Every year, Australians spend millions repairing rust damage on their cars. Moisture, salt, and rust are key factors in damaging a car, making it structurally weak and unsafe.
In the battle against rust and corrosion, undercoating emerges as a champion for automotive longevity. It is a protective layer applied to the underside of vehicles to safeguard it from damage caused by road debris, salt, and moisture.
Auto Bedliners offers a comprehensive guide on undercoating, exploring its types, understanding its pros and cons, and more. Read on to find out everything you need to know about undercoating for cars so you can make informed decisions about protecting your investment.
What Is Undercoating and How Does It Work?
Undercoating is a protective layer applied to the underside of vehicles to shield them from corrosion, rust, and damage caused by debris, salt, water, and other environmental hazards. It acts as a barrier between the metal components of the vehicle and the harsh conditions encountered on roads.
What else does undercoating do? Let’s find out!
Check out the list below for a brief overview of the functionality of undercoating:
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- Protects from rust—Vehicles are exposed to various corrosive elements, especially in regions where roads are salted during winter to melt ice and snow. The undercoating creates a barrier preventing moisture and other corrosive substances from reaching the metal surface of the vehicle, inhibiting rust formation.
- Dampens sound—The thick layer of material provides sound insulation by reducing road noise and vibrations, allowing for a quieter environment for passengers.
- Improves durability—Undercoating helps prolong an automotive’s lifespan by protecting its underside from corrosion and physical damage. It also prevents rust from spreading and weakening structural components.
Types of Auto Undercoating
The type of undercoating you choose depends on the vehicle’s intended use, environmental conditions, and the desired level of protection. Here are the most common undercoating types:
Rubberized Asphalt Undercoating
Rubberized asphalt undercoating is formulated from a mixture of rubber compounds and asphalt to form a thick layer that adheres to metal surfaces. It provides solid protection against abrasion and corrosion.
Wax-Based Undercoating
Wax-based undercoating is made with a blend of wax and corrosion inhibitors. When applied, the wax forms a flexible, water-resistant barrier to prevent rust formation. It is most effective for humid areas.
Petroleum-Based Undercoating
These are oil or solvent-based formulations that penetrate the pores of the metal substrate, displacing moisture and preventing corrosion.
Polyutherane Undercoating
Polyutherane undercoating is a high-performance option for extra resistance to abrasion, chemicals, and environmental factors. It forms a tough layer that sticks to metal surfaces for long-lasting protection and is used in heavy-duty applications.
Water-Based Undercoating
Water-based undercoating products are environmentally friendly alternatives and are made from water-soluble polymers and corrosion inhibitors. They offer good adhesion and durability.
Rubber Undercoating
Rubber undercoating is an adhesive formulated with rubber compounds that creates a flexible, waterproof barrier for harsh weather conditions. It is also resistant to abrasion and can withstand repeated flexing and movement without cracking.
How Much Does Auto Undercoating Cost?
The cost of undercoating a car depends on various factors, such as the type of product, size and condition of the vehicle, and whether the service is done by a professional or not. Here is a basic estimate you can expect to pay for undercoating:
| Type of Undercoating | Estimated Cost |
| DIY undercoating kit | Depending on brand, quality, and coverage, you can expect to pay between AUD 50 to AUD 150 for a DIY undercoating kit |
| Professional undercoating services | Auto repair shops provide professional undercoating services ranging between AUD 150 to AUD 500 |
| At dealerships | Dealerships usually charge approximately AUD 800 to AUD 1000 for undercoating |
Some undercoating services also include additional treatments, such as rust removal, surface preparation, or corrosion inhibitors, increasing the overall cost. When getting quotes from professionals, make sure you inquire about all additional services included in the price.
Difference Between Rust Proofing and Undercoating
While rustproofing and undercoating both protect vehicles from rust and corrosion, they serve slightly different purposes. Check out the table below for the key differences between rustproofing and undercoating:
| Rustproofing | Undercoating |
| Rustproofing prevents rust and corrosion on the exterior surfaces of the vehicle, including body panels, doors, hood, trunk, and fenders. | Undercoating is designed to protect the underside of the vehicle from damage and corrosion. It is applied on the frame, floor pans, wheel wells, suspension components, and all other exposed metal surfaces beneath the vehicle. |
| Rustproofing treatments penetrate the surface of the metal to create a protective barrier that inhibits rust formation from inside and outside. They contain corrosion inhibitors that chemically bond with the metal to provide protection | Undercoating provides a physical barrier against external elements and does not penetrate the metal. |
| Rustproofing requires periodic reapplication to maintain effectiveness. It also requires regular inspection to identify any areas where the treatment may have worn off | Undercoating also requires frequent maintenance to ensure continued protection |
To summarize, rustproofing and undercoating complement each other to protect a car from corrosion, with rustproofing focusing on the exterior surfaces and undercoating targeting the underside. Both treatments are vital to preserve the structural integrity of the car.
Steps To Undercoat Your Car
You can effectively undercoat your car yourself if you don’t want to hire a professional for the job. All you have to do is follow the steps mentioned below:
- Prepare your car—Park it on a flat, level surface. Allow the underside to cool down before cleaning it thoroughly with a pressure washer and wire brush to remove dirt, rust, or old undercoating.
- Choose the undercoating material—Select the appropriate type of undercoating. When choosing the material, consider essential factors, such as weather conditions, ease of application, and the level of protection you want.
- Apply the undercoating—Shake the undercoating product properly before opening it.. Use an undercoating gun, spray gun, or brush to apply the product evenly. Start from one end and work your way to the other, applying a consistent layer to all exposed metal surfaces. Pay close attention to all areas prone to rust.
- Allow the undercoating to dry—Give the undercoating sufficient time to dry, which can take anywhere from a few hours to a whole day. Avoid driving the vehicle or exposing it to moisture during this time.
- Inspect and maintain—Once the undercoating has dried, inspect the underside for any missed spots. Make sure you have adequately and evenly covered all exposed metal surfaces.
Before you start, use plastic sheets and masking tape to cover any areas you don’t want to be coated. This will prevent overspray and ensure a clean application.
Pros and Cons of Auto Undercoating
While undercoating your car can offer several benefits, there are also potential drawbacks to consider. Check out the table below to weigh the pros and cons of auto undercoating:
| Pros | Cons |
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Is Undercoating Your Car Worth The Effort?
Whether you want to undercoat your vehicle depends on the following factors:
- Weather conditions—If you live in an area with high humidity, harsh winters, and frequent rain, your car is more prone to rust and corrosion. Undercoating will provide an extra layer of protection, making it more beneficial.
- Road conditions—Frequent drives on gravel roads or rocky terrain can cause more damage to your vehicle. Undercoating can help shield vulnerable components from impacts and abrasions, prolonging the lifespan of your car.
- Vehicle condition—Older vehicles or those with existing rust can benefit from undercoating to prevent further deterioration. New cars can also take leverage from undercoating to avoid early corrosion.
- Cost of repairs—Compare the cost of repairing rust-related damage with the upfront cost of undercoating and see which one is more likely to fall in your budget. In most cases, investing in undercoating saves money in the long run by preventing costly repairs
- DIY vs. professional application— You can apply undercoating as a DIY project or hire a professional to do it. While DIY jobs are cheaper, professional mechanics ensure proper preparation, coverage, and quality.
Misconceptions About Automotive Undercoating
There are a lot of misconceptions about auto undercoating that may lead to unrealistic expectations. We have addressed the most common ones below
- Undercoating is permanent—Even if you use the best material for the job, undercoating does not provide a permanent solution to rust. Over time, the effect wears off due to exposure. It is necessary to carry out periodic maintenance checks to ensure continued effectiveness.
- Undercoating fixes current rust—Undercoating is a preventative measure and does not treat existing rust damage. Applying undercoating paint over rusty areas can temporarily hide the problem but will not stop the corrosion process. It is essential to treat corrosion before applying undercoating paint.
- Undercoating makes vehicles impenetrable to rust—Undercoating significantly reduces the risk of rust, but it does not make vehicles impervious to it. Factors such as weather conditions, driving habits, and maintenance practices affect the performance of undercoating.
- New cars do not require undercoating—Although new cars are already undercoated, it does not provide enough protection especially if you’re living in harsh weather conditions. Additional layers will help protect your vehicle more.
- Undercoating is expensive—Undercoating cost depends on the type of material used and the inclusion of additional services. Compared to potential repair damage from rust, it is still cheaper than hiring a professional.
Protect Your Car From Damage With Auto BedLiner’s Undercoating Services
Discover the ultimate protection for your car with Auto BedLiner’s car underbody protection coatings.
Our vehicle rust protection specialists are experts in applying undercoating on your car to protect it from all kinds of damage. We will inspect the car thoroughly to provide you with the best possible solution for your undercoating requirements. Our top-notch undercoating material will ensure that your car stays protected even in the harshest of weather.
Schedule your appointment with Auto Bedliners today!
