Has your car been involved in an accident and suffered damage to its underlying structure? If it has, it may be considered a car insurance write-off. 

One of the most frequent forms of damage, a Category S write-off is also one of the least severe. It's slightly more serious than Category N, but it can sometimes lead to your car being written off by your insurer. 

But what is a Cat S write-off? Read on to find out what damage causes your car to be designated as such, and how it could affect your insurance. 

What is a Category S car?

Formerly known as Category C, Category S is for vehicles that have received structural bodywork damage - a bent chassis or creased door frame, for example - but can be repaired and put back on the road. 

While a Category S write-off is among the least severe, it still means a vehicle will be deemed unsafe for use until it has been professionally repaired. 

What damage will a Category S car have? 

Unlike Category N write-offs, a Category S car will have suffered damage to its structure. This can include damage to parts such as the chassis, which may have become twisted or bent, the suspension, crumple zones, bumpers and wing supports. 

According to the Association of British Insurers and repair firm Co-Part, areas of your car considered structural include the following: the firewall and front bulkhead, side cant rail, rear crossmember, rear inner wing, rear header rail, rear wheel-housing extension, B-pillar, sill, front upper-wing support, front inner-wing support, A-pillar, front chassis leg/welded crossmember and rear chassis leg. Damage any of those parts and you could be looking at a Category S write-off. 

A Category S car can be repaired safely, but they have to be re-registered with the DVLA, unlike Category N cars. Repairs will also cost more than the vehicle’s market value. 

If it looks like the cost to repair the car will surpass 50% of its value, the chances are an insurer will write it off. 

Should I buy a Category S car? 

Several dealerships do sell cars that have been through a Category S write-off. While they’re not necessarily unsafe, there are several things you should consider before you buy one.  

Any Category S car should be properly examined by a trusted mechanic or engineer before you buy it. They will then decide if it lives up to DVLA standards. A Category S car will also need to pass an MOT before it can get back on the road, and the DVLA must be told about it. 

If you do want to buy a Category S car - and there are big savings to be made by doing so - you should complete an HPI background check on the specific vehicle. You should also check all the repairs were done to a professional standard. 

It’s important to note that while a Category S car might be cheaper to buy, it will also be harder to sell and will not be worth as much as a well-maintained equivalent. 

Can you insure a Category S car?

You can insure your Category S car, but only if it has been fully repaired. It’s also likely to be more expensive than a car that hasn’t been written off, because it is deemed to be a much higher breakdown risk. 

Other write-off categories

In the UK, there are four different categories for insurance write-offs.

Category N is the least severe and is for non-structural damage. Next is Category S, for more serious structural damage that can be repaired. 

Category B is the second-most severe form of write-off. It is used to classify vehicles with extensive damage - be it structural, electrical or mechanical - and cannot be repaired.

At the top of the scale is Category A, which is reserved for the most costly and severe write-off, where the entire car will be sent straight to the scrapyard. Often, the majority of the car's parts will not be serviceable. While most Category A designations are caused by accidents, they can also be caused by vandalism and complete burn-outs.