Six fire engines have been sent to deal with a house fire in Ashdown Drive.
The fire is believed to have started in a first-floor bedroom of a terraced house and spread to the roof.
The fire service said the fire had spread to neighbouring rooves of the terraced house.
Crawley Fire and Rescue service were called out at 3.53pm and were still at the scene at 4.40pm.
Nobody was reported to be trapped or injured.
The A2004 Southgate Avenue has been closed at the Ashdown Drive junction with queueing traffic in both directions.
Traffic is also affecting Ashdown Drive between Colet Road and A2004 Southgate Avenue.
Chris Oxlade, who was on his way to a meeting at Thomas Bennett School, reported that the traffic on Ashdown Drive and Southgate Avenue was “chaos”.