Doors are one of the most basic components of any habitable space and are usually installed for providing security, protection, and privacy from external elements as well as internal activities. Doors can be typically described as building components that allow movement between two physically separated spaces. Hence, depending on their position and the nature of the space, doors can be described as exterior door or interior doors. Unlike external doors, internal doors are primarily installed with a view of separating spaces of different nature and provide privacy. Interior doors are pretty similar to external doors, however, there could be small differences in the locking systems, thickness of door panel, fixing mechanism, fire and acoustical insulation. Interior doors are primarily fabricated from wood, although, glass, plastic, as well as metal are also highly popular since these different materials tend to add a new texture to the interior design of the house. Similar to any other component within the house, the design and feel of internal doors too is largely governed by the overall style and colour combination that is dominant in the surrounding spaces.
Solid flush door
These are the most common types and consist of a framework of wooden stiles and rails covered with sheets of plywood or MDF to achieve a flat surface. These kinds of doors are relatively inexpensive and provide good levels of space separation and privacy. The fire and acoustical rating of these doors can be further improved by addition of door seals and fire rated wooden components.
These are doors that are provided with horizontal slats and are usually fixed within the main door frame. The louvers could be of the same material as the main door or of a different material. These doors do not offer good acoustical insulation or privacy, however, they are excellent for spaces which demands good ventilation levels. As a result of this, louvered doors are very common in kitchens, bathrooms, store rooms, etc. The louvers are typically positioned near the bottom of the door, however, louvers near the top are also common. Depending upon the ventilation requirements, the louvered doors can be provided with an exhaust fan for added efficiency.
Transparent / translucent doors
These doors could be a combination of solid frames and transparent / translucent glass panels or simply a glass panel without solid frames. These types of doors are one of the most common type of internal doors owing to their visual appeal and ease of availability. Depending upon the type of the panel, these doors could be fixed on a basic pin hinge or on floor hinges and patch plates. These doors provide good acoustical insulation and depending upon the type of glass you can enhance the level of privacy it offers. Door designers typically opt for stickers or etched patterns at the eye level in order to allow light to pass through but at the same time provide some privacy to the users within the space.
Butt hinges or pivot hinges are the most commonly used fixing hardware for interior doors. In the case of glass doors, the door panel is supported on a top patch plate and bottom floor hinges. The numbers and type of butt hinges are typically governed by the opening width and the weight of the door. Modern hinges are typically made of stainless steel, although, different metals are also fairly common.
The sliding door mechanism was introduced for two main reasons. First was to allow installation of doors in extremely tight spaces and second was to facilitate fixing of large doors which would typically be beyond the holding capacity of butt or pivot hinges. Sliding doors open and close on a linear axis which is parallel to the opening in the wall and are usually fixed on top rails and bottom guides. In the case of internal doors, designer try to avoid the bottom rails in order to allow the users a smooth and undisturbed floor level. Although efficient, the sliding door hardware is much more complicated and expensive than a typical butt hinge and benefits from periodic maintenance. Based on the availability of space and user requirements, the sliding doors could be exposed or concealed in a pocket which is mostly the wall cavity.
The first thing to consider is the opening size and the nature of the space. This will allow you to decide the type of the door panel whether solid or transparent, and the fixing mechanism whether hinged or sliding. Next, you might want to take a look at the security aspects, you can opt for a typical key-hole lock or an electronic lock if you want to keep records of the people who enter through the door. You should also consider the requirement of a door closer. In the case of doors mounted on floor plates, by default there is a closer since the floor plate has a spring which gets the door back in its closed position. However, in the case of butt hinges, a door closer could be useful since you do not have to worry about closing the door every time you open it. This is particularly helpful if the space is air conditioned or if the air quality of the room and the space surrounding it is different.