Where to Store a Roof Box in the Off-Season
November 8, 2026 · 8 min read
The trip is over and the box is still on the roof, where it will stay until spring unless you find somewhere else for it. A 91-inch cargo box does not fit in a closet, hates damp concrete, and weighs enough that most people try the one-person lift once. This is roof box storage in an ordinary garage: where to put it and what each method needs.
Updated — first published
Quick answer
Store the box on edge against a garage wall on two padded brackets. That needs about 36 inches of floor depth and 8 feet of clear wall height, costs a pair of brackets and an afternoon, and keeps the lid seals off the damp concrete that ruins them.
The short answer
Put the box on the garage wall, on its long edge, on two padded brackets screwed into the studs. It is the cheapest way to get it off the ground and clear of the car, and the only method one person can set up in a morning. A hoist is tidier in a tall garage; the floor works if you can spare a bay.
This is for you if
- The box lives on the garage floor, in the way
- You take two or three trips a year and it rides up there in between
- Yours is a hard shell of 10 to 22 cubic feet, 35 to 60 pounds
Look elsewhere if
- You have a soft roof bag — fold it dry and shelve it
- You have a rooftop tent, whose fabric needs different care
How this guide was researched
Every figure here comes from a manufacturer manual or a federal data set, because Cedar Buy runs no tests.
Our selection method
- Thule roof box manuals and the Thule cargo box size guide, read in November 2026 for dimensions, weights and storage warnings.
- Space was weighted most heavily: garage room decides what you can use.
- Rented storage was excluded: buying space is a different question.
- Specifications come from manufacturer documentation. Cedar Buy does not physically test products — see our editorial policy.
Wall mount, ceiling hoist or floor
Choose by ceiling height first, then by how often the box comes off. Under 9 feet, the wall is your only real option. Above that, a hoist parks the box over the car and lowers it onto the roof.
Wall brackets, box on edge
Two brackets into studs, 24 to 32 inches apart, the box on its long edge. They must carry 35 to 60 pounds and be padded where they meet the shell.
Ceiling hoist
A pulley kit on the joists lifts the box flat above the car. The Thule MultiLift 2 is rated to 40 kg, or 88 pounds. Mounting it is a two-person job into real timber.
Flat on a shelf
The box lies on its base on a rack, sawhorses or plywood on blocks. Keep it 2 inches clear of the slab, so rising moisture cannot reach it.
The storage cover, which barely matters indoors
In a dry garage a fitted cover does little a cotton sheet would not. Buy one for a carport or a sunny window.
| Method | Space it needs | What setup costs | One-person job | Best for |
|---|---|---|---|---|
| Wall brackets, on edge | 36 in of depth, 8 ft of wall | Two brackets, eight lag screws | Yes, easier with a helper | A garage with one free wall |
| Ceiling hoist | 9 ft of ceiling, clear bay below | Hoist kit, plus hardware it omits | Lifting yes, mounting no | Tall garages, frequent trips |
| Flat on a shelf | 91 x 36 in, 2 in of clearance | Nothing, or plywood on blocks | Yes | A bay you can give up |
Space a box actually needs
Measure your box first, because the range is wide. A Thule Motion 3 M is 76.5 x 34.2 x 16.5 inches at 43.6 pounds; the Motion 3 XXL is 91.7 x 36.2 x 17.5 inches at 57.2 pounds. On the wall, length becomes height and width becomes how far it juts into the room.
So a large box on edge wants 8 feet of clear wall and 36 inches of depth, enough to block a car door. Mount it on the end wall ahead of the car and that depth costs nothing.
Protecting the seals and lid
Wash and dry the box before it goes away, then close the lid and lubricate the lock. Thule’s manuals say to clean a roof box with water and household washing liquid free of alcohol, bleach and ammonia, and to lubricate the locks with spray lubricant that never touches the plastic.
They are blunt about location: never store the box outside in rain or direct sun. Ultraviolet light embrittles the shell and hardens the gasket, and a hard gasket is the usual reason a quiet box starts whistling — see roof box noise: why it happens and how to stop it.
Road salt is the other killer. After a winter trip, rinse the mounting channel: salt left there corrodes next season’s clamps.
Leaving it on the car: the real cost
An empty box left up all winter costs fuel every mile. The US Department of Energy puts the penalty for a large, blunt rooftop cargo box at 2% to 8% in city driving, 6% to 17% on the highway and 10% to 25% at 65 to 75 mph. Thule’s manuals say to remove the box and bars when not in use.
A box on the roof also cannot go through an automatic car wash. For what the fuel side adds up to over a year, read how much does a roof box cost in fuel?
What the numbers do not show
Those percentages come from two test vehicles and one box shape. A tall SUV loses proportionally less than a low sedan, because the box sits in air the body already disturbed.
Getting it down alone
You can, and the trick is to slide rather than lift. Open the clamps, slide the box back until a third overhangs the roof, then rest that end on a sawhorse behind the car.
Then lift only the front end, half of 50 pounds, and walk it back onto the sawhorse. Never lift a full-length box straight off the bars alone: the span is 7 feet, and once it tips you cannot catch it.
Key terms, explained
Three words run through every storage instruction.
Plain-language definitions
- Gasket (also called the lid seal)
- The rubber strip around the rim that keeps water out when the lid shuts. It stays soft for years indoors, and hardens in a season of direct sun.
- Crossbar
- One of the two bars across the roof that the box clamps onto. Thule wants at least 700 mm, about 27.5 inches, between them.
- Hoist (sold as a multilift)
- A pulley kit bolted to garage joists that raises the box flat to the ceiling on straps. The Thule MultiLift 2 is rated to 88 pounds.
Mistakes that cost people money
The expensive one is stacking something on the lid: a deformed lid never seals again.
- Stacking anything on the lidUnclamped, a plastic lid carries no load. Snow tires on it for one winter leave a dip the gasket cannot bridge.
- Putting it away wet or saltyTrapped water grows mold and salt eats the clamps. Rinse, dry, then store.
- Screwing brackets into drywallA 57-pound box on drywall anchors comes off the wall, usually onto the car. Find the studs.
- Replacing a box that needs a gasketSeals and clamps are sold as spare parts. If you are weighing a secondhand replacement, buying a used cargo box: what to check lists the faults not worth fixing.
Frequently asked questions
Can you store a roof box standing on its end?
Store it on its long edge, not balanced on a short end. On edge, two brackets carry the load along the strongest part of the shell. Stood upright, a 7-foot box is top-heavy and all its weight presses on one corner.
Is it bad to leave a roof box on the car all year?
Yes, mainly because of fuel. The Department of Energy puts the penalty for a large rooftop box at 6% to 17% on the highway and up to 25% at interstate speeds, full or empty. You also cannot use an automatic car wash, and sun hardens the seal.
How much weight can a ceiling hoist hold?
The Thule MultiLift 2 is rated to 40 kg, or 88 pounds, which covers any hard plastic box. The real limit is the ceiling, not the hoist: it must bolt into joists or rafters, and the screws are often not supplied.
Can I store a roof box outside under a cover?
Indoors beats a cover every time. Manufacturers say not to store a roof box outside exposed to rain or direct sun, because ultraviolet light embrittles the shell and hardens the seal. A dry shed is fine; outdoors, use deep shade.
What to do this weekend
Measure the box, measure your wall, buy two brackets. One afternoon solves this for good.
With 8 feet of clear wall, the wall wins. With a ceiling over 9 feet and more than two trips a year, buy the hoist and have someone help you bolt it into the joists. Otherwise lay the box on plywood 2 inches off the slab, lid clear.
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