A stock mobile office trailer is a single-wide unit that is already built, already carries its California HCD insignia, and is parked in inventory waiting for a buyer. Because there is no factory build and no new plan check, a stock office trailer is usually the fastest way to get a working office on a California job site, sales lot or yard.
What counts as a stock mobile office trailer
Mobile office trailers are single-wide commercial coaches: one module, built on its own steel chassis with axles and a towing hitch. In California they are approved by HCD and carry the state insignia. A “stock” trailer is one that is finished and sitting in a dealer or owner yard right now — not on order, not waiting on approval. Buy it, and the main work left is transport, setup and hookups.
Stock trailers stay on their running gear in storage. That is why the units in the image at the top of this page are shown on their chassis with hitches, tandem axles and jack stands — that is what a ready-to-move office trailer looks like before delivery.
Common stock office trailer sizes
Office trailers come in a range of single-wide sizes. These four cover most of what buyers ask us for:
| Size | Square feet | Typical use | California transport |
|---|---|---|---|
| 8′ x 32′ | 256 SF | One-person site office, guard or ticket office, plan room | Legal width (8’6″ or less) — no oversize permit |
| 10′ x 44′ | 440 SF | Superintendent office with a second private office, small sales office | Oversize permit, no escort |
| 10′ x 50′ | 500 SF | Conference room, open office and private office | Oversize permit, no escort |
| 12′ x 60′ | 720 SF | Full field office with two private offices, open area and restroom | Oversize permit, no escort |
Width matters more than length for delivery cost. An 8′-wide unit moves at legal width with no oversize permit. 10′ and 12′ wide units need a single-trip oversize permit in California but no escort car. Anything wider than 12′ pulls in escort cars and a midday no-travel window, which is why office trailers top out at 12′ wide.
Typical office trailer floor plans
These four layouts are the standard single-wide office trailer sizes you will see across rental and resale fleets. Click any plan to enlarge it, or print it to sketch on.
8′ x 32′ — private office and open work area
A compact dry unit: one private office plus an open area for two desks and a plan table, with a door at each end of the work area.
View full size | Print floor plan
10′ x 44′ — two private offices and open office
Two private offices at the ends, an open office in the middle and a small restroom tucked into the back corner.
View full size | Print floor plan
10′ x 50′ — conference room, open office and private office
Adds a conference room, a kitchenette counter and a restroom, with a private office at the far end.
View full size | Print floor plan
12′ x 60′ — conference room, open office and manager office
The full-size field office: conference room, four workstations, kitchenette, restroom and a large manager office, with two entry doors.
View full size | Print floor plan
Wet vs. dry trailers
- Wet — includes a restroom (toilet and sink). Needs water and sewer connections on site, but it is self-contained.
- Dry — no plumbing. Simpler, cheaper and faster to set up. Common on short-term construction jobs where the site already has restrooms or portable toilets.
Every stock trailer has its HVAC built in: a wall-mount packaged unit on one end wall, so there is no separate condenser to set on the ground.
When a stock office trailer is the right call
- You need an office on site in weeks, not months.
- A standard layout — private offices, an open work area, maybe a restroom — fits how you will use it.
- The building may move again: a trailer on its own chassis relocates far more easily than a set-down modular building.
- You want to own the unit instead of paying rent month after month.
If you need more than about 720 SF, a layout built around your program, or classroom use, look at multi-section units instead — see stock modular buildings in California.
What happens after you buy
Delivery, setup and hookups are planned around your site. The trailer is towed in on its own running gear, leveled and set on supports, and steps or a ramp are added at the doors. Electrical, and water and sewer for a wet unit, are connected by licensed trades. Site work and local permits are the buyer’s responsibility — we will tell you what to expect up front so nothing surprises you.
Ready to look at what is in stock? Call (800) 806-7485 or request a quote, and tell us the size, how you will use it, and where it is going.
Frequently asked questions
How fast can a stock office trailer be delivered?
Most stock office trailers can be delivered within a few weeks of purchase, because the unit is already built and already carries its California insignia. Actual timing depends on what is in inventory, transport permits for 10′ and 12′ wide units, and how ready your site is.
Do stock office trailers come with a restroom?
Some do. A “wet” trailer has a toilet and sink and needs water and sewer hookups on site. A “dry” trailer has no plumbing and is usually paired with site restrooms or portable toilets. A 12′ x 60′ has room for a restroom with about 660 SF left over; on an 8′ x 32′ a restroom takes a large share of the floor.
Why do stored office trailers still have wheels and a hitch?
A single-wide office trailer is built on its own steel chassis with axles and a towing hitch. Stock units are stored that way so they can be moved and delivered quickly. On site, the unit is leveled and set on supports, and the running gear can stay with the unit for the next move.
Can I add a ramp to a stock office trailer?
Yes. Ramps and steps are added on site to fit the building’s use. If the public will visit the trailer, plan for an accessible ramp and landing. See our ADA ramp guide for what that involves.
Does iModular.com sell stock office trailers outside California?
Yes. iModular.com brokers modular buildings nationwide. The California details on this page — HCD insignia, permits, transport — are specific to California; call (800) 806-7485 to talk through a project in any state.
Related California resources
- Stock modular buildings in California
- Construction site office trailers in California
- Real estate, auto dealer and sales office trailers in California
- Transportation and logistics dispatch offices and guard shacks in California
- ADA ramp requirements for California modular buildings
- Modular building foundation systems in California
iModular.com — California modular building specialists since 1998. Last updated October 2026.
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