Types and Terminology of Sofa Parts

Living room furnished with white seats

Hickory House

A sofa is made up of many different parts. And all these different parts can vary from sofa to sofa, giving each a distinct look and feel. Knowing how to identify each main part and its variations can help you describe the sofa you want to a salesperson or designer. Understanding the basics of sofa construction can make you a shrewd judge of sofa quality.

Sofa Arms

The arms define the ends of a sofa and play a critical role in the overall look and function of the piece.

  • English arm: An English arm is low and is set back from the front edge of the seat. English arms are low-profile and suitable if you like to take naps on your sofa. They are also good for small spaces, as they don't project beyond the body of the sofa.
  • Pleated arm: The front part of a pleated sofa arm is covered by fabric that is continued from the inside of the arm.
  • Rolled arm: A very common traditional shape for sofa arms, a rolled arm curves outward. Although comfortable for lounging and reading, rolled arms do take up extra space and should be taken into account when measuring a sofa.
  • Lawson arm: A Lawson arm is a low-profile, modestly scaled version of the rolled arm.
  • Square arm: Also called a box arm, a square arm gives has a modern, tailored look, with straight lines and angles. Square arms are useful for entertaining, as they can serve as seats. However, they are not as comfortable as rolled arms for lounging.
  • Tuxedo arm: Tuxedo arms are slightly flared arms that have the same height as the sofa back.

    Sofa Backs

    Sofa backs can vary in height, shape, and cushion material and are integral to the style and comfort level of a sofa.

    • Attached back: Attached back cushions are fastened, clipped, or sewn to the back of the sofa. The advantage is that they don't move around and you don't have to worry too much about keeping them in shape.
    • Camel back: A camel back is a traditional sofa back that is shaped much like a camel's hump, raised in the middle, and sloping down lower at the ends. It often imparts a formal look.
    • Channel back: Deep vertical grooves on a tight back are the distinguishing features of a channel back.
    • Loose-cushion: Loose cushions are separate from the sofa back, as opposed to attached back sofas. This allows for covers to be easily removed for cleaning.
    • Curved back: The back of a curved-back sofa curves all the way around so that it forms one solid piece with the arms, which are not attached separately.
    • Pillow back: A pillow back sofa has more pillows than seat cushions, and therefore a softer feel. This style offers comfort that can also be adjusted by moving the pillows around. It does require more upkeep, though.
    • Tight back: A tight back in a sofa is upholstered but does not have loose cushions. The back has a firm feel and can provide a clean, tailored, and formal look.​
    • Waterfall back: A waterfall sofa back has two or more vertical layers of gathered and billowing cushions that are attached to the back.

    Sofa Seats

    Sofa seats are more than just places to discover lost items. The right feel of a seat is critical to your enjoyment of a sofa.

    • Cushioned seat: A cushioned seat is usually made up of two or three cushions. Since these cushions are made to support the weight of the sitter, they are usually firmer than back cushions. The cushions may be square or rectangular, depending on the number of cushions on the seat. Sometimes the end cushions are T-shaped to accommodate the arms. Cushioned seat covers typically are removable.
    • Single-cushion seat: Oftentimes a sofa seat will have just a single cushion. This is also called a bench seat. A single-cushion seat offers a tidy, minimal look but also can be combined with a pillow back, which is more about casual comfort than minimalism. When you sit down on one end of a good single cushion, it will not rise up on the other end.
    • Tight seat: Sofas that have no separate seat cushions are often called tight seat. This style can be found both on traditional and modern sofas or sofas with wood frames. It is generally conveys a formal look.

    Sofa Construction

    "Under the hood" of your sofa are the various parts that make up its structure. These are largely responsible for the longevity of a sofa.

    • Deck: The deck is the surface that lies directly underneath the seat cushions.
    • Down-proof ticking: Ticking is the inner lining of a cushion, usually tightly woven, that helps keep tiny down feathers from moving to a cushion's exterior.
    • Eight-way hand-tied springs: Tied springs are connected to one another with strong twine that runs front to back, side to side, and diagonally in both directions. This construction interconnects the springs for durability and even support.
    • Filling: Filing may be foam, down, or padding that is used to make the sofa comfortable.
    • Frame: The frame comprises the bones of a sofa and determines not just the shape but also the quality. High-quality sofas have kiln-dried hardwood frames with strong, reinforced joints.
    • Plinth base: Instead of conventional legs, a plinth base is a box-like base often found on contemporary sofas.
    • Webbing: Webbing consists of interwoven strips of synthetic material, attached to the wood frame of a sofa. It is typically used in place of support springs.