When it rains it pours. Doesn't it seem odd when we notice we need a new roof. Most roofs will be in need of replacement.
The exception being flat to minimal slope and metal roofs.

Commercial roofs can normally be re-coated with elastomeric coatings.

The existing roof even though oil base, a water based coating can be applied as long as you use a bonding agent,
giving the existing roof another 20 years of service to property owners.

Tar and gravel roofs will have to have a layer of foam insulation before applying coatings.
At least the coatings will give a longer life span of service before needing repaired.
On occasion tar and gravel will need  repaired compared to 20 years of life from  coatings.

The cost of a cool white roof is normally about half of the cost of replacing the existing roof.
Mid west roofing repair replaces many types roofs including shingles.

A roofing company applying these coatings can be found at Midwest Roofing Repair