Wooden doors come in 3 different types. Solid wood, hollow core and solid core. Each type of door is constructed differently. The solid wood doors are made from either frame-and-panel construction that uses natural wood or from a solid wood slab.This type of door is 100% made with natural wood. Hollow core doors are constructed with hollow cores which are cost effective alternatives for solid wooden doors. The solid core door has a mixture of wood particles glued together with heat, resins and hydraulic pressure. Hollow core doors are lighter than solid core doors and are easier to handle and install. Solid core doors provide more security than hollow core doors.