A building constructed before the effective date of the first Flood Insurance Rate Map (FIRM) for a community. Pre-FIRM buildings were built before current floodplain management regulations and often do not meet modern elevation requirements. These structures typically qualify for subsidized flood insurance rates under the National Flood Insurance Program, though these subsidies are being phased out. Pre-FIRM buildings can maintain grandfathered rates if they met the floodplain management requirements in effect at the time of construction. When Pre-FIRM buildings undergo substantial improvement or substantial damage, they must be brought into compliance with current standards.