While exterior doors need to be tough enough to withstand the elements, interior doors are designed with privacy in mind. Interior doors tend to be lighter than entry doors, and come in a wider variety of styles.Types of Interior DoorsMost interior doors are hollow. Hollow core wood doors have a veneer applied over a wooden framework. Hollow core doors provide privacy, but offer little in the way of a sound barrier.Solid core wood doors are similar to hollow core doors, but the hollow area within the door is filled with wood fiber. Solid core interior doors offer the sound-deadening properties of solid interior doors at a lower price.Solid interior doors are heavy, act as sound barriers and come in many different choices of wood, including cherry, mahogany and pine. Solid interior doors are expensive and tend to expand or contract with humidity levels.Other types of interior doors include:Bifold doors that open by folding lengthwiseBypass doors that slide past each otherFrench doors with full length glassLouver doors with wooden slats for privacy and ventilationPocket doors that slide into a wall cavity.Bypass doors and bifold doors are often used as closet doors. French doors act as room dividers while keeping an area open and allowing the free movement of light.Louver doors are used for drying rooms and other areas where proper air ventilation is important, such as doors leading to hot water heaters.Prehung Interior Doors or Slab Doors?Interior doors can be purchased as slab doors or as prehung interior doors. Slab doors are simply the door itself, while prehung interior doors include the surrounding frame.Homeowners are most likely to need prehung interior doors under certain conditions. You'll need prehung interior doors in locations where no doorframe exists, or when the current doorframe is badly damaged. Slab doors are cheaper and, because most interior doors are lighter than entry doors, they are relatively easy to install if the existing doorframe is in good condition.Need More Help?If you need professional help with your project, LendingTree Home Pros can help.The good news is that LendingTree Home Pros maintains a directory of home service professionals and can match you with a home pro in your area. All the home pros listed in the LendingTree Home Pros directory are properly licensed and insured and are backed by a $10,000 money-back guarantee!Let LendingTree Home Pros help you find a pro today!