All the Parts of a Door You Need to Know
Get your foot in the door by knowing these terms
Highlights
A door includes the slab, frame, and rough opening studs.
The parts of a door determine its style, function, and cost.
There are variations between exterior and interior doors, as well as their framing.
It's best to hire a professional to install a door from scratch for proper function.
As an active and curious homeowner, understanding the parts of a door can get you out of a lot of jambs—ahem, jams. Whether you're learning how to build a door from scratch, repairing a faulty door, or getting ready for a new home construction, you'll need to know how each part of the door contributes to the whole. Let's fling the door wide open on all the terminology you need to know.
Main Parts of a Door
We'll begin as zoomed out as possible. Similar to any structure, it's best to talk about the overall terms related to door anatomy and then break down individual parts of each of those sections. Here's what to know.
Door Slab
The door slab—or door panel—is the main rectangle that swings back and forth. The material and style of your door slab have a large say in your door installation costs. Exterior doors are often more solid and weatherproofed, while interior doors are lighter and occasionally hollow. They will also either come pre-hung or as a solid slab.
Door slabs may include windows, locksets, hinges, mullions, and a variety of specialty parts. We'll dive into the parts of the door slab later.
Door Frame
The door frame connects your door panel to the structure of your home. Door frames break down to the door jamb, the sill, the threshold, weatherstripping, stops, and strike plate hardware. Surrounding the door frame are the casing and the brickmold, which support the frame on the inside and outside of the home. We'll break down all of these below.
Rough Opening
Just outside of the door frame, the rough opening of your wall refers to the cut that makes way for the whole installation. If you're starting from scratch, you'll need to know the supporting parts of the rough opening. These include the top and sole plates, the king and jack studs, the cripple studs, and the header. More on these in a minute.
Parts of a Door Slab
Time to take a closer look at the parts of the door slab. In most cases, you will not need to build the slab itself, but knowing its parts can help you align it correctly and get to know available styles.
Stiles and Rails
On a basic level, stiles are the external vertical sections of a door panel and rails are the external horizontal ones. When broken down further, you'll find a top and a bottom rail as well as a hinge stile and a lock stile. As the names suggest, the hinge style contains the hinge hardware and vice versa.
Mullions and Midrails
Set inside the stiles and rails, you'll find the mullions—or mulls—that make up the vertical sections in the center of a door. The midrail—or lock rail—crosses the middle of the door horizontally, connecting the hinge and lock style.
Panels
The pieces set within all of the framing of the door panel—everything listed above—are called panels. In some cases, door panels are swapped out for windows, lighting, or decorative accents.
Bore Hole and Lockset
Depending on the placement and type of door you choose, there will be a bore hole for either a knob and/or a lockset. The types of locksets include basic knob locks, hand levers, and deadbolts. Door knob varieties also vary, ranging from dummy door knobs for decorative purposes and knobs with a keyhole.
Hinges
Hinges connect one side of the door panel to the frame so that the door swings open and closed. You can choose from several types of hinges, including ball-bearing hinges, butt hinges—the most common type—spring-loaded hinges, and more. These hinges determine whether the door is self-closing and whether it swings in one or both directions.
Specialty Parts
Door styles come in countless shapes, sizes, and functions, so you'll also find these terms incorporated into door anatomy:
Kick plate: Door kick plates protect the base of a door, particularly on the outside of an exterior door. Made of metal, plastic, or vinyl, the thin panel covers a rectangle of space on the base of the door.
Transom: Transoms are a line of individual windows that sit above a door, typically framed individually and set within the rough opening of the wall.
Astragal: The astragal seals the space between two doors, typically two sliding or French doors.
Sidelights: Many exterior doors have narrow panels and/or windows on either side of the door to extend the full installation. These are known as sidelights.
Parts of a Door Frame
What about the door anatomy surrounding the door panel? If you're not impressed by the number of new words on your vocab list yet, get ready. Thankfully, there will not be a quiz.
Door Jamb
Even though the terms get tossed around interchangeably, a door jamb and door frame are not the same thing. The door jamb includes the two vertical and one horizontal piece that immediately frames the door slab. The door jamb includes a hinge jamb, a latch jamb, and a head jamb—each sitting where their name implies.
Sill and Threshold
Door sills and thresholds sit along the floor and the base of the door's opening. A sill attaches directly to the rough opening of the floor for an exterior door. A threshold goes over the top of the sill to both protect its structure and make the transition look more stylish. Exterior sills and thresholds typically slant outwards to prevent water from coming inside. On an interior door, you will often only see a threshold between two rooms.
Stop
Also known as rabbets, stops are pieces of material that keep a door from swinging too far. The placement of the rabbet determines the style and function of the door. Some doors sit flush with the opening while others have a space between the frame and the slab, for example.
Weather Stripping
Door anatomy includes several areas of weather stripping depending on the door's placement around and outside your home. Exterior doors include weather stripping around the entirety of the jamb. You will also find a door sweep—or weather stripping along the bottom of the door slab.
Casing and Brickmold
The panels of wood, metal, or vinyl that cover the gap between the door frame and rough openings are known as casing or brick molding. Casing refers to the frame around the interior of the door and often matches the interior style of the door. Brick molding, on the other hand, refers to the frame on the outside of the door. Despite its name, brick molding comes in a range of materials, often ones strong enough to seal and weatherproof the gap.
Strike Plate
Last but not least, your door frame will include a matching strike plate to line up with the door panel's lockset and knob. A metal strike plate increases the strength of the long and adds an ornamental touch to the opening.
Parts of a Rough Opening
If you're installing a new door to a wall or observing the new construction of a home, you'll get a view into the rough opening of your door. As we mentioned earlier, a series of studs offer the necessary support to the wall so that your door melds with the structure of your home.
Top and Sole Plates
The top and sole plates sit at the top and bottom of the entire rough-opening door structure. The vertical studs of your wall and door attach to these two plates or the 2-foot by 4-foot board.
King and Jack Studs
Studs are the vertical support that carry the load of your ceiling. King studs run the length between the floor and ceiling while also supporting the sides of Jack studs. Jack studs run the length of your door and stop at the header.
Header
The header is the 2-foot by 4-foot board that frames the top of a door's rough opening. In some cases, the header and the head jamb are the same, but it depends on the structure of the rough opening. The header attaches to the king and jack studs that run vertically on either side.
Cripple Studs
How about that space between the header, the ceiling, and the top of the jack studs? The cripple studs are the shorter 2-foot by 4-foot boards that vertically support the space above the door and under the ceiling.
Installing a Door
While knowing all of the different parts of a door can help you with some DIY installation projects, it's best to call a local door installation team to handle any structural changes to your home. Hanging a door incorrectly can come with expensive and even unsafe consequences. However, there are some DIY-friendly designs, such as installing a door jamb or installing a pocket door to keep on your project list.