Replacement enters the conversation when the membrane has failed across an area rather than at one seam, or when water has reached the decking and insulation underneath. Sealing over compromised structure hides the problem without restoring it.
The assessment looks at the membrane, the deck and insulation below it, how the roof is reached, and what removal involves — vents, skylights, edge trim and any equipment mounted up top. Access and mounting details often shape the scope as much as the damage does.
