Butyl vs. Asphalt Sound Deadeners: Settling the Age-Old Debate

If you’ve been searching for automotive sound deadening mats, you may have caught on to the whole base material debate. When I first started learning about this, I found it pretty confusing. So today we’re going to go over the butyl vs. asphalt sound deadening debate and reach a conclusive answer once and for all.

Those of you who’ve been following my articles for a while know that I’ve actually said something on this subject before. Still, for those who haven’t had the chance to familiarize themselves with sound deadening mats, I’ll give a brief overview of what these products do and how you can install them.

After the general overview, we can dive right into the butyl vs. asphalt comparison. Can you guess which of the most famous automotive sound deadening materials are butyl and asphalt-based? Let’s find out!

Butyl based sound deadening materials vs asphalt based materials.

Intro to Automotive Sound Deadening Materials

Before I get into the matter at hand, I thought that I should give a brief intro to sound deadening materials. There are four major types of automotive sound deadening materials on the market:

  • Sound deadening sprays thicken the metal frame of a car.
  • Insulation pads go under the carpets.
  • Foam materials for the interior of the cabin.
  • And sound damping mats, which we’ll be talking about today.

Sound deadening mats usually have foil on one side and a sticky black material on the other. Their effectiveness usually depends on their thickness and their base material. Additionally, the base material of these mats also determines how they’ll behave in extreme temperatures. But before we really get into all of that, let’s talk about how sound deadening mats can be installed.

Application Process

The installation of sound deadening mats is almost always a process you’ll want to set some time aside for. Depending on the thickness and the overall maneuverability of a certain product, you may have to set aside anything between a couple of hours and a whole day. And that’s without even taking the size of the surface you’re covering into account.

Typically, you’d start by getting to the metal you want to cover. If you’re working on doors, that’ll mean taking out the speakers and removing the inner layer. For the ceiling, you’d need to take out the headliner. And, if you wanted to go all out, you could even remove the car seats.

Once you remove everything you wanted to, you can get the mats ready and get your protective gear on. After all, both butyl and asphalt are tacky — they are there to attach the mat to the metal. So wearing clothes and gloves you don’t mind getting dirty is preferable.

As I’ve previously mentioned, some sound deadening materials may be easier to handle than others. At this point, you’d cut the mats into more manageable pieces with a utility knife or perhaps even sturdier tools. Again, you can expect varying levels of messiness here.

After you have separate pieces, you’ll paste them onto the inside of the outermost metal layers of the doors and buff them in. So through the openings in the door frame — you’ll know them when you see them. The roof, the hood, and the trunk will be much easier to work with, though.

The process of covering the entire interior of a vehicle with sound deadening mats is, as I’ve said, pretty strenuous. What results can you expect to get after putting in that kind of effort?

How Do Sound Deadening Mats Work?

Again, since I’ve already talked about the soundproofing effects of automotive mats, I’ll keep it brief. If you install sound deadening mats on at least 25% of the surfaces you’re working on, you should be able to hear the difference in both the amount of outside noise that’s getting through and the various noises your vehicle itself is making.

Ideally, though, you’d need to cover as much of the metal as possible for the best results. Of course, some products are going to be more effective than others no matter what features they have. Whether that’s really because of their base material and their thickness or simply shoddy manufacturing, I cannot say. However, the base material has proven to be one of the crucial factors on a practical level.

So what are these mats actually doing to the metal that’s making the inside of your car quieter? Essentially, the mats work by gripping the metal and making it thicker and sturdier. They also give it the tiniest bit of padding. Still, it’s enough to lessen the noise you hear from the various loose parts that would otherwise keep clicking against the metal.

Also, because of the way the mats are adhering to the sheet metal, the metal isn’t able to vibrate as much as it usually does during a drive. When you put the mats in, the first thing you’ll notice is that slight rattling noise. That was actually caused by the exterior sheet metal in your doors, if you’ll believe it. In fact, if I had to tell you to put sound deadening mats in only one area, I’d recommend working on the doors first.

Butyl vs. Asphalt Sound Deadening Materials

Butyl-Based Materials

Finally, we’ve arrived at the destination of this little trip. Now that we know everything we need to know about sound deadening mats: what is it that makes some more effective than others? As I’ve said before, it all comes down to the base material and the thickness of the product. However, sometimes the base material is the determining factor, as in the case of 80 mil Noico vs. 67 mil Dynamat.

In my review and comparison of these two products, which are arguably the most popular mats on the market, I had concluded that the thicker 80 mil material was indeed inferior to the slightly slimmer Dynamat. What’s more, the general user consensus seems to agree with my assessment, so there must be something there.

Dynapad vs Dynaliner vs Dynamat.

Still, that particular review was a bit tricky, but it was also fairly revealing. While both Noico and Dynamat are, indeed, butyl products, Noico happens to have an asphalt undercoat. Could its performance be suffering because of it? Well, you should keep in mind that it’s still one of the best sound deadening mats on the market.

Still, it’s completely possible that the addition of asphalt caused a decrease in efficiency as well as the slight rubbery scent of the product. There are other products that illustrate the disadvantages of using asphalt sound deadening mats, though. So let’s see how efficient asphalt-based materials would be.

Asphalt-Based Materials

Since I’ve already compared a couple of butyl products to an asphalt mat, I might as well use the same example here. As one of the most popular asphalt-based sound deadening mats out there, Fatmat has pretty positive reviews across the board. However, in my opinion, most of the positive reviews are to do with its exceedingly affordable cost, rather than with excellent performance.

Even customers who are happy with the price can’t ignore the abysmal thickness of the product, which is only 50 mils. Also, similarly to other asphalt products, Fatmat emits a peculiar rubbery scent. In fact, that flaw has been noted in Noico mats as well, although to a much smaller degree. As I’ve said, Noico products are technically butyl-based, even though they have that asphalt undercoat.

One possible cause of this scent may be the relatively low melting point of asphalt. Even outside of automotive soundproofing purposes, asphalt doesn’t handle heat well. Asphalt roads also soften up in hot temperatures and get brittle in cold weather.

Naturally, that kind of material isn’t exactly ideal for vehicles that tend to overheat or for people who live in moderately to extremely hot climates. However, it might work if you don’t need to worry about those things. If your car doesn’t have issues with heat regulation and if your environment is usually cool throughout the year, you could install asphalt-based materials. As long as you’re willing to deal with the smell, that is.

The other example of an asphalt-based sound deadening mat I’ve found only further cements my bad opinion. The MFM Peel & Seal mat is not only asphalt-based but also very thin, at only 45 mils. So you see, when it comes to butyl and asphalt products, there’s no comparison.

Best Automotive
Sound-Deadening Materials

Butyl vs. Asphalt Sound Deadening: The Final Tally

Ultimately, if you’re choosing between butyl and asphalt sound deadening mats, you’re going to find yourself gravitating toward butyl. For one, there are more of them than there are asphalt materials — exactly because the manufacturers have started to move away from asphalt.

Taking into account all of the drawbacks of using asphalt mats, who wouldn’t? After all, butyl is way better at handling high temperatures than asphalt. And, besides, plenty of other soundproofing and automotive parts are made of butyl rubber. That has to count for something, right?

Well, while I certainly prefer butyl to asphalt, if only because butyl doesn’t have an odor and for its increased heat-resistance, the situation isn’t as cut-and-dried as that. What about the sound deadening mats that have both asphalt and butyl components, like Noico?

Like all things humans have created, butyl sound deadening materials must have their fair share of flaws. But, going by what we know now, they’re not very prominent ones. So it seems as though butyl products would win in a face-to-face with asphalt mats.

Even though products with at least a bit of asphalt in them tend to be more affordable, I wouldn’t recommend purchasing a product just because it’s cheap. Remember, butyl-based Dynamat is rather costly — but it’s also one of the most effective automotive sound deadening mats as well. Whatever you end up choosing, as long as you know how each of these materials behaves, you should be just fine.


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