Door and glazing frames include intumescent material positioned in a dado that is formed in a jamb side surface. Trim materials are positioned over the intumescent material to improve the appearance of the frame and to prevent tampering with and damage to the intumescent material. The jamb trim is preferably made of a cut hardwood panel having a thickness that allows heat to be transmitted to the intumescent material in the event of a fire so that the intumescent material will expand and fill a clearance space between the frame and the door or glazing. The expanded intumescent material inhibits the transmission of smoke and heat between the door and door frame. After expanding, the intumescent material will char and solidify, which may provide an added benefit of structural support for the door and or glazing.