A fiber insulation application nozzle having a small opening for introducing insulation into cavities through a small opening is provided. The diameter of the body portion of the nozzle corresponds with the diameter of the conventional deliver hose from an insulation blowing machine. The nozzle includes a reducing section tapering to an exit portion having a diameter one-third of the main body. A gas injector tube is introduced along the inside surface of the exit portion of the nozzle and is directed along the surface. Fiber insulation in the nozzle is compressed prior to entering the exit portion. The gas injected into the exit portion aids in moving the particles through the nozzle. The compressed fibers are surrounded by high pressure gas and are caused to expand into a fluffed condition upon leaving the nozzle. An impinging stream of liquid adhesive is provided within the exit portion of the nozzle so as to thoroughly wet and coat the insulation fibers within the nozzle as they exit the nozzle. As the fibers expand and fill the cavity in the fluffed condition the adhesive sets forming a rigid mass of insulation. Wedge shaped ramps can be provided within the nozzle so as to produce a turbulent flow within the nozzle. Adhesive spray nozzles can be mounted on the exterior side of the nozzle so that the applying surface will be wetted prior to the depositing of the wetted fibers.