American Standard unit, manufacture date of '99, was freezing up, cleaned the exterior unit of build up & debris. Now there is Ice build up on indoor coil. Water on basement floor. The A/C is constantly running trying to cool the air, which it does over time. Just tonight it was 76 in the house & 4 hours later it had cooled to 74 and had been running all day. Daytime the thermostat is set to 75 and in the evening 72 degrees. All windows & doors closed. Any suggestions or is a service call required? Could the freon be escaping or low?

Check for a dirty filter or blocked return air.
Shut down unit and leave indoor fan blow.
After a few hours turn back on.
If it ices up again you will need to call for professional on site service.