- Q.What is the life expectancy
of hot-mopped asphalt on a flat roof? Will aluminum
paint extend the life of the roof? If so, how often
should the roof be recoated with the paint?
A.The average life
expectancy of a hot-mopped asphalt roof is 15
years. If the roof drains well, its life span might
be longer. The edge details are critical to the
life of this type of roof. Joints in any edge metal
must be maintained regularly, since the metal
expands and contracts at a different rate than the
roofing, which tends to crack the roofing at the
joints. An aluminum coating can extend the life of
the roof because it reflects more heat, reducing
alligatoring. The aluminum paint should be
reapplied every three to five years.