What was found
CLIMBING THROUGH 11,000 MSL, HEARD A LOUD PRESSURIZATION BUMP. CABIN RATE CLIMBING AT 2000 FPM AND CABIN ALT CLIMBING. LEVELED AT APPROX 14000 MSL AND STARTED DESCENT TO 10,000 AT APPROX 11000 MSL CABIN, ALT 1 EICAS. COMPLIED WITH QRH, SELECTED AUTO 2 AND MANUAL, NO RELIEF. RETURNED TO DEPARTURE. R & R ALL DAMAGE FROM BS 1699.0 TO 1787.45 & S25R TO S25L, DONE BY TAIL STRIKE. ACFT STRUCTURE DAMAGE INCURRED DURING CLIMB-OUT.