What is a Parapet ? Functions and Design Features

A parapet can be defined as a dwarf wall structure or a kind of heavy railing provided around the edge of a roof, balcony, terrace, or stairway. They are constructed in buildings for aesthetics and safety. This article discusses the important functions, and design considerations of a parapet structure.

Fig.1. A Parapet of a Building

Parapets are famous from the medieval era when it was used in castles, towers, and temples, and are now common in our homes. Within these years, their style and purposes have changed. It is also called parapeto in Spain and orbrustwehr in Germany, but shares the same purpose and uses. 

What are the Functions of Parapet?

Parapet roof designs look great and they provide a finished look to buildings with flat roofs. But other than beauty enhancement, parapet walls have certain functions to protect the buildings. They include:

1. Fire Protection

Parapet wall or rails helps to guard the roof membrane against flame. These dwarf walls let the house remain undamaged during small fires. It is not a complete solution for large fires.

2. Wind Resistance

Parapet walls in roofs help to distribute the wind evenly over the roof. They prevent wind uplift that can result in damage to roof shingles. For high-wind areas, parapet designs are a good choice. It is also a proven solution for tornado and hurricane-prone regions. For buildings affected by wind gusts due to any nearby large body of water, these wall units are a good choice. 

3. Protecting Roof from dust, moisture, and debris

4. Prevent unfortunate accidents 

Design and Construction of Parapet

The parapet design is strongly associated with medieval castle architecture, during which it was made from marble. This would give a classic castle architecture feature to the structure. But now, parapet walls are constructed using reinforced cement concrete (R.C.C), steel, aluminum, glass, etc. 

Parapet Wall for Castle

Parapet walls are exposed to extreme weather conditions when compared to other forms of walls. The higher the exposure to dampness, the faster the degradation of the wall components. Hence, parapet must be designed to prevent water from penetrating the supporting masonry wall.

Parapet Wall Affected By Weather- Rain

An adequate water management facility must be provided in the form of copings, damp-proof membranes, and weep holes. Small defects in these regions can result in severe water ingress to adjacent parts of the building.

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Design of Parapet As Per British Standards - Materials and Construction Details