How to apply asphalt based sound deadening material to your car

This guide covers the basic method for applying this peel-and stick material and then tell you how, where and why to apply it.


The application of sound deadening material to your car is a very effective way to make your driving experience more comfortable. It will serve to keep out road and engine noise and keep the sound from your stereo inside the car. Asphalt based sound deadening generally comes in peel-and stick panels. This guide covers the basic method for applying this peel-and stick material and then tell you how, where and why to apply it.
Applying asphalt-based sound deadener is actually quite simple. Begin by removing any interior trim panels so that you have unobstructed access to the bare metal panels that you will be applying the material to. Before you do anything else, clean the surface well using an alcohol based cleaning product that will not leave a residue. Then, start by forming the material to the contours of the surface before you remove the adhesive backing. Using a heat gun or a high-powered hair dryer, heat the material and press it into the grooves of the metal until you are satisfied that it is in full contact with the floor. This is also a good time to trim the piece to fit and cut holes for any bolts or hardware that you may need access to. Allow the piece to cool, then pick it up and remove the adhesive backing. Line it up with the contours, then place it down gently. At this point do not try to adhere the whole piece at once. Instead, use a narrow roller to work from one side to the other, pressing the piece down into every contour. It may help to use the heat gun during this process. Any air bubbles after the piece is fully adhered should be poked through with a sharp blade, and then rolled out for maximum contact. If you need extra deadening, you can layer the material as many times as space will allow.

Trunk: If you have a subwoofer in your car, it is especially important to apply sound-deadening in the trunk. If you do it right, it will prevent annoying rattles and keep the sound pressure level from the sub from escaping through the trunk. Many manufacturers sell kits that contain a good amount of material for covering your trunk.

You should begin the application in the spare tire well and on the metal floor of the trunk. Work from one side to the other to avoid overlapping, and be sure not to cover up any hardware that will be necessary to secure the spare tire or the cargo floor. When you have finished the floor, peel back the carpet on the sides of the trunk and apply material there. If there are holes cut in the metal, you should cover these up if you do not think you will need access to them in the future. For the trunk lid or hatchback door, remove the panels to gain access to the metal inside. Apply liberally here, as sound tends to rise, but be sure that the extra weight of the material will not counteract the shocks that hold the trunk lid open.

Doors: Sound deadening the doors of almost any car will result in a noticeable improvement in sound levels, especially if your front speakers are located in the door. Not only does most of the road noise come in through the door, but the flimsy sheet metal of the door also acts as a poor acoustic surface, creating distortion in the sound of your stereo.

To counteract this, apply sound deadening to the metal inner skin of the door. You don’t necessarily have to cover everything, but be sure to get the holes and the thinnest parts of the sheet metal. The most important part of the door panels is the area surrounding the speaker. If you have enough clearance from the interior panel, apply a few layers here.

Floor: Applying a sound deadening material to the floor of your car will probably not help make your music any louder; however it will significantly reduce road noise and allow you to hear music and people in your car more clearly.

If you are going to deaden the floor, buy enough material to cover the entire metal. This is an involved process, since you probably should take out your seats and carpet in order to gain access to the whole area. The areas to focus on here are the fenders and the surrounding metal since most of the noise comes from the tires. While you’re doing the floor, it is a good idea to apply material to the engine firewall as well. This will reduce engine noise in the cabin.