A fire on the roof of the Pacific Beach Hotel in Waikiki on Friday caused an estimated $75,000 in damage, a Fire Department spokesman said.

The fire was reported at 2:47 p.m., brought under control at 3:09 p.m. and extinguished less than 25 minutes later, Fire Capt. Terry Seelig said.

Most of what was burned was construction materials that were going to be used to build a foundation for an air handler on the roof, Seelig said. Damage was confined to the roof.

The building materials were made mostly of fiberglass, which when burned produced heavy black smoke, some of which entered the penthouse. A fire investigator was trying to determine what caused the fire.

Pacific Beach officials evacuated both of the hotel’s towers at 2490 Kalakaua Ave. No one was injured.