| Jeff R Sterling | Jeff R Sterling | — | (707) 599 9765 | GC, remodel, ADU | Redcrest · Humboldt County | — | — |
| Jeff Rau Floor Coverings | Jeff Rau Floor Coverings | — | (707) 599 8916 | Other | Eureka · Humboldt County | — | — |
| Jeff Tehan Plumbing | Jeff Tehan Plumbing | — | (707) 445 9193 | Other | Eureka · Humboldt County | — | — |
| Jeff Whitehead Construction | Jeffrey Allen Whitehead | — | (707) 267 1501 | GC, remodel, ADU | Fortuna · Humboldt County | — | — |
| Jenn Taylor Construction | Jennifer Danielle Taylor | — | (707) 601 8940 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Jeremy James | Jeremy James | — | (707) 362 9058 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Jes Karper Craftworks | Jes Karper Craftworks | — | (971) 517 8637 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Jesse Edge Construction | Jesse Wayne Edge | — | (707) 601 6658 | GC, remodel, ADU | Carlotta · Humboldt County | — | — |
| Jim Mc Laughlin | Jim Mc Laughlin | — | (707) 499 2504 | Windows, patio, painters | Mc Kinleyville · Humboldt County | — | — |
| Jlm Freedom Electric INC | Jason Lee Mayhorn | — | (707) 499 9771 | Electricians | Kneeland · Humboldt County | — | — |
| Jng Insulation Pros INC | Nathaniel Ryan Ludwig | jnginsulationpros@gmail.com | (707) 273 5018 | Other | Cutten · Humboldt County | — | — |
| Jnm Construction LLC | Jason Shawn Sefton | — | (707) 496 1380 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Jnm Construction LLC Design/build | Jnm Construction LLC Design/build | — | (707) 496-4380 | Other roofers | Eureka · Humboldt County | — | — |
| Joe Antrim Construction LLC | Joseph Scott Antrim | — | (707) 502 7857 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Joe Wilwerding Construction | Walter Joseph Wilwerding | — | (707) 445 5855 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Joe's Floor Covering | Joe's Floor Covering | — | (707) 407 5494 | Other | Eureka · Humboldt County | — | — |
| Joe's Landscape & Soil Service | Joseph Patrick Vassel | — | (707) 407 5515 | Windows, patio, painters | Fortuna · Humboldt County | — | — |
| Joey Berson Construction | Joseph Loren Berson | — | (707) 367 5257 | GC, remodel, ADU | Garberville · Humboldt County | — | — |
| Joey Latkiewicz Construction | Joseph Michael Latkiewicz | — | (503) 508 6920 | GC, remodel, ADU | Mc Kinleyville · Humboldt County | — | — |
| John H Kruger Plastering & Drywall | John Henry Jr Kruger | — | (707) 496 2722 | Other | Kneeland · Humboldt County | — | — |
| Johnny's Flooring And Window Coverings LLC | Brian Lloyd Mc Kenzie | — | (707) 726 7745 | Other | Fortuna · Humboldt County | — | — |
| Johns Group LLC | Nathan Lloyd Johns | — | (707) 725 3898 | Other | Hydesville · Humboldt County | — | — |
| Johnston Construction | Peter Riggs Johnston | — | (707) 499 8482 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Jonah Divine | Jonah Divine | — | (707) 442 1372 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Jones Woodworks | Jones Woodworks | — | (707) 498 8250 | Other | Mc Kinleyville · Humboldt County | — | — |
| Jordan Jackson Painting | Jordan Jackson Painting | — | (707) 499 9535 | Windows, patio, painters | Mc Kinleyville · Humboldt County | — | — |
| Josh Mitchell Construction | Joshua John Mitchell | — | (707) 845 5867 | GC, remodel, ADU | Arcata · Humboldt County | — | — |
| Josh Neff Construction | Joshua Forrest Neff | — | (707) 834 4315 | GC, remodel, ADU | Arcata · Humboldt County | — | — |
| Js Electric | James Charles Smith | — | (707) 223 1657 | Electricians | Garberville · Humboldt County | — | — |
| Jt Builds | Jt Builds | jaime@jtbuilds.com | (707) 683 9311 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Julien Construction | Lorne Matthew Julien | — | (707) 499 5455 | GC, remodel, ADU | Redcrest · Humboldt County | — | — |
| Junior Barns L L C | Russell David Friesen | — | (707) 725 2276 | GC, remodel, ADU | Fortuna · Humboldt County | — | — |
| Justin Adams Construction | Justin Layne Adams | — | (707) 496 4395 | GC, remodel, ADU | Kneeland · Humboldt County | — | — |
| Jz Contracting INC DBA Jz Contracting And Engineering | Jordan Mason Zizza | — | (707) 444 8007 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| K B Construction | Kent Michael Battle | — | (707) 498 1758 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| K C Construction | Keith Allen Combs | — | (707) 496 8081 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| K C Construction | Keith Edward Castonguay | — | (707) 496 4194 | GC, remodel, ADU | Mc Kinleyville · Humboldt County | — | — |
| K H Mc Kenny INC | Kevin Hugh Mc Kenny | — | (707) 444 9659 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| K Harrison Construction INC | Kyle Eugene Harrison | — | (707) 223 3554 | GC, remodel, ADU | Weott · Humboldt County | — | — |
| K J Construction | Keir Hanley Johnston | — | (530) 629 4445 | GC, remodel, ADU | Willow Creek · Humboldt County | — | — |