Does Spraying Rubber Soundproofing Reduce Noise Significantly

With current technological advancement in the vehicle manufacturing industry, cars have become a lot more pleasant to drive, even on noisy highways. Still, it’s hard to ignore that constant buzzing of the road beneath you and the wind whizzing past your windows. Fortunately, those who have been pushed to their wit’s end by all this road noise have many solutions to choose from to get rid of this annoyance.

Rubberized soundproofing spray can reduce road noise by a minimum of 5dB. This is not a significant noise reduction since the human ear can only begin to pick up audible changes when there is a difference of 3dB.

The extent to which the application of rubber soundproofing is effective depends on the application, the road being driven on, and the driver. Many people have misconceptions about what to expect from soundproofing solutions, as they do not understand that the sound should not go away entirely. To ensure that your expectations of rubber soundproofing spray are realistic here’s some information on what effect this solution has on your vehicle.

Does Rubberized Soundproofing Reduce Road Noise?

Does Rubberized Soundproofing Reduce Road Noise

When you apply rubberized undercoating on your vehicle, you will be reducing the noise by a minimum of 5 decibels (dB). (One test conducted on city streets demonstrated that the difference reached almost 10dB.) However, to humans, that change does not seem like a lot since the threshold for noticing changes in audio is just beneath about 3dB

The noise reduction achieved by applying a soundproofing solution can make your road travel significantly more peaceful. Still, it’s tough to determine whether this is “significant” or not. Concerning the threshold for the human ability to detect notable changes in volume. Yes, soundproofing does reduce the noise that enters the cabin of the vehicle quite significantly. On the other hand, some people may not be happy with only a slight change.

One bonus that rubber soundproofing spray has over other noise-reducing alternatives is that it protects your vehicle from wear and tear on the road as well. The coating shields the undercarriage from the following elements that can harm your vehicle while driving:

  • Metal parts from construction sites or broken vehicle components 
  • Hazardous waste and trash
  • Small rocks 
  • Salts and chemicals used to treat asphalt roadways

This rubber barrier prevents rusting and general degradation while the spray remains intact over time. For some, the noise reduction is not enough on its own, but this certainly adds appeal.

Part of the issue with determining whether this change is significant or not is the widespread lack of understanding of what exactly soundproofing is meant to achieve. To better appreciate the goal of spraying rubber soundproofing on your vehicle’s undercarriage, you must first grasp the mechanisms behind the noise produced by your car and how soundproofing will stop it. 

[Related Article: Soundproofing A Car In 4 Simple Steps]

What To Expect When Soundproofing Your Vehicle 

What To Expect When Soundproofing Your Vehicle 


Sound is a type of energy that is produced by vibrations in the atmosphere. When a source vibrates, the frequency of that vibration is carried through the air into your ear. The frequency travels all the way through the canal and onto the bones that create the noise on the eardrum, allowing you to interpret what you register as “noise.”

Why does any of this matter? The key here is the vibration. As your car is traveling along the road, it is vibrating not only as a result of the rapidly turning wheels but the friction along the road as well. As you may have observed, the pavement that comprises streets and highways are not silky smooth, but are instead, bumpy and gravely, hosting a layer of light debris as well. a

As your car travels across this surface, it produces vibrations as a result of the contact the tires make with the pavement’s imperfections. (This is why, as you may notice, certain roads are much louder than others as you drive through neighbourhoods and across highways.) With all of this said, you cannot reasonably expect that the soundproofing will eliminate all road noise. If it did, the vibrations that reverberate through the vehicle’s body would have to be stopped as well.

When you apply rubberized soundproofing spray to your car’s undercarriage, you are more so installing a sound-absorbing mechanism. Rubber materials are known to absorb incoming energy, so the area being protected experiences reduced vibrations, and therefore, less noise. This means that you will still hear the road noise in the cabin, since it cannot be tremendously reduced, given the thinness of the layer of rubber that is applied. 

[Related Article: How To Soundproof Your Expensive Tractor Cab – A DIY Guide]

Applying Rubberized Undercoating to Your Vehicle

Now that you know what to expect, you can confidently proceed in your endeavors to reduce the road noise produced by your vehicle. Applying a rubber soundproofing solution to your vehicle is very straightforward. It can be done by yourself at home, or, even better, you can take your car to a mechanic to have the job done. (Who knows, they may apply techniques that reduce the noise even more!) 

If you choose to do this yourself, however, simply follow the instructions below:

  • Clean the undercarriage of your vehicle using a pressure washer. (If you neglect this step, the spray will not adhere correctly and provide minimal noise-reducing effects or protection for your car.)
  • Take your time and apply an even layer of rubber soundproofing over all the components located underneath your vehicle.
  • Typically, this is best achieved by using a spray gun. A disposable spray gun is best since a reusable gun will be difficult to clean, even if you use only a small amount of solution.
  • Give the new coat of rubber spray adequate time to dry and set. The setting time will depend on the environmental conditions at the time of application; however, allow at least 24 hours.

For the maximum protection against both noise and harmful materials that can be kicked up by the road’s surface, apply two coats of the rubberized soundproofing. This will reinforce the effects of the coating and ensure that any spots that may have been missed in the first layer are now taken care of. (If you choose to apply two or more coats of rubber soundproofing, it would be best to extend the setting time to 48 hours.)

Rubber Soundproofing versus Sound Deadening Undercoating

As you search for the best soundproofing solution for your vehicle, you may notice that this product is often compared to another known as “sound deadening undercoating.” The two have very similar purposes, although many believe that sound deadeners are more effective at reducing the vibrations mentioned earlier. Of course, this is a matter of opinion and application technique. 

When applied by experienced mechanics, rubber soundproofing can make a significant difference in the noise detected in the cabin. If someone were to do it themselves with minimal experience in such product applications, the result is likely to be unimpressive when compared to a similar product. 

Some will claim that rubberized soundproofing spray does not reduce vibrations at all. This is false, as this is precisely the purpose of using rubber material in noise reduction. What these arguments typically mean is that deadeners may be more effective at reducing vibrational sound. Sound deadening undercoating is also capable of providing thermal insulation, whereas this is not a feature of rubber soundproofing.

Additionally, spray-on rubber soundproofing will protect the vehicle against damage from impacts as well, whereas deadening undercoating will not. Your decision as to what solution would be ideal for your vehicle will depend on what type of driving you will be doing, and the extent of the desired noise-reduction and protection required for the car. 

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