Interior Sound Proofing
by Jeremy Goodspeed
A quiet solid ride is what every driver wants. It's the same whether driving your restored classic, or your late model SUV. Older vehicles have very little if not any sound proofing material to drown out road noise and vibration. Late model vehicles use an ample amount within the floorboard; yet use none on the outer door skins. Within the last 10 years, many advances have made sound proofing easier and more successful for the home enthusiast.
To begin the sound proofing of your vehicle, determine what areas of the vehicle will receive the treatment. Measure the approximate area that will be covered to determine how much material will be necessary to complete the job. This will be a rough estimate and will not take in consideration for force bars and other internal obstructions.
This process does require some disassembly, therefore door panel removal tools, and some knowledge of your particular vehicle is helpful. Be careful not to damage any parts as they are being removed. Any clips, screws and hardware should be placed in a Ziploc bag and labeled for proper reinstallation. It is best to work on only one panel at a time to reduce the number of parts removed at any one time and eliminate the confusion of hardware.
Once a door panel is removed, the plastic vapor barrier will need to be carefully detached as not to damage it. This vapor barrier keeps water from migrating into the vehicle and prevents water and moisture from damaging the door panel. There are two ways that a vapor barrier is attached: A vapor barrier that is attached with a spray adhesive will pull off by lifting evenly. Remove from the vehicle and place flat so that the adhesive will not stick together. A vapor barrier that is attached with a black bead like adhesive will be best to be removed by carefully slicing the bead with a razor blade while lifting up on the plastic. Be careful as not to cut the plastic. Some of the black material will remain on the vapor barrier, and the rest will remain on the door structure. This is normal, and will help to align the barrier upon reinstallation.
Now that the plastic is removed, it is time to determine how the sound proofing material will be applied within the panel. Generally, it is a good idea to take a couple of basic measurements and cut the pieces to allow for the most complete coverage using the least amount to waste. It is not necessary to completely cover the metal panel, however the more complete the coverage, the better the sound absorption. To cut the material, use a metal straight edge and a quality utility knife. A sharp blade will cut best. Just score the foil side of the material and fold. The material will break clean. Test fit the pieces while the plastic backing is still attached. Trim as necessary to make a perfect fit.
Before applying the material, it is a good idea to image the pieces for the other side. Most vehicles are exactly the same from the left side to the right. Imaging the pieces will save time and also allow for an even amount of material used. Place the pieces foil side together and use the metal straight edge to score the material. Once the pieces are cut, set aside until needed.
To apply the material, remove the plastic cover from the back of the sound proofing material exposing its adhesive. Place the material in the proper location and attach. The use of a heat gun or a hair dryer will allow the material to soften and make for a more complete bond with the metal panel. For areas that are contoured or have uneven pockets, a heat gun will allow the material to completely form to the contour.
Once the material has been completely applied, reinstall the vapor barrier and the panel as necessary. Be sure to properly reattach all door release cables and replace any broken door panel clips to eliminate any unwanted rattles.
Repeat this process on each panel until desired noise reduction is achieved.
Once finished, just one closing of the door will immediately demonstrate the difference in tone. It will make a Toyota pick-up sound as solid as a Mercedes-Benz door being closed. Better yet, just take you vehicle for a drive. You'll notice the difference.