How to Use Insulation to Deaden Sound in a Car

To avoid potential hearing damage, sound proof your car.

Factory sound-proofing simply does not do the job. Road noise and engine sounds make their way into our cars through the floor boards and fire walls. This can affect the quality of sound we get from our stereo systems and make a long trip very uncomfortable for the passengers. The solution is a relatively simple installation of an after-market sound deadening material. This material can be found at most better automotive supply stores or building supply outlets. It is a foil-backed, automotive-grade insulating material. Does it work? This material is often used to soundproof music recording studios! This will take the better part of a weekend to complete, but the reduction in road noise will have you smiling on your next long trip.

Things You'll Need

• Safety glasses
• Garage
• Wrench
• Screwdriver
• Vacuum cleaner
• Hose and water supply
• Insulation
• Masking tape
• Pen
• Tin snips
• Razor-blade knife
• Fiberglass rolling tool

Instructions

1. Park the vehicle on a level surface. Apply the parking brake. Open all of the vehicle's doors. Put on your safety glasses. Using a screwdriver, remove the door sill plates by removing the mounting screws.

2. Remove the seats. With a wrench, remove the mounting bolts of the front seat first. Once the bolts are removed, set the seats out on the garage floor. To remove the rear seat, push the seat bottom down and toward the trunk (toward the rear). When you feel it pop free of the mounting clips, lift it up and out of position. Set the seat outside of the vehicle on the garage floor.

3. Remove the seat belts and carpeting. Use a wrench to remove the mounting bolts and set the seat belts aside. Mark each belt with a piece of masking tape and a pen to ensure you put them back in the proper locations. Remove the carpeting by starting at the front of the vehicle and pulling it toward the rear. Remove the front carpeting first, then the rear. Most carpeting will be in two pieces. They are not glued down and will slide right out. Set them both aside and onto a clean floor.

4. Clean the floor of the car. Vacuum the floor to remove the dirt and sand that was under the carpeting and then wash it down. Allow it to dry completely before proceeding.

5. Install the sound deadening insulation. Peel the protective covering off of the back of the insulation to expose the adhesive and apply it to the vehicle's floor. Press the pieces down with your hands and smooth out any wrinkles and bubbles. You can trim the insulation to size or cut it to shape with a pair of large tin snips or heavy scissors. If you get any air bubbles, use a razor-blade knife to slit the bubble and push the air out by rolling the fiberglass installation tool over the area. Use the razor-blade knife to cut around all of the seat and seat belt mounting bolt holes in the floorboards. This material can be used to soundproof the doors as well. Remove the inner door panel by pulling them off with your fingers and placing the material inside of the door through the access holes. Installation methods are identical.

6. Reassemble the car. Reassemble in the reverse order. Use care to not tear the insulation's protective covering.

Tips & Warnings

• You may find it more convenient to make paper templates to trace onto the insulation before cutting it into shape.

• Save the small pieces from trimming to fill in areas where it is difficult to use a single large piece.

• Never use an open flame to heat the insulation pieces in an attempt to make it bend into shape easier, because fire or damage to the insulation may result.

References

• Car Audio Mag: Installing Dynamat