| Flatiron/kiewit A Joint Venture | Infrastructure West Co Kiewit | — | (707) 742 6000 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Flatirondragados Aecon A Sites Joint Venture | Pacific Northwest INC Aecon | — | (707) 742 6000 | Other | Concord · Contra Costa County | — | — |
| Flatirondragados Sukut Adsrp Joint Venture | Construction LLC Sukut | — | (707) 742 6000 | Other | Concord · Contra Costa County | — | — |
| Flatirondragados-bessac Vista Grande Jv | Dragados West LLC Flatiron | — | (707) 742 6000 | Other | Concord · Contra Costa County | — | — |
| Flatirondragados-gsb I St Bridge Jv | State Bridge INC Golden | — | (707) 742 6000 | Other | Concord · Contra Costa County | — | — |
| Fleece Corp | Edward Leon Flies | interested@domainmarket.com | (925) 303 0302 | Other | Concord · Contra Costa County | — | — |
| Fleury's Floor Covering INC | Kimberlee B Fleury | — | (925) 676 1010 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Flex Paintings | Flex Paintings | flexpaintingsinc@gmail.com | (925) 497 2645 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Flipper Roofing And Construction INC | Jerry Russell Kanawyer | — | (925) 634 7047 | Other roofers | Byron · Contra Costa County | — | — |
| Floor Changers | Floor Changers | customerservice@floorchangers.com | (510) 799 9689 | Other | Hercules · Contra Costa County | — | — |
| Floor Design By R J S | Robert John Stuscavage | — | (925) 250 4789 | Other | Martinez · Contra Costa County | — | — |
| Floor Man INC | Timothy Keith Vieira | — | (925) 778 3454 | Other | Antioch · Contra Costa County | — | — |
| Floor Tech's | Floor Tech's | — | (408) 410 0125 | Other | Discovery Bay · Contra Costa County | — | — |
| Floor To Ceilings | Floor To Ceilings | — | (925) 246 9363 | Other | Concord · Contra Costa County | — | — |
| Floor's By Contract INC | Jorge Saul Calles | — | (925) 334 2410 | Other | Pittsburg · Contra Costa County | — | — |
| Floors By Darryl | Floors By Darryl | — | (925) 200 5007 | Other | Concord · Contra Costa County | — | — |
| Floors By Leo | Floors By Leo | leo@floorsbyleo.com | (925) 595 0777 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Floors4u INC | Alexander Michael Cooper | — | (925) 457 8474 | Other | Walnut Creek · Contra Costa County | — | — |
| Floorscapes | Jeffrey Stephen Burlison | — | (925) 212 8666 | Other | Walnut Creek · Contra Costa County | — | — |
| Flores Carpentry | Flores Carpentry | — | (925) 864 8175 | Other | Concord · Contra Costa County | — | — |
| Flores Carpentry INC | Heber Noe Flores Ortega | — | (925) 864 8175 | Other | Concord · Contra Costa County | — | — |
| Flores Landscape And Gardening | Flores Landscape And Gardening | — | (925) 642 9540 | Windows, patio, painters | Antioch · Contra Costa County | — | — |
| Flores Tree & Landscape | Flores Tree & Landscape | — | (925) 727 5496 | Windows, patio, painters | Antioch · Contra Costa County | — | — |
| Flow Pro Plumbing | Jesse Lee Delgado | — | (925) 329 0050 | Other | Brentwood · Contra Costa County | — | — |
| Flowing Water | Brian Joe Bristol | firerockcareers@nnge.org | (925) 270 3195 | Other | Pacheco · Contra Costa County | — | — |
| Flowmotion Plumbing | Flowmotion Plumbing | ryan_frantz@flowmotionplumbing.com | (925) 219 7966 | Other | San Ramon · Contra Costa County | — | — |
| Fluid Dynamics | Fluid Dynamics | — | (510) 313 8240 | Other | Pinole · Contra Costa County | — | — |
| Flushitdown LLC | Travis Dale Ballard | — | (510) 830 9474 | Other | Martinez · Contra Costa County | — | — |
| Flynn Electric | Dion Dannial Flynn | — | (925) 899 6182 | Electricians | Clayton · Contra Costa County | — | — |
| Flynn Plumbing | Jeramy Len Sossaman | info@flynnplumbing.com | (925) 687 9701 | Other | Concord · Contra Costa County | — | — |
| Focus Realty Services INC | Daniel Joseph Freeman | interested@domainmarket.com | (925) 283 8470 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| Fog Bank Construction | Steven Edgar Hays | — | (925) 383 3790 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Fong's Construction | Fong Lawrence | — | (415) 828 9169 | GC, remodel, ADU | Hercules · Contra Costa County | — | — |
| Fonseca Electric | Juan Saul Fonseca Torres | — | (415) 240 2374 | Electricians | Richmond · Contra Costa County | — | — |
| Fonseca Roofing INC | Fonseca Martin | — | (925) 550 4491 | Other roofers | Oakley · Contra Costa County | — | — |
| Fonseca's Drywall | Fonseca's Drywall | — | (415) 828 5693 | Other | Richmond · Contra Costa County | — | — |
| Food Service Equipment Installation | Thomas Andrew Banis | — | (925) 934 1212 | Other | Walnut Creek · Contra Costa County | — | — |
| Ford Electric | Benjamin Lowell Ford | — | (925) 437 2365 | Electricians | Antioch · Contra Costa County | — | — |
| Forge Construction Services INC | Danylo Zakusilov | — | (925) 489 9719 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Form+function Builders | Form+function Builders | info@formfunctionbuilders.com | (415) 260 3742 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |