JB MECHANICAL INC DBA MAS SERVICE
California contractor license #498289 · Antioch, Contra Costa County
License
- License number
- 498289
- Status
- Clear
- Classifications
- C-20 Warm-Air Heating, Ventilating and Air-Conditioning Contractor
- C-38 Refrigeration Contractor
- Business type
- Corporation
- Issued
- Sep 15, 1986
- Expires
- Jun 30, 2028
- Workers' compensation
- Workers' Compensation Insurance — Insurance Company Of The West
- Contractor's bond
- $25,000 — Ohio Casualty Insurance Company (The)
- DIR public works registration
- Registered through Jun 30, 2027
From the California Contractors State License Board (CSLB) public license file, last updated Jun 8, 2026. Verify license #498289 on CSLB's License Check.
California public works
JB MECHANICAL INC DBA MAS SERVICE appears on 3 public works projects registered with the California Department of Industrial Relations, 3 of them as the prime contractor, for 1 awarding body between 2025 and 2026. Projects it led total $90,000 in reported contract value.
| Date | Project | Awarding body | Role | Contract amount |
|---|---|---|---|---|
| Jul 1, 2026 | HVACR/Kitchen Equipment Maint. & RepairsHVAC & mechanical | Alameda Unified School District | Prime | $30,000 |
| Jul 1, 2025 | Kitchen Equipment and HVACR ServicesHVAC & mechanical | Alameda Unified School District | Prime | $30,000 |
| — | Kitchen Equipment and HVACR ServicesHVAC & mechanical | Alameda Unified School District | Prime | $30,000 |
Most recent 3 of 3. Contract amounts are the whole project's, as the awarding body reported them to DIR (reported since July 2024); a role is "Prime" when the awarding body registered the contractor on the project.
Awarding bodies it works for most
- Alameda Unified School District · 3 projects
Is this your business?
Claim it on Atriam to add your work photos, service area and a booking link, and to run calls, leads, estimates and invoices in one place — free.
Claim this business