The Car Roof Box Guide

Whether you’re going away on a camping weekend, going on a cycling holiday, or have simply ran out of space in your car, a car roof box is the answer when you require extra space to transport your belongings. With the average cost of roof bars and a box coming in at around £200 - £400 ($300 - $600), it is a much cheaper solution than buying a bigger car – which is something that can cost thousands.

What is a car roof box?

A roof box is a plastic, waterproof container that sits on top of your vehicle. They are usually fixed to roof bars that you attach to the roof of your car, and they come in all shapes and sizes depending on your needs. There is a huge variety on the market, with the cheapest roof boxes coming in at just over £100 ($150), while the most expensive roof boxes can cost over £600 ($900).

The Mont Blanc Vista 320 is one of the cheapest roof boxes on the market

The Thule Motion 600 is in the high-end section of the roof box market

Choosing the right roof box

Choosing the correct roof box for your needs is crucial. There are many factors that come into play when deciding what roof box to purchase. Size, shape, length and width are all things you need to take into consideration when buying a roof box, along with the maximum load capacity of your car. The quality of the materials that make up the box and the safety features, such as the locking system, are also key areas in your decision making.

Maximum load capacity of your car

First things first, check your vehicle handbook to ensure you don’t exceed the car’s maximum load capacity. Remember to include the weight of the bars and the box when calculating the total weight on the roof.

Look at length and width – NOT litres!

When you look at the list of features for each roof box, you will see the length, width, height and capacity in litres. While the capacity can be a helpful guide as to the size of the box, it can also be slightly misleading. A couple of extra inches round the sides or on the top of the box will greatly increase the capacity of the box without actually adding any significant space to store your items. For this reason it is recommended that you use the length, width and height measurements when comparing roof boxes.

Read the Latest Roof Box Reviews

Think about the size and shape

The shape of the roof box will vary depending on what you need to transport. A typical family will require a medium width roof box, this will give adequate space for your belongings but will also allow you to carry other large items on the roof of your car, such as bikes or a kayak.

The biggest roof boxes, the ones that take up the full width and length of your roof space, are generally only a good idea if you are not planning to transport bikes or other large items on the roof. These boxes are very large, heavy and require two people to lift. As most people remove the roof box for everyday driving you will have to take into account the extra space that is required to store a large box. An alternative solution to buying a large box is to purchase two medium or small boxes and have them side by side. They will be easily managed by one person, and one box can be removed to make way for a bike or kayak.

Medium Sized Roof Box

Roof boxes come in all different shapes and sizes, choosing the correct one for your needs is important

Smaller Sized Roof Box

This is one of the smaller roof boxes, however it still has as much storage as a large boot

Make Safety A Priority

When you buy a roof box, you expect it to be an investment that will last for years. It therefore makes sense to purchase the very best one that you can afford, as the difference between a cheaper box and a top end box may only be a couple of hundred pounds. Paying that little bit extra could mean your box will last for several more years, and could mean it has extra features which makes it a little easier every time you use it.

The cheaper boxes tend to be made with thinner materials, and may not have the robust locking systems that are found on the mid to high range boxes. The thickness of the box can make a real difference when driving on the motorway. Thinner boxes tend to rattle more with every use, and eventually the fixings that hold the box together can become loose, which is a real danger if you are travelling at speed on a busy road. This isn’t an issue with the higher priced models, as they are made with better quality materials and thicker plastic.

Read the Latest Roof Box Reviews

Roof box locking systems

Another important area in the safety of a roof box lies in the locking system. Cheaper roof boxes tend to have one lock in the middle. This means it could be quite easy for thieves to prise open the ends of the box, where the lid meets the base, and take your belongings. Better quality boxes will have either locks on both ends (and possibly the middle too), or a central locking system where there is one key that locks several places around the box. If you are transporting bulky items in your roof box and you have to hold down each side to close it, it may be worth looking for a box that allows you to lock one side at a time.

Which side will your roof box open?

There are three options when it comes to choosing how your roof box opens – left side opening, right side opening, or dual side opening. If you have a full width roof box it makes sense to get one that opens from both sides, this makes it easier to load and unload the box from any side. If you have a narrow box, one that doesn’t take up the full width of the roof, then you will probably want to choose a box that opens on the same side as the side of the roof it will be situated on. This will prevent you having to stand on the sills of the car and reach over trying to put something in or get something out of your box. Another thing to consider is that if you park next to a wall or some other obstacle, it would be a good idea to get a box that opens on the opposite side from that obstacle.

Do I need roof bars to fit a roof box?

Roof bars are steel or aluminium bars that fix to your vehicles roof from side to side (door to door). Even if your car has factory fitted roof rails running across the long sides of the roof, you will still need to fit roof bars that run across the roof and fit to the rails.

You will still need to fit a set of roof bars even if your car has factory fitted roof rails

Roof bars will allow you to fit any size of roof box to your car

If you want to fit a roof box to your car, you will need to install roof bars first. A roof box must have something to attach to and cannot simply ‘sit’ on top of your roof. Roof bars are usually made specifically for each model of car, so be sure to double check that the roof bars you buy are suitable for your vehicle. The good news is that roof boxes are not specific to each model of car, therefore once you have installed your roof bars you are free to purchase any roof box you want.

Where to store your roof box

Roof boxes are great for extra space when you go on trips away from the house, but what about all those times where extra space is not needed? The majority of people remove their roof box when not in use, the increased fuel consumption and added height to the car being the main reasons. This means that you will need to think about where to store the roof box. If you are lucky enough to have a big garage, then this shouldn’t be a problem. There are solutions on the market that allow you to store the roof box above the car, such as a hoist that lifts the box up using a pulley mechanism to store it on the ceiling. You can also buy storage straps that work in the same way as a hoist, except there is no pulley mechanism to lift the box up. If your roof box is not too big, it can be stored in the shed, or perhaps even in the loft if you can manage to transport it up. If the worst comes to the worst, most roof boxes on the market today are very weather-proof, so it could be stored in the grounds around the house, maybe in the garden.

Check out my guide on the best Thule roof bike racks, see which one comes out on top!

See my guide on how to store a roof box to find the best place for yours

Best Sellers on Amazon

Mont Blanc Vista 320

Mont Blanc Vista 320 Roof Box
Capacity: 320 Litres
Length: 135cm
Width: 85cm
Height: 38cm
Weight: 11kg
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Green Valley Sherpack

Green Valley Sherpack Folding Roof Box
Capacity: 270 Litres
Length: 100cm
Width: 80cm
Height: 40cm
Weight: 3.8kg
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Mont Blanc Vista 450

Mont Blanc Vista 450 Roof Box
Capacity: 450 Litres
Length: 184cm
Width: 89cm
Height: 37cm
Weight: 20kg
Read the Latest Reviews