Crews from Odsal and Bradford fire stations dealt with the blaze in three domestic garages at Chapel Fold in Wibsey, Bradford, just before 4am today Tues (June 19).
Odsal Fire Station watch manager Phil Warden said a number of what appeared to be new mattresses in one garage were destroyed in the blaze.
Building materials in another garage were badly damaged.
Watch manager Warden, said: "It is believed to be deliberate ignition."
Police also attended the scene.