Quiet and cool. That’s how you want your car’s interior to be. And we’re not talking about just a state of mind: we’re talking about keeping as much of the road noise and extreme temperatures out of your passenger compartment as possible. No one wants an interior that’s loud and hot.

If you’re contemplating any kind of interior makeover, whether it’s a simple carpet replacement, a show quality restoration, or a complete button tuft makeover, you need to think about what step to take regarding insulation. You and your passengers need protection from what’s happening outside. The solution is surprisingly simple – and it’s going to be right under your feet.

Thermal and acoustic protection

Sound deadener and insulation are nothing new on the automotive landscape. In fact, OEMs have been using combinations of latex-backed jute and aluminized felt pads and bituminous mats for years. You want more than just OEM replacement sound deadeners and insulation, though. 

Before you’ve finalized how you’re going to refit your new interior, take the time to consider which auto carpet underlayment solution you’re going to use to keep the noise and heat at bay. And while you’re doing it, consider why the OEM materials haven’t been terribly effective:

·   Heavy-woven jute pads not only rot over time, but are prone to holding moisture and odours.

·   Aluminium-backed felt pads are notorious for ripping, delaminating, and decomposing.

·   Asphalt-based bituminous mats become brittle and lose their adhesive and protective properties.

The lesson here is that aside from just dampening sound, reducing vibration, and blocking heat transfer, you want materials that don’t diminish comfort and can be expected to last. Fortunately, there are ranges of aftermarket liners and underlays that are capable of providing any kind of thermal or acoustic protection a car owner will ever need. Especially when they’re combined.

Stage 2 acoustic underlays

Multi-layered, stage 2 acoustic underlays are mass noise liners that absorb sound and heat. With their 6mm open cell and 6mm closed cell foam composition (12mm total thickness), they can be used either alone as an under carpet decoupling layer, or in conjunction with a stage 1 vibration dampening layer.

Weighing only 0.55kg/m², these underlays can be applied either horizontally or inverted using a peel and stick backing, and can be cut and moulded to perfectly fit any installation area, including:

·   Under carpets;

·   Inside quarter panels, body wells, and door cavities; and,

·   Against firewalls.

Acoustic underlays can be used anywhere an OEM jute or felt pad would have been used, with the advantage that they’re waterproof, won’t rot, and enhance the entire feeling of quality and comfort when applied under a carpet.

Stage 2 waterproof underlays

For convertibles, 4x4s, and other open-top vehicles, waterproof auto carpet underlayment is as fantastic at providing thermal and acoustic insulation as it is at repelling water.

Also weighing only 0.55kg/m² and with all the same adhesive and applicability characteristics of stage 2 acoustic underlays, waterproof underlays can be applied directly to the undersides of carpets and roof skins. This makes them a fully removable barrier that can still reduce radiant heat by up to 20°C.

Stage 2 mass noise liners

Constructed from a 2mm mass loaded vinyl layer affixed to a 10mm closed cell foam layer, mass noise liners are the exact type of sound abatement material used in premium luxury cars. Weighing 4.5kg/m², they’re true heavyweight underlays, and when cut to contour and simply dropped into position, are ideal for reducing all kinds of noise and heat originating from:

·   Exhaust systems;

·   Engine bays; and,

·   Cargo areas and floors.

They’re are also water resistant, don’t deteriorate, and are removable. Like all stage 2 underlays, can be combined with other vibration dampening materials as well.  

Plushlay® underlays

Plushlay® is an improved, polyester-based iteration of the classic jute underlay pads that retain the look of OEM insulation, but without the downside problems like rotting, or absorbing moisture or odours.

With a thickness of 16mm, these underlays offer the maximum in under-carpet comfort as well as noise and heat abatement, and can be cut and shaped to contour any floorpan. They can also be glued into place with adhesive spray or simply placed in position for easy removal.

In short, they’re a welcomed update to traditional OEM underlays that’ll work just as well in a new interior as they will in a Concours-quality restoration.

The conclusion

At the end of the day, there are a lot of options available that are designed to deaden all the unwanted noises and rattles, along with keeping the temperatures exactly where you want them. No special tools or expertise are required, either… and if you already have the interior removed, you’re well ahead of the game.

If you want climate-controlled solitude to listen to your own music, or just want to enjoy the sound of your own thoughts, there’s an aftermarket auto carpet underlayment for any purpose. With the added benefit that you can even combine underlays to create a thermal and acoustic barrier that’s specific to any type of vehicle.

Get the interior you want, and make it as clean or as custom as you can imagine, but don’t overlook the underlays that’ll help to keep it quiet and cool.