| Jack Canada Construction | John Milton Canada | — | (510) 719 4125 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Jack's Remodeling INC | Cindy Joanne Olmstead | — | (925) 676 2798 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Jackett Construction | Graham Lyle Jackett | — | (925) 825 4111 | GC, remodel, ADU | Clayton · Contra Costa County | — | — |
| Jackson And Son | Sammy Joe Jackson | — | (510) 799 9800 | GC, remodel, ADU | Hercules · Contra Costa County | — | — |
| Jacob Spilsbury | Jacob Spilsbury | — | (510) 798 7416 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Jacoby Painting & Sandblasting | Jacoby Painting & Sandblasting | — | (925) 998 7799 | Windows, patio, painters | Danville · Contra Costa County | — | — |
| Jacqueline M Seeno | Jacqueline M Seeno | — | (925) 671 7711 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Jacqueline M Seeno Construction Co INC | Jacqueline Michelle Seeno | — | (925) 671 7711 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Jager Flooring & Painting | Vitor Barbara Jager | — | (925) 766 6077 | Windows, patio, painters | Pleasant Hill · Contra Costa County | — | — |
| Jaggers Painting Company | Zachary Von Strehl Jaggers | — | (925) 584 6938 | Windows, patio, painters | Pittsburg · Contra Costa County | — | — |
| Jaime Anguiano | Jaime Anguiano | — | (510) 334 4933 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Jaime Canelo-hernandez | Jaime Canelo-hernandez | — | (510) 439 8662 | Windows, patio, painters | Richmond · Contra Costa County | — | — |
| Jake's Flooring INC | Brad Wade Jacobson | — | (925) 684 7098 | Other | Oakley · Contra Costa County | — | — |
| Jake's Paint & Paper | Jake's Paint & Paper | — | (510) 491 5914 | Windows, patio, painters | Discovery Bay · Contra Costa County | — | — |
| Jakes Electric | Stephen Charles Jayko | — | (925) 683 5559 | Electricians | Clayton · Contra Costa County | — | — |
| Jam3 Construction Innovation INC | Jesus Abner Martinez | — | (925) 544 6056 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| James A Bennett Landscape Design And Construction | James Allen Bennett | — | (925) 381 6266 | Windows, patio, painters | Moraga · Contra Costa County | — | — |
| James A Mayo Construction | James Anthony Mayo | — | (925) 798 1634 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| James Barry | James Barry | — | (415) 601 7663 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| James Benney Painting And Decorating | James Benney Painting And Decorating | — | (510) 421 0722 | Windows, patio, painters | Orinda · Contra Costa County | — | — |
| James D Rogers Builder | James D Rogers Builder | — | (510) 406 3217 | GC, remodel, ADU | Orinda · Contra Costa County | — | — |
| James Drysdale Granlund | James Drysdale Granlund | — | (925) 247 0128 | GC, remodel, ADU | Pacheco · Contra Costa County | — | — |
| James E Madison Concrete Repair | James E Madison Concrete Repair | — | (925) 872 3869 | Other | Concord · Contra Costa County | — | — |
| James E Roberts-obayashi Corporation | Larry Ralph Smith | — | (925) 820 0600 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| James F Boyle Construction | James Francis Boyle | — | (925) 683 5778 | GC, remodel, ADU | Crockett · Contra Costa County | — | — |
| James Frederick Senz DBA F G B Company | James Frederick Senz | — | (415) 317 3295 | GC, remodel, ADU | Orinda · Contra Costa County | — | — |
| James Frost Construction | James Ronald Frost | — | (925) 382 6851 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| James H Farr Construction Incorporated | James Howard Farr | — | (925) 228 9559 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| James Hewatt INC | James Paul Hewatt | — | (925) 240 6099 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| James M Campos | James M Campos | — | (925) 997 4529 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| James Minder Landscape Contractor | James Minder Landscape Contractor | — | (925) 262 3307 | Windows, patio, painters | Lafayette · Contra Costa County | — | — |
| James Ray Warford DBA Fixit Cricket | Fixit Cricket | — | (925) 337 1133 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| James Scott Busby | James Scott Busby | — | (925) 228 0522 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| James Thomas Construction | James Ogden Thomas | — | (925) 683 6432 | GC, remodel, ADU | Alamo · Contra Costa County | — | — |
| James Walker Co | James Robert Walker | — | (925) 575 1972 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| James Wimmer | James Wimmer | — | (925) 787 8489 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Jannisse & Sons Landscaping | Bryan Emil Jannisse | — | (925) 260 1521 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Janus Corporation | Michael Frederick Ely | — | (925) 969 9200 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Jaquith Construction | David Michael Jaquith | — | (925) 757 4453 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Jared Orozco General Contractor | Jared Orozco General Contractor | — | (925) 584 6869 | GC, remodel, ADU | Concord · Contra Costa County | — | — |