| Roger's Design | Roger's Design | — | (561) 799-2545 | Windows, patio, painters | Rio Dell · Humboldt County | — | — |
| Rogers Machinery Company INC | Austin Alan Chilcott | — | (408) 816 8321 | Other | Eureka · Humboldt County | — | — |
| Ron Lundblade Construction | Ronald Bryon Lundblade | — | (707) 499 4961 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Ronald Beauchamp | Ronald Beauchamp | — | (707) 599 7121 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Ronald C Buschkamp | Ronald C Buschkamp | — | (707) 499 9687 | GC, remodel, ADU | Mc Kinleyville · Humboldt County | — | — |
| Roof Restoration And Exteriors | Carlos Omar Corradini | — | (707) 497 8879 | Other roofers | Mc Kinleyville · Humboldt County | — | — |
| Roots Power | Robert John Satava | — | (707) 441 9436 | Electricians | Eureka · Humboldt County | — | — |
| Rory Stevens Construction | Stevens Rory | — | (707) 223 0522 | GC, remodel, ADU | Fortuna · Humboldt County | — | — |
| Roslosnik Repair & Construction | Brett Alan Roslosnik | — | (707) 496 0568 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Ross Carey | Ross Carey | — | (818) 961 5174 | Electricians | Eureka · Humboldt County | — | — |
| Royse Restoration | Royse Restoration | — | (707) 498 1931 | GC, remodel, ADU | Fortuna · Humboldt County | — | — |
| Rp Humboldt INC DBA Renaissance Painting | Seth Alan Newkirk | — | (707) 443 8936 | Windows, patio, painters | Eureka · Humboldt County | — | — |
| Rp Rice Construction INC | Ryan Patrick Rice | — | (707) 845 7423 | Other | Hydesville · Humboldt County | — | — |
| Rs Metalworks | Rs Metalworks | — | (707) 328 8826 | Other | Eureka · Humboldt County | — | — |
| Russell Skipper DBA Troy Skipper Construction Co | Russell David Skipper | — | (707) 443 3710 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Ryan Construction | Bruce Leland Ryan | — | (707) 822 6102 | GC, remodel, ADU | Arcata · Humboldt County | — | — |
| Ryan Harvey Construction | Ryan Lytle Harvey | — | (707) 599 2300 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Ryan Henry Construction | Ryan Carl Henry | — | (707) 496 3218 | GC, remodel, ADU | Fortuna · Humboldt County | — | — |
| Ryan Miller | Ryan Miller | — | (707) 496 0271 | GC, remodel, ADU | Ferndale · Humboldt County | — | — |
| Ryan Sullivan | Ryan Sullivan | — | (707) 845 1253 | GC, remodel, ADU | Bayside · Humboldt County | — | — |
| S & S Phelps INC | William Kevin Scott Ii Phelps | — | (707) 845 8083 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| S T S Construction | Shane Todd Streeter | — | (707) 845 3345 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Safier Construction Company | Roger Kenneth Safier | — | (707) 499 1384 | GC, remodel, ADU | Petrolia · Humboldt County | — | — |
| Sager Construction | George Alvin Iii Sager | — | (707) 548 2572 | GC, remodel, ADU | Mc Kinleyville · Humboldt County | — | — |
| Salt & Spray Construction | Alexandr Cipactli Smeloff | — | (707) 497 4308 | GC, remodel, ADU | Mc Kinleyville · Humboldt County | — | — |
| Samara Landscaping | Eric Jacob Johnson | estimates@samaralandscaping.com | (707) 601 3478 | Windows, patio, painters | Arcata · Humboldt County | — | — |
| Sample Construction | Kyle Wayne Sample | — | (707) 499 3073 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Samson Construction Services | Allen Neal Samson | — | (707) 499 5073 | GC, remodel, ADU | Arcata · Humboldt County | — | — |
| Sanborn Design Build | James Wessling Sanborn | — | (707) 953 9567 | GC, remodel, ADU | Ferndale · Humboldt County | — | — |
| Sandberg Construction | Joshua Timothy Sandberg | — | (707) 599 5792 | GC, remodel, ADU | Fortuna · Humboldt County | — | — |
| Sanders Roofing INC | Robert Allen Sanders | office@bsandersroofing.com | (707) 443 0503 | Other roofers | Fields Landing · Humboldt County | — | — |
| Sanderson Remodeling | Sanderson Remodeling | — | (707) 599 3614 | GC, remodel, ADU | Carlotta · Humboldt County | — | — |
| Sargent Excavation | Jeremy Michael Sargent | — | (707) 407 5137 | Other | Mc Kinleyville · Humboldt County | — | — |
| Savercool Construction | Jeffrey Scott Savercool | — | (707) 443 8619 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Scharnberg Construction | Tate Nathan Scharnberg | — | (707) 497 8325 | GC, remodel, ADU | Arcata · Humboldt County | — | — |
| Schuler Construction | Tony Alan Schuler | — | (707) 498 7266 | GC, remodel, ADU | Kneeland · Humboldt County | — | — |
| Schweigert Electric | Stan C Schweigert | — | (707) 601 1521 | Electricians | Blue Lake · Humboldt County | — | — |
| Scott Construction | Scott Allen Reinsmith | general@scott-construction.com | (707) 498 1895 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Scott Emmons Drywall | Scott Emmons Drywall | — | (707) 839 1065 | Other | Mc Kinleyville · Humboldt County | — | — |
| Scurfield Electric Heating & Solar | Benjamin Garland Scurfield | — | (707) 825 0759 | HVAC | Arcata · Humboldt County | — | — |