How to Repair a Flat Roof?

[smith watson]

Flat roof leaks rarely are directly above where the leak is noticed from below. Water usually travels underneath the roof membrane until it finds a low point in the ceiling below.

If you can definitely see damage from above the roof then that's where you might want to apply tar/sealant. If you can't find damage then the roof might be leaking in several very small areas, in which case applying a waterproof/resistant membrane and covering with a thin layer of pea gravel (to hold it down) might be an option. Be sure there's a slope toward the drains.

Another option is to lay down pressure treated 2x4s/4x4s before laying down the membrane. This will create channels for the water to run toward the drain while creating a currogated profile to help air circulate underneath...to dry out what is