Why are prefab, modular homes, and park models so narrow?

Why are prefab, modular homes, and park models so narrow?

Why are prefab, modular homes, and park models the size they are?

One factor in the size of sheds, prefab cabins, park model homes and the parts of modular homes is the size that can be transported and delivered to you.

Photo by Eric Jones

12-feet wide

Have you noticed that the price jumps to buy anything more than 12-feet wide?

If something is only 12-feet wide and 8.5-feet high or less, it can be moved much more easily and inexpensively. If it is any bigger, it costs more to deliver. They have to have a car leading the truck transporting the cabin, shed or home module.

Photo by John Dickenson

14-feet wide

It is even more expensive to deliver a cabin or part of a modular home that is over 14-feet wide. Depending on where you are, a wider load may need an additional travel escort. One leading and another one following the wide load.

16-feet wide

In North Carolina, something 16-feet wide can be moved only from 9:00 am to 2:30 pm Monday through Saturday. The rules specify other areas and times that are not allowed. The trucking company has to get a permit to transport the size and stick to specified routes. They complete an application for the specific route that defines the transporter and the certified escort driver.

The transport vehicle has to be rated (GVWR) no less than 2 tons and minimum requirement of 4-speed transmission with two braking axles, tail and turn signals on the rear of the mobile/modular unit and 7 x 14.5 or larger, 8 ply, 10 ply or 12 ply rated tires with tread depth not less than 2/32 inch.

They have to display:

  • A 7’ long, 18” high yellow banner on the transport vehicle saying the WIDE __ FT LOAD or OVERSIZE __ FT LOAD with the accurate width.
  • Red or orange 18” square flags on all four corners of the mobile/modular unit 50” from the road surface.
  • Flashing amber lights visible for 500’ feet and 360 degrees are required to be displayed 72” from the road surface on all 4 corners of the mobile/modular home. Or they can mount the front lights on the mirror bar “no less than the extreme width of the power unit.”

They have to have two way radio contact with the escort vehicles.

So, that is at least three vehicles and four people involved. No wonder they charge so much!

Photo by Jaggery


The height matters, too. Often it doesn’t cost a lot more to buy a taller building, but the cost of transportation can go up. Sometimes way up.

It’s not just the height of the building or whatever. It is the height of the building plus the truck it is on.

Rattler High Pole Package for Oversize Load Truck Pilot Car
Ebay Rattler High Pole Package – Oversize Load Truck Pilot Car >

Pole indicator required for front escort vehicle for over height units in excess of 14’ 5”.

The pole on the pilot car is the height of the load. If it can pass, the house or whatever is on the truck can.

If it is too high, it can’t fit under power-lines or trees or tunnels… as easily or at all. They will have to alter the delivery route or take the building off the truck and transport it the rest of the way using just wheels and what they call a mule, “an ingenious and highly maneuverable forklift-type device.*

Pilot car escort with safety equipment
Photo by Patrick Cartwright Jr

Oversized Loads

In general, the maximum legal load width is 8.5 feet (102 inches), and the maximum height limit is also 102 inches. Legal length is typically 48 to 53 feet, and the maximum weight is about 46,000 pounds.

In many states, shipments over 12 feet wide require travel escorts (or “pilot vehicles”). In addition to variable per-mile rates, shippers typically pay for hotels and other incidentals, known as accessorials, and would be included as part of the overall freight costs.

The role of travel escorts is to forewarn flatbed drivers of special circumstances, like accidents, construction zones, bridges, low wires, traffic jams, and other hazards that require careful driving. They also serve in alerting the public of the presence of an oversized vehicle.

CH Robinson (a trucking company)

Oversized Load, Jackson, Wyoming
Photo by Dietmar Rabich

What size is an Oversized Load?

These are the rules where we live, in North Carolina.

Dimensions Width: 8’6″ (8′ other roads) Height: 13’6″Semi Trailer Length: 53′ (non-designated Hwys: 48′) Maximum Length: 110′ (non-designated Hwys: 60′) Legal Overhang: Front/Rear: 10′

North Carolina Pilot Cars / Escorts

For permitted loads more than 12 feet wide on:

  • Two-lane/two-way traffic highways: One front escort required
  • Multi-lane highways: Rear escort is required or as determined and stated on the permit document by issuing agent.

Permitted loads exceeding 14 feet in width on:

  • Two-lane/ two-way roads: Front and rear escort required

Additional escorts may be required for any vehicle or vehicle combination with individual consideration of weight, width, length, height, weather, geographical location or route of travel as determined by issuing agent.

Note: Escort vehicle requirements for 16-foot-wide mobile/modular homes are different from those for other escort vehicles.

Pilot cars (escort vehicles) may be:

  • A truck of not less than a one-quarter-ton rated load capacity but not more than 17,000 pounds GVWR
  • A passenger vehicle of not less than 2,000 pounds gross weight.

Escort Operators

All escort vehicle operators are required to obtain an approved escort certification prior to performing the duties of an oversize/overweight load escort vehicle operator in North Carolina.