A dado rail, also known as a chair rail or surbase,^[1] is a type of moulding fixed horizontally to the wall around the perimeter of a room. The dado rail is traditionally part of the dado or wainscot and, although the purpose of the dado is mainly aesthetic, the dado rail may provide the wall with protection from furniture and other contact.

In cities such as Bath, England, the dado rail has been used in architecture to imply parts of the classical order. According to author Micahel Forsyth, "The dado, including skirting and dado rail, represents the pedestal, the wall surface the column shaft, and the cornice the entablature."^[2]

Modern trends have been towards 36 inches (910 mm),^[3] based on the assumption that its purpose is to protect the wall from chair backs. The term chair rail is also used for this reason.

Dado rails are also sometimes applied to a wall without the full dado treatment. The purpose of the rail in these cases may be protective, and it is common in environments where walls are subject to much wear and tear, such as shopping centres and hospitals. In such cases the height of the rail is often 1,200 mm (47 in) or even 1,500 mm (59 in) from the floor and serves a functional rather than aesthetic role.

The dado rail is a decorative and functional architectural element that is designed to divide the wall into distinct sections and protect it from furniture or other potential sources of wear and tear. It can be used for colour blocking, additional definition and to pay homage to the original architectural details of the property.^[4]

Dado rails are produced using a variety of materials, each offering unique benefits depending on the intended aesthetic and functional requirements:

• Wood: Traditional dado rails are crafted from solid hardwoods such as oak, pine, or mahogany. These materials are highly durable and lend a timeless appearance, making them particularly suitable for restoration projects and period properties.
• Medium-Density Fibreboard (MDF): MDF is a cost-effective and widely used material for dado rails in modern interiors. It is easy to cut, resistant to warping, and can be painted to suit a variety of décor styles.
• Plaster: In historical buildings, plaster dado rails are often molded directly onto walls, blending seamlessly with other decorative architectural features such as cornices and friezes.
• PVC or Plastic: Commonly used in commercial spaces or high-traffic areas like hospitals and shopping centers, these materials are durable and low-maintenance, prioritizing function over aesthetics.

The placement of a dado rail is significant for achieving both aesthetic balance and functional utility. Traditionally, dado rails are installed at a height of 900 millimetres (35 in) to 1,200 millimetres (47 in) (35 to 47 inches) above the floor, aligning with the historical purpose of protecting walls from chair backs. However, modern applications may vary depending on the room's proportions and design preferences.

One method for determining the ideal height involves dividing the total wall height by five and doubling the result. For instance:

• A wall height of 2,400 millimetres (94 in) divided by five equals 480 millimetres (19 in). Doubling this value places the dado rail at approximately 960 millimetres (38 in) above the floor.

This calculation ensures visual harmony by dividing the wall into proportionate sections. For homeowners seeking precision, tools like dado rail height calculators can assist in determining optimal placement.^[5]

Dado rails may also be installed without the full dado or wainscot treatment, serving a purely decorative purpose or providing wall protection in areas subject to frequent wear and tear. For example, in high-traffic spaces like hallways or dining rooms, the material and height can be adjusted to match the room's style and functional needs.

• Picture rail

• The Misused & Confused Chair Rail by Brent Hull, December 3, 2010, at This Is Carpentry