can roll roofing be used in cars

[MadelineFitz]

No, you should never use roll roofing on a car. It is a building material designed for low-slope residential or commercial roofs and is completely unsuitable for automotive applications. Using it on a vehicle is dangerous, ineffective, and will likely cause significant damage. The primary reasons are its lack of durability against road forces, extreme fire hazard, and poor adhesion, which can lead to it detaching at high speed.

Roll roofing is a heavy, mineral-surfaced material that lacks the flexibility and tensile strength needed for a car's exterior. The constant wind pressure, vibration, and changes in temperature and humidity on the road will cause it to crack, peel, or come off entirely. Furthermore, the asphalt-based material is highly flammable and a major safety risk, especially near a car's hot exhaust system.

For any automotive repair, you must use materials designed for the purpose. For a temporary patch on a roof or trunk, a high-quality, automotive-grade repair tape is the correct choice. For a permanent fix, the proper solution involves removing the damaged section, treating any rust, and having a professional weld in new metal or apply a fiberglass patch, followed by professional priming and painting.

Aspect	Roll Roofing (For Buildings)	Automotive-Grade Repair Tape
Material Composition	Asphalt-impregnated organic or fiberglass mat	Butyl rubber or advanced acrylic polymers
Weight	Heavy (approx. 75-90 lbs per 100 sq. ft. roll)	Very light and flexible
UV Resistance	Moderate, but not for constant movement	High, specifically engineered for outdoor exposure on vehicles
Temperature Tolerance	Low melting point; softens in direct sun	High heat resistance, often up to 200°F (93°C)
Adhesion	Requires specific roofing cements	Pressure-sensitive adhesive bonds strongly to auto paint/metal
Primary Risk	Detachment at high speed, creating a road hazard	If improperly applied, may leave residue but won't fly off

Attempting a cheap fix with the wrong material will cost you far more in the long run. A detached piece of roll roofing can cause an accident or lead to severe water damage and rust underneath, compromising your car's structural integrity. Always invest in the correct automotive products or seek professional help.

[VanAlyssa]

Absolutely not. I tried patching a rusty spot on my old truck's roof with a piece of roll roofing tar and some adhesive once. It looked terrible, flapped loudly the second I got on the highway, and started peeling off within a week. The sun made the tar smell awful. It was a complete waste of time and money. Just buy the proper black Gorilla Tape or a real automotive sealant from the auto parts store. It’s cheaper than causing more damage.

[PaisleyMarie]

Using construction roofing on a vehicle is a serious safety violation. The material is not designed for the dynamic stresses of driving. It can detach, becoming a dangerous projectile for other motorists. More critically, its composition is often flammable, posing a fire hazard near your car's exhaust. This is not a matter of a cheap repair; it's about adhering to basic safety standards. Such a repair would also be illegal in most states as an unsecured load.

[Adaline]

Think about it from a practical standpoint. A car's exterior needs to handle wind, rain, vibration, and huge temperature swings. Roll roofing is meant for a stationary, flat surface. It's too stiff, too heavy, and the adhesive isn't made for painted metal. It won't seal properly, so water will get trapped underneath and cause massive rust problems. You'll end up with a much bigger, more expensive repair bill than if you had just used the right tape or taken it to a body shop initially.

[Ortega]

I understand the temptation to use what's on hand for a quick fix, especially on an older car. However, the properties that make roll roofing good for a shed roof make it terrible for a car. It lacks the necessary flexibility and will crack. The surface isn't smooth, creating drag and noise. Most importantly, the adhesive will fail. For a safe, temporary seal on a roof seam or a small hole, use a dedicated automotive butyl tape or a vinyl repair patch. They are designed to stick and last on a moving vehicle.