Underbody Coating
UNDER-BODY COATING
A car’s underbody is exposed to the most wear and tear caused by muddy water, potholed roads, stones and other obstacles on the road. Because it’s not in plain sight, we often do not see the damage.
Under body protective coating is used to protect the vehicle chassis from external environment, to ensure the integrity and safety of car. The use of underbody coating plays a very important role in the service life of the vehicle. In general, it is required to spray such a protective coating in the manufacturing of the new car. Due to the highly competitiveness of new car sales, car producers have pressure to reduce the manufacturing cost, so that they reduce or even completely eliminate the use of under body coating where it is not to be easily seem by car owners. As a consequence, our car service life will be greatly reduced.
Before coating After coating

PURPOSE OF UNDERBODY COATING
- Prevent from stone chip
There are thousands of pieces of stones on the road, and they are constantly hitting your car on the under body, wheel arches, sills and the trunk lower part while driving on the road. In some cases, the under body might be scratched by uneven road. As such the thin corrosion protection coating on the metal sheet will be destroyed and leave the bare metal exposed to the air, which will soon come to corrosion when contact with the moisture in the air. If not promptly getting anti-rust treatment, then the rust will soon spread to large areas. Under body coating or the anti-stone chip coating is a thick elastic layer which could not be easily damaged by stone chipping or scratch, therefore could basically protect the metal sheet of the under body.
- Prevents Paint Chipping
Running on the highway or while pacing through a city road, you will often encounter sharp gravel or any other unattended object hitting the belly of your car with high momentum. This scrapes and chips off the metal from down below. A thick layer of Underbody Coating definitely comes to aid and minimises the effects of such contacts on the body.
- Protects Against Rust & Corrosion
The primary objective of getting underbody coating done is preventing metal components that are exposed on the bottom side of the car to damage from corrosion. You can shut out the Adverse effects of corrosion on your car by simply applying a rubberised anti-rust coating all over the belly of your car.
- External influence
External environment, such as the baking from the hot road in summer, the road’s anti-frozen gent in winter, raining water and the salty water in the atmosphere, will attach the under body of a car. Particular in coast areas, the wind from the sea will bring more salt to the air, which will accelerate the corrosion and reduce the service life of a car. While the under body is covered by the thick and tight layers, it would act as a strong barrier to prevent these external substances attaching the metal sheet.
- Protects Vital Components
Underneath a car is somewhere a lot of indispensable parts of a car are left exposed like the Engine, silencer, etc. One simply can’t afford to let these parts go bad due to rusting and hence in order to save yourself from a hefty repair bill, a considerably less expensive Anti-Rust Coating is a must.
- Keep the value
A car could keep a high value while it is well maintained. It means that if a car is well treated on under body protection, it could keep the car in a good condition and extend the car’s service life, or you could charge a higher price in a used-car trading.
- Reduces NVH (Noise Vibrations Harshness) Levels
Our country is filled with roads having uneven patches and potholes and while we manoeuvre our cars through such sections, the unpaved crumbs, and pebbles hit the car from underneath or get stuck in the wheel wells. The underbody coating’s consistency is so thick that the layer it creates absorbs all the unpleasant noises and vibrations and marginally improves the driving experience.
TYPES OF UNDERBODY COATING
When having your vehicle rustproofed or an undercoating applied, you have a few options to choose from. Whether you prefer the latest technology or a more tried and true method, knowing what the different options are should allow you to choose the best one for your vehicle.
- Rubberized Undercoating
Rubberized vehicle undercoating is easy to apply and offers sound-cushioning as well as protection from dust, moisture, and dings or dents.
In addition to your undercarriage, rubberized undercoating is also safe to use on wheel wells and quarter panels, and dries to a soft rubbery finish that prevents further rust, damage, or moisture seeps. The coating can be painted over and, if necessary for bodywork, can be easily removed with an undercoating removal spray.
Overall, rubberized coating is generally the best option for protecting your vehicle's undercarriage, as it provides the simplest and best protective measures against rust and moisture.
- Polyurethane Undercoating
The other option for undercoating your vehicle is to use a polyurethane-based sealant. This type of vehicle undercoating is a little bit quicker and easier to apply.
Oftentimes, polyurethane undercoating will come in canisters ready to preload into an application gun. This type of sealant works by seeping into all cracks and seams, displacing salt and moisture and oozing around rusty areas to bond with and protect unoxidized metal. It also sands quickly in case you'll need to perform bodywork and can be painted over.
On the flipside, this type of car undercoating generally requires a little bit more surface prep work before applying -- sanding and applying an etching primer to bare metals before using are generally recommended.
- Wax or Paraffin-Based Undercoatings
A paraffin-based undercoating will be the cheapest and quickest option available with which to protect the undercarriage of your vehicle. However, keep in mind that it will wear off quicker than other types of undercoating and will need to be stripped and reapplied at least once every year.
Wax-based undercoatings never truly harden. During application, they drip or flow into seams and cracks to provide protective properties. They are usually available in a spray gun canister or in an aerosol can and offer at least a base protection in moderately humid climates.
- Asphalt-Based Undercoating
For standard vehicles, any of the aforementioned types of undercoating will provide sufficient protection. For large trucks and heavy machinery, asphalt-based undercoating provides a bit of extra durability against rocks, chips, and moisture.
Asphalt-based undercoating generally contains a little bit of rubberized material that sets up firmly and also helps soften noise. Generally sold in five gallon containers, this type of undercoating also needs more cure time than the other three, and is NOT paintable, making it best to use only for undercarriages.
ADVANTAGES
- It provides a layer of protection against corrosion.
When an undercoating is properly applied to a vehicle, then you’ll be providing the underbelly with a layer of protection against rust and corrosion. Instead of contacting the metal components of the vehicle, the debris encounters the undercoating, which then proactively repels the dangerous items away. Although an undercoating will eventually wear out, it can provide years of protection against premature corrosion.
- It will extend the life of your vehicle.
A proper undercoating extends the life of your vehicle because of its rust-stopping power. Corrosion does more than affect the integrity of the metals in your vehicle. It can get into your metal wires and cables, affecting any component which is comprised of steel or aluminium. Even your transmission and engine have exposure to rust when there isn’t a vehicle undercoating applied.
- It can be applied to damaged areas.
Over time, the underbelly of your vehicle is going to develop nicks, chips, and scratches because of the debris you encounter while driving. Unlike older forms of undercoating, which included the use of asphalt and animal fat, modern products provide a real layer of protection because it can morph into the various areas of small damage.
A modern undercoating is usually wax-based, which creates a living barrier that your vehicle can use to promote a self-healing experience.
- There are multiple undercoating methods which can be used.
There are four different undercoating methods that are commonly used on vehicles which require this service. The electronic method is used when rust is present to stop its corrosive effect, which is a method that receives mixed reviews. A standard undercoating method applies a tar-like substance to the exposed components of the vehicle underbelly. A dripless oil spray applies a waxy substance that fills in the entire body of the vehicle, which hardens when it dries.
Then there is the drip-oil method, which may cause dripping for up to 48 hours when applied. From a cost perspective, it is this final option that is most often applied at the dealership.
- It may help to reduce interior noise.
When you’re driving, the sounds of the road can be soothing if they aren’t too loud. For lightweight vehicles, the noise pollution can be overwhelming to the driver in some situations. Applying a layer of undercoating creates a barrier against the sound, which creates an interior that is quieter. After the service is performed, many drivers notice that audio levels are noticeably lower inside their vehicle.
DISADVANTAGES
- It won’t do anything about the corrosion which is already present.
For an undercoating to be effective, it must be in place before the underbelly of your car begins to rust. If you apply it over corrosion, you won’t be making an improvement. It will look better… until the rust breaks its way through the layer of undercoating you’ve applied. If you have rust present, then it must be removed, with the metal repaired, before the undercoating is applied for best results.
- It works best on new cars.
If you’ve purchased a used vehicle, then the cost of preparing the underbelly for an undercoating might be more than the value of the car. You must remove all the residue from the bottom before it can be applied. Failing to do so will seal in the debris that is present already, which can lead to more problems. The best time to have an undercoating applied is when a vehicle is purchased new because it offers a superior level of protection then.
- It adds weight to the vehicle.
Although the amount of weight added to a vehicle with an undercoating is minimal (between 10 to 20 pounds for most vehicles), there is an element of fuel economy to consider. When your vehicle weighs more, the distance you can travel on a single tank of fuel is reduced. The undercoating might reduce your efficiency by up to one mile per gallon, which creates an additional fuel cost over time that is worth considering.
- An undercoating is not impervious to damage.
An undercoating can provide a hardened layer of protection against dirt and debris that may cause corrosion. Depending on where you drive, however, the lifespan of this product may be minimal. If you drive your vehicle on gravel roads or dirty areas frequently, you reduce the integrity of the protective layer.
You might find that your undercoating begins to chip off in as little as 25,000 miles because of this issue. Driving in a salty environment is not the only threat to the integrity of this product.
- It must be reapplied every 3 to 5 years for best results.
The only way for an undercoating to provide ongoing protection for your vehicle is to have the service repeated frequently. Most owners can have a new layer applied in about 5 years without worrying about their underbelly being compromised. In salty or destructive environments, however, you may need to have a new undercoating applied every 3 years for best results.