The blaze in Downpatrick is believed to have been accidental.
It comes as the Northern Ireland Fire & Rescue Service revealed crews are still dealing with the impact of gorse fires.
A spokesperson said: “Firefighters have continued to respond to other incidents across Northern Ireland and attended a well-developed house fire in Downpatrick.
“Our regional controls staff provided fire survival guidance to persons trapped in the first floor of the property.
“A fire had started in the garage filling the property with smoke.
“Crews from Downpatrick, Comber and Ballynahinch arrived on scene and extinguished the fire.
“A member of the public acted quickly and managed to get two persons out of the property with a ladder.
“The fire is believed to be accidental.”
Fire service resources have been stretched due to blazes in the countryside in recent weeks.
Hot, dry weather has seen gorse fires spread across Northern Ireland.
A blaze near Clogher in Co Tyrone is continuing to burn.
NIFRS added: “Two appliances remain at Ballagh Road in Clogher following the extensive wildfires in the area. The temperature reduced overnight which has helped the situation. Crews will continue to review the area over the next few days.
“We are asking the public to remain vigilant to fires in the countryside, as the dry weather continues.
“If they see fire please dial 999 to ensure NIFRS are aware of the fire.”
Officials said the Clogher wildfire has damaged about a third of Slieve Beagh.
Agriculture Minister Andrew Muir said: “The current fire near Clogher is another stark reminder on how quickly they can spread, creating significant risk to life and property while causing extensive environmental damage.
“The fire in counties Tyrone and Monaghan has torn through approximately a third of a precious protected site which includes a Special Area of Conservation for the endangered Hen Harrier during nesting season as well as important blanket bog habitat.
“With the current conditions set to last into the weekend and beyond I plead with everyone to heed the elevated hazard warning issued, remain extra vigilant to fires in our countryside and report to the police or Crimestoppers anyone you know involved in deliberate and malicious fires.”
This article was amended at 4pm on May 10 to state two people had been rescued after further clarification from NIFRS.