How to size a truck paint booth for your tallest unit

October 22, 2026 · Marathon Finishing Systems

To size a truck paint booth, measure the tallest, longest unit you will ever paint with everything bolted on it, then add work space around it. That one unit sets the door, the airflow choice, the lights and the layout. Most truck booths that come up short were sized to the average truck.

For the general method on any booth, start with our post on choosing the right spray booth size. This one is for trucks, buses, trailers and fleet equipment, and it comes from Marathon Finishing Systems, a spray booth manufacturer in Temecula, California.

What size paint booth do I need for a truck?

Size the booth to your tallest, longest, widest unit with the gear on it, plus work space on every side. Height is not the cab. It is the stacks, the roof air conditioner, the light bar, the ladder, the rack, the aerial. A 53' trailer typically stands around 13'6" tall, and a 40' transit bus runs around 10'6" to 11'6" with the roof air conditioner on it. Those are typical figures. Measure your own units, because the one with the odd roof gear sets the booth.

Length is the longest unit you will paint, bumper to hitch. Width is the widest point with mirrors out. Write all three down first.

Then add work space, because a booth sized to the part alone comes up short. Our rule of thumb is at least 3' on each side of the widest unit. If you run a personnel lift, plan on 4' to 5' from the side wall, since the basket sticks out, and about 6' above the top of the unit so the basket reaches the center of the roof. Leave extra at each end too, because the ends of a long unit are the darkest spots. Add it up and that is your working size. Our sales team will check it with you, so walk in with the numbers.

How big should the door be on a truck paint booth?

Size the door to the tallest unit with roof gear, not to the booth width. On our model tables the main door runs about 4'6" narrower than the booth width, so a 20' wide booth gets a door around 15'6" wide. Drafting confirms it for your booth. If your widest unit with mirrors needs more, tell us early so the header and door get drawn for it.

Door type is a floor space question. A barn door needs room to swing and park the leaf. Tri-fold and bi-fold doors fold back and take far less. A roll-up trades floor space for headroom.

Is a drive-through paint booth better than drive-in for trucks?

Drive-through is the layout we recommend for fleets. The unit enters one end, gets painted, and leaves the other. Nobody backs a 50' truck in with a spotter. The cost is space: you need clear room in front of both doors, so check the path outside the booth, not just the footprint inside. On our booths that is the Drive Through Upgrade, a second main door at the far end. Drive-in works when only one wall of the building is available. Plan the turning room, because every unit backs out the way it came in.

Which airflow is best for a truck or large equipment paint booth?

For a large vehicle, Side Down Draft and Reverse Flow are the two we reach for first. Reverse Flow brings filtered air in through the rear wall and out the front corners. It takes heat, suits sites where the doors stay open and the yard is dirty, and puts the heater and utilities at the back. It suits truck and equipment jobs where the exhaust has to leave from the front or the utilities sit behind the booth. Side Down Draft brings air down through the whole ceiling and out low plenums on both side walls, on a flat slab with no pit. It is the booth we lead with and our most widely specified pattern, and it holds up when two or three painters work a long unit at once. It costs 4' to 5' of extra outside width, so measure the building to the outside of the plenums.

Semi Downdraft (we call it Modified Down Draft) is not a true down draft. It is essentially a crossdraft with the intake in the ceiling. Air comes in through the front section of the ceiling and travels the length of the booth, so it earns its place on length in a bay that cannot give up width. Full Down Draft gives the best finish we build, but it needs a pit and the concrete work that comes with it.

Heat is available on Reverse Flow, Semi Downdraft, Side Down Draft and Full Down Draft. Heat is not available on Front Flow or Open Face. If you bake or force cure, that narrows the list before anything else does.

Lighting for tall sides

A ceiling full of fixtures lights the roof and leaves the sides and lower panels in shadow. On a tall unit that is most of the surface you are painting. Put fixtures in the side walls at more than one height, and add a low row for rockers, frame rails and fuel tanks. On tall booths, 2' fixtures along the lower wall are available as an option. The photo at the top shows it: fixtures in the ceiling corners and rows at two heights on each side wall.

What it looks like built: a heated Reverse Flow in Ohio

One of our Reverse Flow booths went to a specialty vehicle builder in Ohio. The working size is 20' W x 62'-7" D x 14' H. It carries (42) LED fixtures, (2) exhaust fans and an overhead mounted heater. A booth coat on the interior walls was added as an option, and a separate paint mixing room went in with it.

A 20' width leaves room on both sides of a wide unit for painters and a lift. A 14' height gives working height above a tall unit. And (42) fixtures in a booth that size means the light is on the walls, not just overhead.

We have built other truck and large equipment booths in Georgia, Texas and Tennessee. The Georgia booth is heated, 18' tall and 60' long. The Texas booth is a drive-through with a 62' working depth and (50) LED fixtures. The Tennessee booth is an outdoor heated drive-through, 50' long. Each was drawn around the units that go in it. You can see more on our truck and large equipment booths page.

Prep space

Prep throws more dust than paint and takes longer than the spray cycle. Every hour a truck spends sanding inside the booth is an hour the booth is not painting. If your volume justifies it, give prep its own bay with filtered air, sized for the same tallest unit. Parts and components can go to a PrepPro, which is portable. Settle prep before the booth is drawn.

The mixing room

If you mix your own paint, plan the room now. A separate paint mixing room keeps cans, the mixing bench and supplies out of the spray area. We build paint mixing rooms in standard sizes and can join one to a booth with a vestibule when the layout allows. How much paint you can store in it follows your local fire code, so check with your fire official before picking a size.

When the building is full: an outdoor booth

If there is no bay to give up, there may be a yard. Outdoor rated booths come in Reverse Flow, Side Down Draft and Full Down Draft, with a shell built for the weather and heat for cold climates. Wind and snow loads get drawn in for your site. The owner handles the slab, permits, power and gas, and fire suppression comes from your own fire suppression company, who will want the booth height early. We do not do permitting or suppression. Engineering documentation is available upon request.

Bring us the tallest unit with roof gear, the longest unit, the widest point with mirrors, and what the building or yard allows. Do you need it drive-through? Send us those numbers or hop on a call, and we will tell you what fits.