The aircraft was on a flight from Riga Airport (EVRA), Latvia, to Dublin Airport (EIDW), Ireland. The flight was uneventful until the aircraft began its final approach into Dublin, at which point the Flight Crew received a warning of a spoiler fault. They carried out the appropriate checklist, which included an increase of 8 kts to the final approach speed. However, at this speed, and with landing flap selected, the Commander, who was Pilot Flying (PF), experienced difficulties controlling the aircraft in roll. The Commander further increased the approach airspeed, which improved controllability, and the aircraft landed normally. There were no injuries.