Roof Box Insurance Guide: What You Need to Know

Installing a roof box on your vehicle is considered a modification by UK insurers, and failing to notify your insurance company could invalidate your entire policy. This guide explains everything you need to know about roof boxes and car insurance to ensure you're properly covered.

Rich posted 4 weeks ago •
6 min read
Last updated: November 24th, 2025

Quick Summary

Legal Requirement

UK insurers classify roof boxes as vehicle modifications requiring immediate notification before fitting.

Policy Invalidation Risk

Failing to notify your insurer can void your entire policy and result in rejected claims.

Minimal Cost Impact

Most insurers charge u00a310-50 annually, with many offering free temporary use notification.

Comprehensive Coverage

Car insurance covers the roof box itself, but separate coverage needed for contents inside.

Why You Must Notify Your Insurer About a Roof Box

UK insurance companies classify roof boxes as vehicle modifications, even if they’re only temporarily fitted. This means you have a legal obligation to inform your insurer when you install one, whether it’s a permanent fixture or just for a weekend trip.

  • Any modification to your vehicle must be disclosed to your insurer
  • Roof boxes are considered modifications even when temporarily fitted
  • Rental roof boxes also require notification
  • Failure to notify can void your entire insurance policy

Consequences of Not Notifying Your Insurer

  • Policy invalidation: Your entire insurance policy could be void, not just for roof box-related claims
  • Rejected claims: Any claim could be refused, even if completely unrelated to the roof box
  • Legal issues: Driving without valid insurance is illegal and carries serious penalties including fines up to £300 and 6-8 penalty points
  • Financial liability: You’d be personally liable for any damage or injury caused in an accident
  • Future insurance problems: Having had insurance invalidated makes it difficult and expensive to get coverage in future

How to Notify Your Insurance Company

Contact your insurer before you first fit the roof box. Most insurers offer several notification methods:

  • Online account: Many insurers have online modification notification systems
  • Phone: Call your insurer’s customer service line (quickest method)
  • Mobile app: Some insurers allow modification notifications via their app
  • Email: Written confirmation provides a paper trail for your records

Information You’ll Need to Provide

  • Roof box make and model (e.g., Thule Motion XT, Halfords 420L)
  • Capacity/size in litres
  • Approximate value of the roof box
  • Whether it’s permanent or temporary installation
  • Installation date
  • Whether you own or rent the roof box

Cost Implications and Premium Changes

The good news is that roof boxes typically have minimal impact on insurance premiums:

Typical Premium Changes

  • Average increase: £10-50 per year for permanent installation
  • No increase: Many insurers don’t charge extra for seasonal/temporary use
  • Mid-term notification: Usually free to add to existing policy
  • Renewal impact: May be factored into next year’s premium calculation

Roof Box-Friendly Insurers

Some UK insurers are particularly understanding about roof boxes:

  • Adrian Flux: Specialist in modified vehicles, often no premium increase
  • LV=: Generally accepts roof boxes as standard equipment
  • NFU Mutual: Rural insurer familiar with roof box use
  • Direct Line: Often includes roof boxes without additional charge
  • Saga: Good for over-50s, usually no extra cost

What’s Covered and What’s Not

Roof Box Coverage

  • Comprehensive insurance: Usually covers the roof box itself against theft and damage
  • Third party, fire and theft: May cover theft but not accidental damage to the box
  • Third party only: Typically doesn’t cover the roof box at all

Contents Insurance

Your car insurance doesn’t automatically cover items stored in your roof box:

  • Home contents insurance: May extend to items in roof box, but check policy limits and excess
  • Travel insurance: Often covers luggage in roof boxes during trips abroad
  • Specialist policies: Consider additional coverage for expensive equipment like ski gear or bikes
  • Typical exclusions: Items left in roof box overnight in public areas often not covered

Common Policy Exclusions

  • Damage from improper installation
  • Damage from overloading beyond weight limits
  • Wear and tear
  • Damage from automated car washes (some policies)
  • Items left unattended in public car parks overnight

Special Considerations for Rental Roof Boxes

If you’re renting a roof box rather than purchasing one, you still need to notify your insurer:

  • Temporary modification: Treat it as a temporary modification during the rental period
  • Rental company insurance: The rental company’s insurance covers their equipment, but not your car or contents
  • Damage liability: You’re usually liable for damage to the rental roof box – check your policy covers this
  • Short-term notification: Some insurers allow notification via phone for weekend rentals
  • Fitting damage: Ensure your policy covers damage to your vehicle caused during installation

Making a Claim Involving Your Roof Box

Theft of Roof Box or Contents

  1. Report to police immediately and obtain crime reference number
  2. Contact your insurer within 24 hours
  3. Provide proof of purchase or rental agreement
  4. Submit photos of the roof box and installation (take these when first fitted)
  5. Show evidence of locking mechanisms used
  6. List contents that were stolen with values

Damage Claims

  1. Document damage with photos from multiple angles
  2. Don’t remove the roof box until insurer advises
  3. Get repair quotes from approved repairers if possible
  4. Keep all receipts for temporary storage solutions
  5. Note any damage to vehicle roof as well

Accident Claims

  1. Include roof box in your accident report
  2. Note if contents were damaged or stolen at scene
  3. Provide evidence of proper installation (photos)
  4. Document that vehicle was within weight limits
  5. Mention if roof box contributed to accident (e.g., height restriction strike)

Permanent vs Temporary Installation

Most insurers distinguish between these two types of use:

Permanent Installation

  • Roof box stays fitted year-round or most of the year
  • Requires policy modification with small premium increase (typically £10-30 annually)
  • Modification stays on policy even when box removed
  • Best for regular users or permanent roof bar setups

Temporary/Seasonal Installation

  • Roof box fitted only for specific trips or seasons
  • Some insurers allow notification each time you fit the box
  • Often no permanent premium change
  • May require notification within 24 hours of fitting
  • Best for occasional users and rental customers

Best Practices for Insurance Compliance

  • Get written confirmation: Request written/email confirmation when you notify your insurer
  • Keep records: Save all correspondence about roof box modifications
  • Update annually: Confirm roof box details at each renewal
  • Remove when not needed: Take off roof box when not in use to reduce premium and theft risk
  • Use security measures: Locks and security bolts – insurers often require these
  • Take installation photos: Keep photos showing proper installation and security features
  • Document weight compliance: Note that you’re within vehicle weight limits
  • Review policy annually: Check coverage limits are adequate for your roof box value

Switching Insurers with a Roof Box

When getting quotes from new insurers:

  • Declare upfront: Always mention the roof box when requesting quotes
  • Compare like-for-like: Ensure all quotes include roof box coverage
  • Ask specific questions: Check coverage limits, excess amounts, and exclusions
  • Consider specialists: Caravan and motorhome insurers often have better roof box terms
  • Check contents coverage: Verify what’s covered in the roof box
  • Confirm temporary use: If you only use it seasonally, ensure insurer understands this

Conclusion and Key Takeaways

Notifying your insurance company about your roof box is a legal requirement that takes just a few minutes but could save you thousands in rejected claims. The cost is minimal – often nothing at all for temporary use – but the peace of mind is invaluable.

Key points to remember:

  • Always inform your insurer before fitting a roof box
  • Get written confirmation of notification
  • Expect £0-50 annual premium increase
  • Rental roof boxes still require notification
  • Car insurance doesn’t automatically cover contents in roof box
  • Use locks and security features to maintain coverage
  • Take photos of installation for future claims

Remember: a five-minute phone call to your insurer could be the difference between a straightforward claim and complete financial liability in the event of an accident or theft. Don’t risk it – notify your insurer today.

This post was written by

Founder, Rent My Roof Box

Frequently Asked Questions

Do I legally have to notify my insurer if I install a roof box?

Yes. UK insurers classify roof boxes as vehicle modifications — even when temporarily fitted. Not notifying your insurer can invalidate your entire policy, leaving you uninsured and personally liable for any damage or injury.

Most insurers charge little or nothing for temporary roof box use. Small permanent increases (£10–£50 per year) are typical, but many insurers apply no additional premium for occasional or seasonal usage when notified correctly.

Not usually. Car insurance rarely covers personal belongings kept inside a roof box. Those items are typically covered under home contents insurance, travel insurance, or specialist equipment policies — but only within specific limits and conditions.

Yes. A rented roof box still counts as a temporary vehicle modification. You must inform your insurer for the duration of the rental; otherwise, accident, theft, or damage claims can be rejected.

Insurers prefer clear evidence: installation photos, proof of purchase or rental agreement, details of locking mechanisms, itemised contents lists, and records showing proper fitting and weight compliance. Keeping these documented upfront makes future claims far easier.

Potentially, yes. Even short-term or one-off roof box use counts as a modification. If you don’t notify your insurer, they may treat any incident — even unrelated to the roof box — as uninsured driving and reject the claim entirely.

Most insurers only cover this under fully comprehensive policies and only if the roof box was declared beforehand. Some exclude damage caused by improper fitting, overloading, or low-clearance strikes, so you must check your policy wording.

Many insurers allow temporary or “seasonal” roof box declarations without permanent premium changes. However, you must still notify them every time you fit the box, unless they specifically note seasonal use on your policy.

Yes. Professional installation doesn’t remove your responsibility to declare the modification. Insurers care that the vehicle has changed — not who fitted the equipment.

Usually only under comprehensive cover, and only if you declared the roof box before fitting it. Many insurers require evidence of locked fittings and may exclude theft claims if the roof box was left overnight in a public car park.

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