Fire was reported at 10 Maple avenue in Ambler Boro.  CH7 arrived on scene reporting a fire in the basement of a three story vacant factory building, with limited access to the building and seat of the fire.  E29 was called to cover station 7, Wissahickon Fire Co., but prior to responding, CH7 special called E29 to the scene to lay in.  E29 arrived, with E33 establishing a water supply, and prepared to supplement the existing supply.  CH7 requested the balance of the second alarm for manpower, with reports of fire in the void space of the first floor.  The crew from E29 went in service as a ladder company both on the exterior and interior, assisting to vent the building.  The fire was brought under control with numerous handlines and foam.  E29 was available after two and a half hours of service.