is one of 5 renovation contractors ProsGrade lists in Petaluma, California.

Listing details

6 services listed, including Kitchen and bath remodels and design, ADUs and Additions. Open weekdays, closed on weekends. Rated 5.0 from 10 reviews.

  • Verified listing details
  • Service information
  • Customer review signals
  • Photo gallery
  • Public contact information
  • Published local profile

How This Business Compares

How Underscore Design + Build compares with the other 4 renovation contractors on ProsGrade in Petaluma, using public Google ratings and review counts.

  • Ranks in the top half of the 5 Petaluma renovation contractors on ProsGrade by Google rating and review volume.
  • Rated 5.0 on Google, at or above the 4.8 average of other Petaluma renovation contractors on ProsGrade.
  • One of 5 Petaluma renovation contractors on ProsGrade rated 4.7 or higher from at least 10 reviews.

Services Covered

6 services
  • Kitchen and bath remodels and design
  • ADUs
  • Additions
  • New construction
  • Small repairs
  • Design/build auditsProject vision and budget alignment from the start

Reviews

What customers say

Customers praise Bill's communication and attention to detail. One customer credits his problem-solving and eye for quality with bringing a project in on budget.

Customer Reviews

michael albaum

Bill is hands down the BEST contractor I've ever worked with. Both in terms of craftmanship, but also in terms of his work ethic and professionalism. And finding a contractor who has both these days is tough to do. He shows up when he says he will and he charges what he says he will...no surprises. It's also amazing to see how creative Bill is when it comes to problem solving and determining the best solution for a project. His crews are incredibly efficient, professional and talented as well. I can't recommend Bill enough and he is my go-to when it comes to anything construction related! Thank you Bill!!!
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mathieu isaacs

What a great experience working with Bill and his team on a complete renovation of our studio building in Healdsburg. Bill is a problem solver and coupled with a great aesthetic and eye for quality, was able to bring our project in on budget. He was always available to answer questions and make recommendations to improve on our original plans. We are delighted with the project and highly recommend him.
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Stephanie Franco

Working with Bill was an absolute pleasure—truly a breath of fresh air. He was always available to discuss ideas, offer thoughtful input, and provide quick, accurate pricing for any project changes. His professionalism, communication, and attention to detail made the entire process smooth and stress-free. Bill’s commitment to both quality and aesthetics really stood out—he has a clear vision for the finished product and holds incredibly high standards to get there. Nothing was left unfinished or overlooked. We stayed in regular contact throughout the project, and he was always upfront and proactive about timelines and evolving needs. Pricing was fair, and Bill handled all the county permitting and payments, which made everything even easier on our end. He also spotted a water issue early on, addressed it quickly, and likely saved us from serious trouble down the line. On top of that, he created a custom enclosure for a water pump that doubled as extra storage—smart and functional. Highly recommend!
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Frequently Asked Questions

Does Underscore handle county permits?

On one customer's project, Bill handled the county permitting and payments.