Top 2 Automotive Sound Deadening Materials (and how to install them)

Driving a car can be really pleasant if you’re able to stop road and engine noise from entering the cabin.

By soundproofing your car, you can also improve the quality of sound coming from the stereo, as well as conversations you can have while driving.

To get these benefits, it’s important to get the right material for the job.

The good thing about automotive sound deadening materials is that they’re pretty affordable. That’s true even for the top options on the market.

Also, the area in the car that has to be covered is relatively small, when compared to other soundproofing projects.

The main features to check out when buying automotive soundproofing products are:

sound deadening qualities
practicality
installation difficulty
durability of the material
personal experience or experience of other users

With those aspects in mind, here are the best automotive sound deadening materials at the moment.

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FatMat Self-Adhesive RattleTrap Sound Deadener

I didn’t use this mat myself, but a friend of mine got it in his Ford F-150.

If you’ve ever driven in one of these pickup trucks, you’re well aware that their engine produces a lot of noise, especially if it’s a manual and you’re switching gears. The noise coming from the floor is not as bad, but it’s also bad enough to do something about it.

I noticed the difference from RattleTrap Sound Deadener immediately after he applied it to the engine compartment, the floor and the doors.

And here are some specs that make this option a great choice.

First of all, it’s pretty versatile and easy to install. It can be applied to almost any area of the car, including the floor, roof and the doors of the cabin, as well as the engine compartment and the trunk.

It’s self-adhesive, which means that it sticks anywhere you place it. But that’s not true every time. Many soundproofing products claim that they’re self-adheisve, and then you still have to use an extra adhesive to make sure they stick properly.

My suggestion is using 3M General Trim Adhesive if you find it to be necessary. First you spray the area, and then you place the mat over it. Then it will definitely stick.

The engine compartment can be tricky with other mats that don’t withstand heat very well. Some people have used cheap auto mats and they actually melted. They noticed it only when the car started to reek pretty bad and the noise returned.

That’s not the case with FatMat (link to Amazon), as you can see from hundreds of customer reviews on Amazon that address this usually problematic feature. It’s a heat-resistant mat and it’s quite durable at that.

Of course, all of this would be negligible if the mat didn’t provide quality soundproofing.

But take a look at this comparison:

The Dynamat material that is widely used in cars for soundproofing is 67 mil thick, and many people consider it one of the best sound deadening mats for cars.

However, FatMat is 80 mil (!) thick. Other than the type of material that the mat is made from, this sort of thickness is the most important factor when it comes to reducing vibrational noise.

When you look at the price per sq ft, you will also notice that FatMat is superior to Dynamat. Dynamat is a little over $4 per square foot, whereas FatMat is a little over $2 per square foot.

But don’t get me wrong; Dynamat is popular because it works pretty well. But it’s also more expensive due to its popularity, not because it has any special qualities.

So this FatMat is actually more affordable than Dynamat and you get even better sound absorption from it.

This is a pretty cool video that shows the FatMat in action:

If you get the 50 sq ft option, that should be enough to cover most of the critical areas in your car in one go.

Car Spray-On Sound-Deadening Foam

That’s right, spray-on soundproofing foam is a real thing. It’s like shaving cream, but instead of applying it to your beard, you spray the thing all over the area you want to soundproof. There are 7 main advantages and 3 disadvantages to using spray-on foam.

PROS

It’s easier to soundproof hard-to-reach places. Spray-on foam is convenient for inside door panels, trunk interiors, fender wells…etc.
You can spray multiple layers of foam over the same area, and increase density and the sound deadening effect by doing so.
The foam can withstand high temperatures, up to 300 degrees Fahrenheit, making it a solid option for the engine compartment as well.
Reduces vibrational noise pretty well.
It can be sprayed over rusted areas.
It takes about 20 minutes for the foam to dry.
It’s the most affordable solution for reducing noise in the car.

CONS

It can look messy.
Not as effective for large areas as the sound deadening mat
It’s not a full long-term solution. If the foam is exposed to high heat on a regular basis, it usually dissipates in a few years.

Overall, it’s a great solution for hard-to-reach-places and those places where you don’t care how it looks. I don’t recommend using it in the visible parts of the car cabin though, because a car mat would definitely looks better. But you can use it for doors, because the foam would be covered by the door panel anyway.

Boom Mat Spray-On (check out the price on Amazon) is widely used for cars. One can has enough foam to cover 20 sq. ft., so it’s a pretty sound(proof) investment.