Rendering refers to the process of applying a thin layer of a mixture of cement, sand, and water to the exterior walls of a building. The mixture, called render, is applied in a wet state and then left to dry and harden. The render is applied in a thin layer, typically around 15mm to 20mm thick, and it is used to provide a smooth and even finish to the walls.

Rendering can be used to improve the appearance of a building, as well as to protect the walls from the elements. It can also be used to improve the insulation of the building by adding an additional layer to the walls.

There are several types of render that can be used, including:

• Sand and cement render: This is the most common type of render and is made from a mixture of sand, cement, and water. It is typically applied in two or three coats, with the first coat being scratch coat and the second and third coat being a finishing coat.

• Lime render: This type of render is made from a mixture of lime, sand, and water. Lime render is more flexible and breathable than cement render, which makes it less likely to crack or spall.

• Monocouche render: This is a premixed type of render that comes in a dry form and is typically applied in one coat. It has a smooth finish and comes in a variety of colors.

• Synthetic render: This type of render is made from a mixture of synthetic materials and is usually applied in one coat. It is a lightweight and easy to apply option and it also comes in a variety of colors.