California-licensed ADU specialist contractor based in Byron. CSLB #555444, class B. Identified in our directory because the business name explicitly contains an ADU keyword.
The data below is a snapshot of the CSLB Public Data Portal as of April 28, 2026. Status can change at any time (suspension, expiration, revocation, change in classifications, bond amount changes). Always click through to the CSLB Instant License Check above before signing any contract — that's the authoritative source, not us.
| License number | #555444 |
|---|---|
| Business name | Ray'S Mobile Modular Service |
| Primary status | CLEAR |
| Classification(s) | B |
| Business structure | Sole Owner |
| Issued | 1989-01-26 |
| Expires | 2028-01-31 |
| Mailing address | P O BOX 310, Byron 94514 |
| Phone | (510) 331 2952 |
| Contractor's bond | $25000 |
| Workers' comp coverage | Exempt |
Ray'S Mobile Modular Service has held a CSLB class-B (General Building) licence for 37 years (since 1989). Long-tenured contractor by California standards — most ADU specialist firms are post-2017 entrants drawn into the market by SB 1069 and AB 2299.
Business structure: Sole Owner. Sole-proprietor contractors carry personal liability for the work. Lien-recovery and CSLB-arbitration outcomes attach to the individual rather than a separate corporate entity.
Contractor's bond posted: $25,000 — the California statutory minimum for class-B contractors. Standard for the industry.
Workers' compensation coverage: Exempt. This typically means the firm has no W-2 employees and operates with the owner-operator alone (or with subcontractors who carry their own coverage). California requires W-2 employees to be covered. If this builder grows mid-project and hires staff, they must obtain coverage before those employees begin work.
A California class-B (General Building) contractor licence authorises the holder to take on building projects requiring at least two unrelated trades — framing + electrical, or concrete + plumbing + framing, etc. Almost all ADU work qualifies because an ADU is by definition a complete dwelling and requires multiple trades. A single-trade contractor (class C-10 electrical, C-36 plumbing, etc.) cannot prime an ADU project as general; they must subcontract under a B-licensed prime, or the homeowner must act as their own owner-builder.
This is a necessary condition, not a sufficient one. ADU construction has specific code requirements (Title 24 energy compliance, fire sprinklers in most jurisdictions, soils reports on sloped lots, accessibility provisions for JADUs) that not every B-licensed contractor has experience with. Ask for at least three completed ADU project references before committing.
Before signing a contract with Ray'S Mobile Modular Service or any builder, verify each of the following independently:
BackyardADU is an independent reference site. Ray'S Mobile Modular Service has not paid us to be listed. We do not endorse, rank, or vouch for the quality of any contractor's work. The profile above is derived from public CSLB Public Data Portal data (April 28, 2026 snapshot) and is provided as a starting point for your own diligence. The CSLB Instant License Check linked above is the authoritative source for current status.
If you're Ray'S Mobile Modular Service and want to update or remove this profile, contact hello@backyardadu.net. We respond to verifiable owner requests within 24 hours.