Because doors are highly visible, hardworking parts in a home’s interior, they deserve thoughtful attention when it comes time to buy new ones. The right doors will stand up durably to daily usage, minimize sound transfer between rooms, and add character or style to the home’s overall interior design.
Interior doors come in two basic types: flush and panel.
Flush doors (shown below right) have flat, smooth surfaces that are typically painted or stained with wood stains. They are basically nondescript and, as a result, blend in with a home’s interior (unless that interior is quite traditional or classic).
Hollow-core flush doors, installed in millions of homes for the past 50 years, are lightweight, low-cost versions of the flush door. These have an inner softwood frame surrounding cardboard honeycomb cores, and are faced with thin wood veneers. They are damaged relatively easily and allow considerable sound transfer.
Those surfaced with lauan mahogany veneer have particularly soft surfaces that do not receive finishes very well. Surface veneers of birch or other hardwoods are stronger and take stain or paint better.
Panel doors (shown below left) are made from a framework of horizontal rails and vertical stiles that frame flat or raised wood panels or, in some cases, glass panes. This construction method is common for solid-wood doors because it minimizes the effects of wood’s tendency to shrink, warp, and swell with variations in humidity.
The best types are built with precisely fitted, interlocking sections, and they are significantly more expensive than flush doors. A good, less expensive alternative with much the same look as a wood door is a medium-density fiberboard (MDF) door. This type is solid and won’t swell or bind. In addition, it takes a finish well.
Although new wood doors are sold unfinished and must be stained or painted, MDF doors come primed and ready to be painted.
Standard interior doors are 1 3/8 inches thick and 6 feet 8 inches tall. You can special order taller doors but, if you do, be prepared to pay a premium.
Standard interior door widths run from 24 inches wide (used for closets and small bathrooms) up to 36 inches. A door that is 36 inches wide is necessary for handicap accessibility.
If you’re planning new doorways, be aware that many furniture pieces are too large to pass through doorways that are less than 30 inches wide.
Interior doors are sold pre-hung in frames or as doors only, called blanks or slabs. The latter type are for hanging in existing door frames or for mounting in a situation where the interior carpenter is up for the challenge of building the entire jamb set. They are sold without hinges, knobs, or locksets, but they may be ordered with a hole pre-bored for the lockset.
Pre-hung doors are the preferred choice in most situations because of the labor they save. The door comes mounted to a jamb set, with hinges mortised into the edges. When ordering this type, you specify the surface-to-surface thickness of the wall and the size and location of the holes for the lockset.
There are several types of interior doors, distinguished by the way they operate. Here are the most common ones:
Hinged doors are the standard in every home. Conventional hinged doors may be either right or left handed. A door that opens toward you and has the door knob on the right is right handed. A door hinged on the opposite side is left handed.
Folding doors are often used to conceal a wide space where a conventional door’s swing would be awkward or restricted. Mounted in hinged-together pairs, folding doors combine the actions of both sliders and hinged doors, using both end pivots and overhead tracks.
Bypass doors, often used on closets or storage areas, are lightweight indoor sliders that hang from rollers that run along an overhead track. They’re typically mounted in pairs or threes; they bypass one another to allow access.
Pocket doors are another type of slider that is ideal for places where there isn’t room for a door to swing. A pocket door slides into a space, or “pocket,” that is installed in the wall.