Security Hacks

Parts of a Door: All You Need to Know [With Diagram]

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A front door with a terrace and windows next to it

If you’re wondering what the different parts of a door are, you’ve come to the right place. 

No matter if you need to maintain or repair your existing unit, understanding the anatomy of a door is crucial.

Once you understand the importance of the individual door components and how they work together, you will be able to spot arising issues much easier.

Keep reading to learn everything you need to know about the different parts of a door.

Here’s an illustration that summarizes the most important door parts:

A diagram showing the different parts of a doorPin
This diagram shows the main door parts

Door Frame

In a nutshell: The main job of a door frame is to provide structural support for the door. It also secures the door in place and prevents it from warping.

No door works without a frame. This structural component is an essential part of any entrance as this is what supports the entire door.

What are the main elements of a door frame?

It’s typically made up of a head, also called a horizontal lintel (at the top), a sill (at the bottom), and two parallel jambs. These three units create a complete door frame. Typical door frame dimensions are 80 inches high by 36 inches wide.

Wood, mainly pine, is probably the most common material used for door frames, however, plastic, steel, and composite materials are not uncommon either.

The door frame is not only an important structural component, but it also sets the tone for the overall look of the door.


In a nutshell: The door jamb is the two vertical sections of the door frame, and it provides structural support to hang the door. Additionally, it serves as a seal between the wall and the door.

Door jambs and door frames are often confused. So, what exactly is a jamb?

The vertical elements of a door frame that you can find on both sides of a door are known as a door jamb.

Thus, the door jamb is an integral part of the door frame. Its main job is to support the door and keep it in place.

All exterior and interior doors are hung on hinges mounted on the door jamb.

Not the hinges are the only hardware that is installed on a door jamb: the strike plate, another essential part of any door, is also located on it.

There are two main types of door jambs: rabbeted and plain.

Rabbeted jambs are the most common type and they have grooves called rabbets which can be single or double. Double rabbeted jambs have two rabbets (1 3/8″ and 1 3/4″), allowing them to fit almost any interior door opening (1).

Rabbeted jambs are typically made of pine, poplar, or other wood species.

In addition to providing a functional role, the door jamb can also play a role in the appearance of the door.


In a nutshell: The primary job of door hinges is to control and allow doors to open and close. They provide support to keep it securely in place when closed. Hinges also ensure doors maintain their graceful balance when opening or closing, keeping them from recklessly swinging too far in any direction.

Door hinges anchor doors to the door frame, allowing them to gracefully open and close. This hardware is typically composed of two metal plates, one attached to the door and the other to the frame, that effortlessly twirl around a central pivot point like a screw or pin.

There’s a whole troupe of door hinges, each with its own specialty. The most popular is the classic butt hinge, commonly seen in homes and businesses, gracing both interior and exterior doors.

But there are also pivot hinges, security hinges that add an extra layer of protection, continuous hinges that flow seamlessly along the length of the door, and the elusive concealed hinges that disappear into the background. So, whether you’re looking for style, security, or a little bit of both, door hinges have got you covered.

These are the main parts of a door hinge:

  • Leaves: The two metal plates that are attached to the door and the door frame.
  • Knuckles: The rounded or cylindrical parts of the hinge that connect the leaves to the pin.
  • Pin: The metal rod that connects the two leaves and allows them to pivot around it.
  • Screws: The fasteners that hold the hinge leaves in place and secure the hinge to the door and door frame.

Lock Set

In a nutshell: A lock set secures a door and prevents unauthorized entries.

The lock set is like a guard at the door: it secures the door in a closed position, so only those who have the key can enter. This hardware device can restrict access to either a room or an entire building.

A door lock set is made up of a few key components, like a latch, a keyed cylinder or a thumb turn for ease of access, a door handle, and a strike plate.

It can also include a deadbolt which provides additional security for those who need extra peace of mind. All of these parts work together in harmony to keep the door secure.


A door latch is an essential part of a door. It keeps the door safely closed, and it’s directly operated and engaged by a door handle, such as a knob or a lever. It’s usually mounted on the surface of the door panel.

One main part of a door latch is the bolt, which is a metal bar that extends into a strike plate (a metal plate over a mortise on the door jamb) when the door is closed.


Deadbolts are supplementary locks that may be installed on any door, whether it be an interior or exterior one, for added security and safety. Typically, a key is used on the exterior to unlock the device, while a door knob or lever is used on the inside. It is often keyed and installed above the latch.

Door deadbolts are a typical component of home security systems since they can prevent forced entry and are difficult to pick.

Main types of deadbolts:

  • Single-cylinder deadbolts: These can be unlocked and locked with a key only from the outside. If you’re inside, you can use a thumb turn.
  • Double-cylinder deadbolts: This type of deadbolt can only be opened with a key from both the inside and outside.   


A cylinder is a vital component of every keyed lock. Along with the keyway, it houses the mechanism that allows the lock to function properly.

The cylinder is the component of the lock set that really allows you to lock and unlock the door when you turn the key.

Strike Plate

A strike plate is usually a rectangular metal plate that is mounted on the jamb over a mortise. It’s an essential door component. Its main function is to reinforce the part of the door jamb into which the bolt extends.

Handle or Knob

All doors have some kind of handle that you grasp to open or close the door. The two most common types of handles are doorknobs and levers.

When you turn or press a handle that will activate the latch mechanism. As a consequence the latch bolt retracts and the door can be opened.

This brings us to the end of the main parts of a lockset. If you want to know all parts of door locks and door knobs, check out this article.

Door Panel

In a nutshell: The main function of a door panel is to provide privacy by separating interior and exterior spaces. A good-quality door panel also improves security and contributes to soundproofing and insulating the building.

A door panel is the core part of any door. Wood, metal, composite (like MDF), or plastic (like UPVC) are common materials for this component, which is fastened to the door frame.

The door panel may be found in many different forms; typically, it is chosen for its aesthetic appeal and how well it fits in with the building’s overall architectural scheme.

Glass Panels

In a nutshell: A door glass panel has many functions, such as allowing natural light to pass through, providing a view to the outside, and improving the appearance of the door.

A glass panel, also known as glazing, is the part of a door that’s made of glass. So it’s basically a piece of glass incorporated into the door.

Many types of glass panels exist, such as laminated, tempered, tinted, insulated, or wired (2). Glass panels can be either framed by a metal or wooden mullion or unframed.


In a nutshell: A transom provides additional natural light and sometimes also allows ventilation.

A transom is a small horizontal glass panel that is located above the door.

Mullion (Mull)

In a nutshell: It adds stability to the individual glass or other kinds of panes of the door and keeps them in place.

A mullion is a vertical or horizontal bar that separates two or more individual panels. It’s often made of wood, plastic, or metal. Some mulls are for decorative purposes only.


In a nutshell: Sidelights help to brighten up the room behind the door by allowing more natural light in. Often they’re also used for decorative purposes.

Sidelights are fixed narrow glass panels located on either side of a door. They can be either a single glass pane or multiple panes.

These narrow windows provide additional natural light, and they also serve as decorative elements. Sometimes sidelights are combined with transoms to make the glass surface even larger.


In a nutshell: Support and stability are two of the key core functions of a door’s rails. They also contribute significantly to the door’s aesthetics in general.

The horizontal parts of a door, called rails, provide the basic structural backbone of the unit. They are fastened to the stiles of the door (on the top and at the bottom as well). The material that they are typically constructed of is usually the same as that of the rest of the door.

Rails, in addition to their structural importance, also contribute to the appearance and style of the door.


In a nutshell: Like the rails, stiles provide stability to the door and they help prevent warping and other deformations.

A stile is a vertical component of a door panel that runs along the sides of the door. The stiles are typically attached to the rails. They’re a crucial part of any door.


In a nutshell: A threshold provides a weatherproof barrier and seal, thus it helps prevent rain, dust, and other elements from entering your home.

The threshold is the horizontal piece of the door that’s located at the bottom of the door frame. It sits on the sill and provides a seal and a physical barrier between the inside of your home and the outside world or between different floorings.

Thresholds are usually made of wood, metal, or composite materials.


In a nutshell: It has a structural role as it’s required for any door to function properly. It also provides a barrier.

A sill is a horizontal piece of a door that sits at the bottom of the door frame on the foundation of the floor.

Door Closer

In a nutshell: It prevents the door from being in an open position and it also ensures that the door closes smoothly at a controlled speed. Therefore it helps to improve energy efficiency.

A door closer is a mechanical device (mainly hydraulic, spring-loaded, or pneumatic) that is mounted on the door and door frame and closes the door automatically in a smooth way when it’s in an open position.


In a nutshell: The casing gives the door installation a polished appearance by hiding any gaps that may be present. Additionally, it shields the wall from any possible harm that might be caused as a result of the door being used.

The molding or trim that surrounds the door frame all the way around is called the casing. It is usually made of wood, plastic, or metal, and it covers the space between the door frame and the wall.


In a nutshell: The main function of brickmold is to provide a transition between the door frame and the surrounding wall.

Brickmold is a type of casing that provides a boundary between the door frame and the brick or masonry surrounding it. This door part is installed around the outside perimeter of the door frame.

Weatherstripping and Sealing

In a nutshell: The primary purpose of weatherstripping and sealing is to obstruct the passage of cold (or hot) air, water, dust, and other contaminants from the outside world into the house via cracks and openings around the door.

By installing weatherstripping, you can keep unwanted elements from entering your home. It also helps you reduce your cooling and heating costs.

Many types of weatherstripping exist on the market, such as foam tape, V strip, rubber, silicone, or felt. They’re all designed to create a tight seal around the door.

Kick Plate

In a nutshell: A kick plate protects the bottom part of a door. 

A kick plate is a metal (stainless steel or aluminum) or plastic plate that is installed at the bottom of a door to protect the door from scratches and other damages. They are typically installed on commercial doors such as those in schools, hospitals, and businesses.

Frequently Asked Questions

What is the strip at the bottom of a door called?

In most cases, it’s called a door sweep or door seal and it’s usually made of some kind of plastic material, such as nylon. The main function of this seal is to block water, dust, and air from entering the door.

What holds the door in place?

The most important hardware elements that hold a door in place are the hinges, which are attached to both the door and the door frame and allow the door to swing.

What is the piece called that the door knob goes into?

The piece that the door knob goes into is called a door latch. The doorknob and the latch are directly linked with each other. So when you turn the knob, the spindle retracts the latch bolt. The latch sits inside the borehole.

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About the Author

James Mora is the founder of DailyHomeSafety. He is a home improvement expert, contractor, avid DIYer, and security manager. He is passionate about home repairs, remodeling, and teaching. Read More