Quick answer: plan on 10–12 sq ft per door, and you rarely need 100% coverage
A butyl damping layer (CLD) works by stopping metal from ringing, so 25% coverage is the minimum for a noticeable change and 50–60% is the sweet spot for doors and floors. A typical pair of front doors uses about 20–24 sq ft. A full vehicle often lands between 36 and 60 sq ft of butyl, plus foam or MLV if you're blocking road noise.
Coverage calculator
Choose the areas you plan to treat. The calculator uses planning estimates for each area, applies your coverage level and adds trimming waste, then finds the lowest-cost kit combination.
Planning estimates by area
These figures are material at about 50–60% coverage, before waste. Larger vehicles and vans can run higher.
| Area | Compact or midsize car | Full-size car, SUV or truck | Priority for audio |
|---|---|---|---|
| Front doors (pair) | 20 sq ft | 24 sq ft | Highest: speakers mount here |
| Rear doors (pair) | 16 sq ft | 20 sq ft | High |
| Trunk or cargo floor and wheel wells | 10 sq ft | 16 sq ft | High with a subwoofer |
| Trunk lid or rear hatch | 5 sq ft | 9 sq ft | High with a subwoofer |
| Rear deck or rear quarter panels | 5 sq ft | 10 sq ft | Medium |
| Front floor | 10 sq ft | 14 sq ft | Road noise |
| Rear floor | 8 sq ft | 12 sq ft | Road noise |
| Roof | 10 sq ft | 16 sq ft | Rattles and rain noise |
How much coverage actually matters
| Coverage | What it does | Best for |
|---|---|---|
| 25–40% | Kills the loudest panel resonances | Rattles, budget door upgrades |
| 50–60% | Most of the benefit for the material used | Doors and floors on audio builds |
| About 100% | Maximum mass and damping | SPL builds, trunk lids and sheet-metal near big subs |
Butyl stops vibration; it is not a road-noise barrier by itself. For tire and exhaust drone, add a decoupling foam layer and mass-loaded vinyl (MLV) over the floor. A typical full-vehicle MLV layer is 25–40 sq ft.
Kits that match these numbers
| Kit | Coverage | Good for |
|---|---|---|
| Ballistic Hollow Point Door Kit | 12 sq ft | One pair of doors at targeted coverage |
| Ballistic Hollow Point Trunk Kit | 20 sq ft | Trunk floor, wheel wells and lid |
| Ballistic Hollow Point Bulk Kit | 36 sq ft | Doors plus trunk, or floors |
| Ballistic Tri-Layer | 12 sq ft | Doors and areas that need damping plus absorption |
| GP STFU v2 250 mil | 4 sq ft per sheet | Buy exactly the sheets you need |
| Ballistic Quilted Acoustic Padding | 15 sq ft | Absorption behind panels |
