Car Firewall Insulation

Upgrade Your Car Firewall Insulation with Sound Deadening and a Heat Shield

Upgrade Your Car Firewall Insulation with Sound Deadening and a Heat Shield

The automotive firewall is an important safety element in any vehicle. It seems like an obvious place for factory insulation, but in most cases, what you get is simply a sheet of metal separating the engine compartment from the passenger compartment. With little to no insulation, a fair amount of noise and heat travels to the interior of your car.

While most car enthusiasts focus on the floor and doors for sound deadening and heat insulation, the firewall is an often-overlooked area where some extra effort can make a big difference in your noise and temperature control.

The automotive firewall is an important safety element in any vehicle. It seems like an obvious place for factory insulation, but in most cases, what you get is simply a sheet of metal separating the engine compartment from the passenger compartment. With little to no insulation, a fair amount of noise and heat travels to the interior of your car.

While most car enthusiasts focus on the floor and doors for sound deadening and heat insulation, the firewall is an often-overlooked area where some extra effort can make a big difference in your noise and temperature control.

Why Install Car Firewall Insulation?

If you were to ride around with the windows up and your car stereo off, you’d likely hear some range of squeaks, knocks and rattles – and it’s safe to say that a fair amount of these are coming from the car engine and suspension. (And in hotrods or old classics, these noises can really be quite loud.) In the same way, you may notice your vehicle’s cabin feeling warmer than it should. Without an extra layer of material between you and the engine, there’s not much stopping that heat from making its way to the interior of the car. Keeping your car cool on hot summer days can be a challenge. Plus, excessive heat exposure can deteriorate your wiring over time (especially if you don’t have or have damaged OEM wiring insulation). Over time, the wires can stop working, short out, or even potentially start a fire in the worst-case scenario. (Yes, that was dramatic but it can happen. You can sit back down now.)

So adding an automotive heat shield and sound deadening material can truly be worth your while. It’ll bring a noticeable reduction in noise and heat. Your stereo equipment will sound better, and you’ll have greater control over your cabin temperature. Overall, it will make your ride much more enjoyable. Not to mention the fact that firewall insulation and soundproofing materials are pretty simple to install. (The coverable area of an average firewall is small – only 10-15 square feet!) And we make it really easy, with industry-best options to accomplish your firewall insulation goals.

car frame showing the exposed firewall

Upgrading Your Firewall Sound Deadening

Damplifier Pro™ is our most popular product. These sound deadening mats have a base of dense elastomeric butyl rubber with a thick annealed foil constraint layer, able to conform to and form a strong bond with sheet metal and rated to 450 F – perfect for a firewall. Installation is fairly simple: just cut to size with a sharp razor blade, peel to reveal the built-in adhesive, and stick.

Our Spectrum™ spray-on sound deadener has been a leading sound deadening solution for over a decade. This water-based, viscoelastic polymer is easy to apply, easy to clean up and engineered to perform. Essentially a sound deadening paint, it will adhere to most anything besides plastic and is perfect for those tough-to-reach parts of your vehicle (like the firewall!). Apply it in layers to choose your own thickness (we recommend 2mm, in two 1mm layers).

Installing a Firewall Heat Shield

For a best heat barrier, upgrade the heat shield with Mega Block™. Mega Block™ combines water resistant, lightweight and flexible melamine foam with a foil heat shield capable of reflecting 98% of radiant heat energy. By combining the two, you're able to get the best of both worlds with an excellent insulating layer under your aluminum reflective barrier. Application is easy with the peel & stick adhesive backing, and the performance is industry-best.

Thermal Block™ is our easy-to-use radiant heat barrier that can withstand up to 800° F. Composed of highly reflective foil and organic fibers, just face the highly reflective aluminum side toward the heat source to redirect 98% of radiant heat. It's commonly installed on top of Damplifier Pro™ to add a heat shield on top of the sound deadening layer. And it’s easy: Just peel and stick, being sure to leave at least 2” for airflow.

Another Insulation Strategy

Go with Luxury Liner Pro™ for cabin-side firewall soundproofing if you want to block out engine noise. A noise barrier is the only way to block out that turbo or diesel noise, so you’ll want to get as far up the firewall as you can (most people do not remove the dash). Luxury Liner Pro™ is a barium-infused mass loaded vinyl (MLV) that’s applied only on the cabin side. Applied on top of Damplifier Pro™ or Spectrum™, it’ll 2x your sound reduction by blocking out unwanted engine noises.

How to Install Firewall Insulation and a Firewall Heat Shield

The process is relatively simple: Clean, measure, cut, apply. The first layer will be your sound deadening material (either Damplifier Pro™ or Spectrum™), followed by a heat shield (Mega Block™ or Thermal Block™). The goal is to cover as much of the firewall as possible with your heat shield so that you can redirect radiant heat away from the metal. Cut around screws and nails where you need to, keeping gaps to a minimum.

Step-By-Step Guide

  • Once you’ve accessed the engine cabin, you’ll need to clean the firewall. Whether you give it a good pressure-wash or scrub it with denatured alcohol, starting with a clean surface gives the products the best chance to fully adhere to the firewall.
  • If you’ve opted for Spectrum™, spray away – covering every possible square inch of the firewall.
  • If you’ve decided to use Damplifier Pro™, it’s time to create the template. Use paper or cardboard to trace the parts of your firewall you want to cover. 60% coverage will be plenty to deaden the metal, but we recommend 100% for a firewall to enhance thermal insulation. If you decide to cover 100% of the metal, be sure to note where any screws or bolts will need to poke through the material and punch holes accordingly.
  • Place the template over the Dampifier Pro™ sheets and carefully cut the material to match. (We recommend a sharp razor blade instead of scissors.)
  • Now, before installing Damplifier Pro™, place it on your insulating material of choice (either Mega Block™ of Thermal Block™), and trim that to match. If you have a ragged edge, bind it with foil insulation tape or duct tape. We generally recommend using foil tape on all edges of your heat shield for high-heat applications.
  • Heat the backside of your firewall-shaped Damplifier Pro™ sheet to ensure optimum installation. Then, simply peel and stick the sheet straight onto the firewall. Use a roller to apply equal pressure and ensure you have no air bubbles. Air pockets significantly reduce damping performance.
  • Apply your pre-cut Mega Block™ or Thermal Block™ insulation material directly on top of the Damplifier Pro™ or Spectrum™.
  • Mission complete! Your firewall is sufficiently soundproofed and shielded.

Install Like a Pro

  • Wear gloves when handling Damplifier Pro. Strongly recommended!
  • Measure twice, cut once.
  • Always ensure 2” of clearance between the engine and any material you’re installing.
  • Use a roller to press butyl sheets on for proper bonding. No air bubbles!
  • Set rubber mats like Damplifier Pro™ out in the sun prior to cutting – the heat will make them more malleable.
  • For patterns too intricate for scissors or a razor blade, consider a drum sander. We’ve only tried this on the Thermal Block, but it worked really well.

If you’re looking for the quickest and easiest way to get maximum results, consider a Second Skin Car Firewall Kit. These options combine exactly what you need to get the job done, from soundproofing and thermal insulation materials to adhesives, utility knives and hand rollers.

 

Make SUre To Celebrate a Job Well Done!

The beauty of firewall soundproofing and insulation? Aside from protecting your vehicle from excessive heat exposure, it’s a project that offers immediate gratification. Your car will be noticeably quieter, allowing you to actually take a phone call while you’re driving (or hear yourself think). And your cabin’s temperature will be much easier to control, keeping you warm in the winter (but not hot!) and cool in the summer. Nice work, friends. Enjoy the ride.

Learn More with Our Ultimate Car Insulation Guide