Hot mop or hot asphalt roofing is an effective way of covering a flat or low-slope roof, in which asphalt forms the waterproofing component of the roof membrane. Asphalt lugs are melted and then mopped under and over a layer of tar paper, resulting in a an impermeable, multi-layered roof covering that will last up to 20-25 years if the roof has good drainage that avoids puddling.

An affordable roofing solution, it can be installed relatively quickly. However, it can be quite a messy and potentially hazardous job that really should be tackled by trained professionals.