External wall

Approved document C, Site preparation and resistance to contaminants and moisture, suggests that a wall is: 'Any opaque part of the external envelope of a building that is at an angle of 70° or more to the horizontal.'

An external wall is a wall forming the external enclosure of a building.

Approved document B, Fire Safety, Volume 2, Buildings other than dwellinghouses (2019 edition), suggests that the external wall of a building includes all of the following:

• Anything located within any space forming part of the wall.
• Any decoration or other finish applied to any external (but not internal) surface forming part of the wall.
• Any windows and doors in the wall.
• Any part of a roof pitched at an angle of more than 70 degrees to the horizontal if that part of the roof adjoins a space within the building to which persons have access, but not access only for the purpose of carrying out repairs or maintenance.

This definition is also found in the Building Regulations 2010 and this is referenced by The Higher-Risk Buildings (Key Building Information etc.) (England) Regulations 2023.

NB RICS property measurement, 2nd edition, published by the Royal Institution of Chartered Surveyors (RICS) in January 2018, defines an external wall as: ‘The external enclosure of a Building, which comprises the area between the Internal Dominant Face and the outside of a Building.’

[edit] Related articles on Designing Buildings

• Barrier wall system.
• Brick.
• Building fabric.
• Building Safety Act.
• Cavity wall.
• Coping and capping
• Curtain wall.
• Diaphragm wall.
• Dwarf wall.
• Façade.
• Load-bearing wall.
• Palisade.
• Rainscreen.
• Rubble masonry.
• The Higher-Risk Buildings (Key Building Information etc.) (England) Regulations 2023
• Wall.
• What are walls made of?