spray application of an automotive underbody coating

Automotive underbody coating for protection from below

A lot of attention is given to the coating and paintwork of the visible aspects of a vehicle but those unseen places tend to get overlooked. The underbody is one such place. Automotive underbody coating protects a vehicle from everything the road can throw at it and more: they provide a layer of protection between a vehicle’s more vulnerable underside and damaging forces such as corrosion and moisture ingress. In this article we will outline the benefits and types of automotive underbody coating, and where you can find products and applicators in the US.


Car underbody coating protects the car undercarriage in 5 ways

If you have ever travelled in an old car down a gravel road you have heard the thunderous sound of hundreds of tiny pieces of rock being hurled at the underside of a vehicle. Not only is it deafening, it is also damaging. A car underbody coating:

  1. Prevents stone chip damage – A car underbody coating provides a durable elastic over the underbody and wheel arches which protects the substrate from stones, gravel, salt, and other debris which is thrown up by the road.
  2. Protects from corrosion – The automotive coating process consists of at least five layers of protective and decorative paint. However, the underbody only receives the first two layers – the layers that provide the corrosion protection. But if that is the case why would another layer of coating be needed to protect from corrosion? The initial two layers provide corrosion protection, but are not very durable. Stone chip damage may expose the metal itself, leading inevitably to corrosion.
  3. Prevents water ingress –  By covering cracks in the paintwork or joints in the undercarriage of a vehicle, moisture or water from humid or wet environments is prevented from creeping into the underbody and causing corrosion.
  4. Minimises sound – The noise of debris hitting a vehicle, or vibrations from the road can be dampened by the application of a car underbody coating. They prevent vibrations and because they are elastic they make far less noise when struck than the metal underneath.
  5. Is easy to maintain – Giving the undercarriage of a vehicle a uniform appearance means cleaning it down is simpler and so is identifying possible problems.

The 3 types of automotive underbody coating

Automotive underbody coating can be factory-applied or an aftermarket product. Most commonly these coatings are bitumen, resin, and wax based. The most suitable coating type is dependent on the required degree of protection, and the elements the car underside is likely to be exposed to.

man spraying car bottom with automotive underbody coating

Applying automotive underbody coating to protect the car underside.

  1. Wax-based: An excellent anti rust coating suitable for all substrates. The wax is applied soft and cures hard, either by brush or spray, and can be layered thickly. It cannot be top coated.
  2. Bitumen-based: These car underbody coatings provide hard-wearing protection against stone chip damage and corrosion. They also have sound-deadening properties. Suitable across many substrates, but cannot be painted over. Can be applied by brush or spray, high build, and good for very tough conditions such as off-road.
  3. Resin-based: Polyurethanes and rubber coating are popular because their elastomeric properties provide long-term stone chip damage and corrosion protection as well as sound deadening effects. These also have the benefit of being suitable for a wide range of substrates and they can be painted over. Can be spray-applied, high build, and particularly good for salted roads.

Car underbody coating availability in the US

The car underbody coating products for consumers are strictly aftermarket and dealer- or shop-applied. Dealers and automotive shops across the US provide these services alongside with applying other automotive coatings. The coatings themselves are provided by companies such as AkzoNobel, Henkel, Covestro, and Sika. The cost of an anti rust underbody treatment varies across vehicle size, as well as how much preparatory surface treatment needs to be done, and which coating type is to be applied.

If you want to know more about underbody coatings, or have a project that requires coating, get in touch! Our experts are ready to help, with collaboration from our coating partners. Just use the “Request a quote” button below and we will connect you with the coating solution for your needs.


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