Sound Deadening Spray vs. Mat Insulation for Vehicles


Does it get noisy in your car cabin when you’re driving? I had this problem in the past with my own car, but found a simple solution. The most common noises come from the road, wind, rain and other cars passing by. But you probably already saw that there are both mats and sprays that can be used for sound insulation. So the question is whether they work equally well? Here’s the quick answer:

Overall, mats are a better option. But a sound deadening spray can be used for some areas as well. Mats are better for covering larger areas such as the floors, because they look nicer and are more durable. They’re also thicker. You’d have to apply a lot of layers with a spray to reach the same thickness, which can make it expensive. But in some vehicles there are hard to reach places in the engine compartment, doors and other areas where a spray can come in handy. So the takeaway is this: use mats for larger areas in the vehicle and use sprays for smaller, hard-to-reach places when necessary. 

In this article I’ll show you the best sound deadening mats and sprays. I’ll also show you the key areas where you can apply these materials to get the best insulation possible.

These are the best sound deadening mats in 2018.

  • Dynamat Xtreme (click to check current price on Amazon) – Dynamat is a brand name in the sound deadening industry. It’s one of the thickest mats on the market and provides especially powerful protection against road noise (impact noise). If you want proven quality this is the go-to product.
  • Noico Automotive Sound Deadener (click to check current price on Amazon) – Noico has become a very popular sound deadener over the last 5 years. There are logical reasons for that. It’s thicker than Dynamat, AND it’s almost half the price. Go figure! The same materials are found in both products. Due to the aluminium foil, it’s heat resistant and can be used to insulate all parts of the vehicle, including the engine compartment.
  • FatMat Rattle Trap Sound Deadener (click to check current price on Amazon) – FatMat is almost identical to Noico. It consists of the same combination of thick and flexible vinyl plus aluminum foil. The 80 mil thickness is identical. The difference is really found in the price as FatMat is slightly more expensive. However, the main reason is that FatMat package also includes a solid installation kit. The installation kit includes a roller, knife, and a few other less important products. The roller is helpful when installing any of these mats because it makes it easier to apply pressure and get them to stick properly on the surface. And a knife is necessary, even though you can use any sharp knife in order to cut the material to the required size. Overall, I’ve had great experience with FatMat and my friend used it in his pick-up truck and it made a noticeable difference. 
  • Mass Loaded Vinyl (click to check current price on Amazon) – MLV was originally designed for insulating vehicles but people mostly use it nowadays for home soundproofing projects. However, ALL of the before-mentioned mats have vinyl as the main material. One difference is that they’re self-adhesive and the original MLV is not. So you have to use a general spray adhesive to make it stick. It’s really no biggie, and this is a really effective product against impact noise. Which is why I recommend using it on the wheel wells because it’s 1/8 inch thick and is flexible enough to absorb the impact from tires hitting against bumps and crevices on the road better than other products. It can also be used to soundproof regular walls, doors and fences by installing it directly on the surface or in case of walls, directly on the studs.
  • Vibro Closed-Cell Foam Insulator (click to check current price on Amazon) – This mat is typically used in combination with one of the before-mentioned sound deadening mats. So once you’ve covered the surface with one of them, you can also apply this closed-cell foam mat on top of it. There are multiple reasons why this is a great option. It adds 1/4 inch thickness on top of the sound deadener, which improves insulation and can increase the durability of the sound deadener. It also makes it look nicer, because it will come on top of the aluminium surface. It’s waterproof and fire retardant so it can be applied to any part of the vehicle. It can also be used on top of a surface that was treated with a spray-on product. However in that case make sure that the surface is evenly sprayed, because bumps will make it harder to stick.

There are a few other product such as Second Skin Damplifier Pro. But from what I could gather, these are the top options for full application.

…and these are the areas where it’s better to use a sound deadening mat:

Cabin floor

It’s important to add thickness to the cabin floor in order to block the road noise coming from tires. Some people will remove the car seats in order to cover the entire floor. This can be a lot of work but it’s worth it. But if you don’t feel like doing that, simply cover the parts of the floor you’re able to reach. This will still be a substantial amount of the floor and you’ll get solid results.

Doors

If you want to reduce wind and traffic noise you need to soundproof the doors. This process requires unscrewing the door panel to reveal the hollow part of the door. Next step involves placing the sound deadening material inside the door. Once you’ve done that, screw the door panel back and you’re done. I’ve covered door soundproofing in more detail in this article with helpful video tutorials.

One other area of the door that might require additional insulation is the gasket. That’s the rubber seal which is supposed to cover the gaps around the door when it’s closed. After a period of time this rubber seal can get cracked or not hold as well as it used to. If it’s only slightly cracked you can try patching it with some tape or a strong adhesive. But if it looks really worn down, replace it with a new and thicker one if it’s available. Many people have found this thick universal rubber seal (link to Amazon) to be a great replacement product.

Roof/Ceiling

Traffic, wind and rain noise can all be minimized by covering the roof with a good mat.

You’ll want to remove the cover fabric (headliner) first. There’s no universal tutorial for doing this because each car is different. But this video shows the general process.

Once you’ve removed the headliner, stick the mat on the ceiling. Then place the headliner fabric back in place. The sound deadeners aren’t really thick so there shouldn’t be any problems with doing this.

Trunk

Whether you should insulate the trunk depends a lot on its size. A large and empty trunk can act like a large diaphragm which vibrates and makes the road noise seem even louder. In that case, insulating it with mats can be really helpful. This is really straightforward. First remove the fabric (if there is any) and cover the entire trunk with the mat of your choice. Then place the fabric back on. Done.

Engine compartment

Some engines are louder than others. But all engines can be heard by the driver, the other passengers and others who happen to be close by. Unless of course, you cover the engine compartment with sound deadening material.

All of these products were designed to resist heat and be used for soundproofing engines. Simply cover the inside of the hood with a mat and other smaller surfaces of the car’s body either with a mat or a spray-on product. Furthermore, you can apply an additional layer or use the Vibro closed-cell foam mat to add extra thickness and insulation.

Wheel Wells

Covering the wheel wells can help reduce noise coming from tires. But it’s not exactly a DIY project that everyone can do. It requires removing the wheel in order to have enough space to apply the material on the surrounding surface. This video shows the application of the material. For most people, I suggest going to a professional mechanic and having them do it for you:

This is definitely helpful in reducing road noise. But covering the floor and the doors with a thick mat is usually enough to reduce road noise to a point when it’s no longer bothersome. I recommend doing that first. If the noise is still too loud for your taste, then I would do the wheel wells as well.

These are the best sound deadening sprays:

Foam It Green 602 Spray (click to check current price on Amazon) – I can confidently say that this is the best insulation spray on the market. It’s a closed-cell foam spray that can be used to insulate virtually any area in your home or vehicle. Some users have insulated their entire mobile homes using only this spray. It’s a class 1 fire retardant, which means that you can use it safely anywhere, including the engine compartment. The package also includes 17 accessories including nozzles, spray fan tips, a tyvek suit, goggles, & gloves, which are recommended, especially when applying in closed areas.  However, the major downside is the price. I would recommend using it only for big soundproofing projects or for soundproofing a large vehicle like a mobile home or an RV. 

3M Undercoating Spray (click to check current price on Amazon) – This spray is a lot more affordable but it doesn’t provide the same sound deadening qualities. It’s primarily used for protecting metal surfaces against corrosion, build up and abrasion. However, it provides a thick coating which can also act as a sound deadener. This is the type of spray you should use for those small gaps between sound deadening mats and smaller parts where it’s too difficult to install a mat.

Sprays to avoid:

I’ve researched a few more sprays such as LizardSkin and Boom-Mat spray. My friend used the Boom-mat spray on his pick up truck doors. It had a pretty strong industrial smell which took about a week to wear off completely. And unfortunately the foam also wore off after a few months and had to be re-applied again.

I haven’t had experience with LizardSkin but the stats and user reviews are not too reassuring. You need to apply many layers to get the same effect you’d get from a regular sound deadening mat. And just like the Boom-mat spray, it wears off after a few months and doesn’t tolerate heat very well.

Sprayed foam can look ugly, so it’s best to use it on less visible surfaces. Case in point:

Final Word: Sound Deadening Spray vs. Mat

Allow me to recap the pros and cons of both options:

Mats are the best option for all large surfaces and surfaces where it can be easily installed. They’re more affordable, since you’d have to use a lot more spray to get the same thickness and sound deadening. They also look better and they’re more durable. Almost all of them are self-adhesive and can easily be cut to size with a knife.

Sprays are the best option for small nooks and crevices where placing a mat is difficult. They’re also useful for sealing gaps between mats if they’re present. These can sometimes be left if there’s a weird angle for example when covering wheel wells or on the corners. They can also be useful for doors, especially around handles and other small objects you might have to work around. Unless you plan on using the super powerful Foam it Green Spray that I mentioned earlier, I would get a spray only for these small areas and as a back-up.

So I hope that answers your question! Having peace and quiet when driving can be a game changer. Applying these materials can improve the acoustics in the cabin, and make driving a meditative experience instead of a headache.

Luka Baron

Soundproof expert and a staunch opponent of noise. This website is a free source of information on how to 'keep it down a notch'. I update the content regularly to keep up with advancements in the soundproofing industry.

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