How to Sound Deaden a Car

How to Install Sound Deadener in a Car

Author: Eric Zuck

Last Updated: February 9, 2024

Read Time: 7 Minutes

How to Install Sound Deadener in a Car


Eric Zuck

Last Updated:

February 9, 2024

Read Time:

7 Minutes

Author: Eric Zuck

Updated: Feb. 9, 2024

Read Time: 7 Minutes

Heat shields rattle because the welded sheet metal car manufacturers use can rust or come loose after years exposed to the elements and daily wear and tear. The result for you is an annoying heat shield rattle that drives you a little bit crazy every time you reach a certain RPM.

Thankfully, there are some tricks to make it a quick and inexpensive fix. Before getting started, there are a few things to know:

  • Heat shields are important. Don’t just rip off a rattling heat shield. Although you can technically still drive your car or truck without a heat shield, it’s a needed safety feature that was put on your car for a reason.
  • It’s easy to find the source of the problem. We’ll go into more detail on this in a moment, but for now, know that fixing your heat shield rattle isn’t a multi-day operation. You should be able to find the problem and fix it yourself.
  • Some cars are more prone to heat shield rattling. Not all manufacturers use the same materials or weld with the same processes. Although no car is immune to heat shield rattle, older cars and lower-end models are more likely to have this issue.

Installing Sound Deadener in a Car

When we are asked how to sound deaden a car, our first reaction is that it's both very complicated and very simple. The hard part is knowing the best use for the variety of materials available to you. Should I be using a sound deadening mat or a spray on sound deadener? Does sound deadening work in cars? (Yes if done right). When should I use foam and when should I use a mass loaded vinyl? Should I just go with the cheap sound deadening that's made of asphalt? (DON'T DO IT!)

We know you're likely to have questions whether you're a pro trying a new deadener install strategy or someone who just wants to fix a car with a frustrating amount of road noise. That's why we've created a ton of resources for you to educate yourself and make the best decision for you, like this article on how to soundproof a car.

If you're past all that research and you just want some quick tips on how to apply sound deadening, the most straightforward part of installing sound deadener is the actual application of the material. If you scroll to the bottom, we've also included a Sound Deadener Install FAQ that gives tips and tricks you can use to save time and money.

Step 1

Remove upholstery to expose the bare sheet metal. This can be a challenge if you'e never done it before (use YouTube). Ensure there's no debris, rust, or waxy oils. Clean the surface with denatured alcohol.

Step 2

Cut sound deadening material to the desired size using a sharp utility knife. For smaller surface areas, measure dimensions and cut to fit.

Step 3

Peel off the paper liner and adhere to surface. Roll on with a hand roller to remove any air pockets and ensure a proper bond.

That's all there is to it. Seriously. For those of you that are visual learners, check out several videos will pulled from the archive of pros installing Damplifier Pro.

Second Skin: Overview of How to Sound Deaden a Car

SaabKyle's 240SX: Full Car Sound Deadening Installation

Mark (CAF): Installing Sound Deadener & MLV on a Door


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Popular Sound Deadening Material

Damplifier Pro™ Deadening Mats
Damplifier™ Deadening Mats
Spectrum™ Spray on Deadener

Sound Deadening Install FAQ: Tips & Tricks

What Tools Should I use to Install Sound Deadener?

  • Hand roller: We recommend a smaller roller to get into tighter areas. We sell a wooden one, but have also used rubber rollers we've liked. We prefer not to use metal rollers as they can tear the material.
  • Utility Knife: Use the utility blade to cut the material. Keep the blade sharper for longer by cutting on the mats on a piece of cardboard. Have some extra blades handy for a big job.
  • Gloves: The thick, annealed foil is sharp on the edges. If you've never installed a sound deadening mat before, definitely wear gloves.
  • Denatured Alcohol: Apply to a rag and use to clean metal surfaces prior to installing.

Depending on how precise you want to be, you may also want to create templates or trace with a sharpie and a ruler prior to making any cuts. This is not necessary, as the material is often covered, but can result in a cleaner looking install.

We sell both the utility knife and the wooden hand roller together at a discount in our Sound Deadening Mat Tool Bundle.

How do You Apply Sound Deadening Material?

We sell our Second Skin sound deadening mat products in easy-to-work-with sheets. If you can measure, peel, and stick you can install Damplifier™ and the twice-as-thick Damplifier Pro™ sound deadening mats. You’ll want to apply pressure with your hand to position the mat, and then use one of our wooden hand rollers to stick it down firmly to the metal surface.

If you're applying a whole sheet, some customers find it easier to peel back a small portion of the release liner at a time and work their way across the panel. For tight areas where space is limited, cut the sheets into smaller pieces to make them easier to work with.

Always remove air bubbles with your hand roller. Besides the quality of the material, the #1 determinant of vibration damping is the quality of adhesion to the application surface. You want the mat to be firmly adhered.

Where to Sound Deaden In a car?

The areas of your car you should soundproof by applying deadener are:

      • Doors - This will reduce any rattling panels inside your dar, and often helps a lot with improving the audio quality and performance in your car
      • Floor - Applying sound deadening and a sound blocking layer to your floor will reduce noise from entering into your cabin.
      • Trunk - If you have a lot of sound coming from tires or speakers in the trunk, applying sound deadening will help.
      • Firewall - This helps reduce sound transfer from the engine into your cabin area, as well as stops heat transfer
      • Roof - This will help reduce sound coming through your ceiling on rainy days, and will make your overall drive quieter.

Our sound deadening materials can be applied directly to all types of metal. All Damplifier™ sheets use a very strong adhesive, so they can even be applied straight to fiberglass, plastic, and wood surfaces, although those materials don’t tend to vibrate as much as sheet metal or aluminum. You can make a meaningful difference in structural noise to all of your vehicle's metal surfaces: the doors, floor pan, trunk, firewall, hood, and roof. Since there's no trunk in a truck, truck cab sound deadening becomes extra important!

As far as priority, most sound deadening installs should prioritize the doors, the floor, and the trunk. That means starting all the way up from at the firewall and working your way back (make sure to hit those wheel wells along the way!).

How Much Surface Area Should You Cover?

To deaden the metal, you must cover at least 25% of the surface with the Damplifier™ mats. We recommend 60% coverage with a focus on covering all the flat metal panels, because the curved parts of the car tend to be more structurally sound. Another effective strategy is the "checker board approach" where you cut the mats into smaller pieces and apply to the surface in a pattern that looks like a checker board.

Many customers choose to cover as close to 100% of any metal surface as possible, either because they also want to thermally insulate their car, they like the way it looks, or they just want to max out their results while they have the interior of their car on the floor of their garage. Going with 100% coverage as an mlv alternative will give you less results than using the MLV as a sound blocking layer, but will perform better than only 60% coverage

For parts of the car you want to thermally insulate (usually the roof, outer door skins, firewall, and hood), we go for as close to 100% coverage as possible on our own installs. It can be worth it on the floor too if you have a high performance exhaust system or other thermal hot spots.

How Do You Ensure the Sound Deadener Sticks Well?

Second Skin sound deadening mats create a very strong bond with sheet metal; it’s honestly hard to make it NOT stick. To ensure the best bond, we strongly recommend cleaning the metal surface first and then using a hand roller to firmly attach the mat.

Good adhesion without air bubbles is absolutely key if you want to get the best performance. Every pocket of air or poorly adhere sheet means you're sacrificing damping effectiveness.

How to Install Sound Deadener: Quick Recap

  1. Start by removing the upholstery and carpet from your car. Vacuum the entire area to remove loose debris and dirt. Then clean any greasy spots with denatured alcohol. If you use another solvent or degreaser, you may leave behind a film that will prevent a solid contact surface. Allow the metal to dry.
  2. Cut Damplifier mats to the desired size with a sharp utility knife. We recommend wearing gloves because the foil edges are sharp.
  3. Peel the wax paper liner from the back of the mat, and adhere the tacky butyl side to the sheet metal. Slowly work the Damplifier onto the panel with a hand roller to ensure it bonds.

If you want to learn more about other soundproofing materials you can use in combination with Damplifier, take a look at our Installation Guide. You can also give us a call and we'll be happy to help out.

Complementary Soundproofing Materials to Consider

Combine Your Sound Deadener WITH Sound Blocking Material

Have you ever closed the door to a luxury vehicle and felt the world go silent around you? That’s why we recommend that you combine Luxury Liner Pro automotive noise barrier with your sound deadening material. Using the two products together will create an airborne noise barrier that's an incredible complement to the sound deadener damping the car's structural noise.

The Final Result: Luxury Car Silence

Reduce UnderHood Heat and Sound

No problem. Damplifier and Damplifier Pro will handle up to 450 degrees Fahrenheit, which is a 50% higher temperature rating than many of our competitors’ products, and plenty high to go on the inside of your firewall.

While the thick foil, butyl rubber combo in Damplifier serves as a radiant barrier and reduces thermal transfer, sometimes you need additional heat insulation. If you need even more thermal protection (or just want to replace your hoodliner), check out Mega Block, our best automotive heat shield.

Curious? Well... We've Got a lot More Soundproofing Material to Choose From

Ahhh... so ARE at least a little curious! Maybe just a quick peek at what else Second Skin has to offer? Why else would you have made it all the way down here? This is a long page!

That's how it always starts. You thought you were just going to nab some pro sound deadening tips, and next thing you know you have the itch to check out what else you can do to make your ride cool and comfortable. We have many different vehicle example on our customer projects page, and also have specific car article like our honda accord road noise or our Tesla Model Y road noise articles.

A good place to start is our Owner's Manual. We've got guides galore in there. Or you can just reach out to us and we'd have a good time talking to you about your build.

Have questions about your project?

Call us at 1.866.570.5440