For flat or low-slope buildings, a Tar and gravel roof is a popular and affordable roofing choice. This kind of roof is made up of several tar or asphalt layers, roofing felt for reinforcement, and gravel on top. The layers underneath are shielded from UV radiation, weather damage, and normal wear by the gravel. Known for their extended lifespan, tar and gravel roofs usually last 20 to 30 years when properly maintained. They are energy-efficient for residential and commercial buildings because they provide superior insulation and waterproofing.