Structure: Approved Document A

O N L I N E V E R S I O N A1/2 THICKNESS OF WALLS IN CERTAIN SMALL BUILDINGS Diagram 1 S ize and proportion of residential buildings of not more than three storeys See para 2C4 Thickness of walls that the number of wall ties per square metre is not less than 2.5 ties/m2. Wall ties should also be 2C5 General wall thickness may be determined provided, spaced not more than 300mm apart according to this section provided: vertically, within a distance of 225mm from the a. conditions relating to the building of which vertical edges of all openings, movement joints the wall forms part (see paragraphs 2C4, and roof verges. For selection of wall ties for use 2C14 to 2C16, 2C38); and in a range of cavity widths refer to Table 5. For specification of cavity wall ties refer to paragraph b. conditions relating to the wall (see paragraphs 2C19. 2C17 to 2C37) are met. (See Diagram 3.) For external walls, compartment walls and 2C6 Solid external walls, compartment walls separating walls in cavity construction, the and separating walls in coursed brickwork or combined thickness of the two leaves plus 10mm blockwork: Solid walls constructed of coursed should not be less than the thickness determined brickwork or blockwork should be at least by paragraph 2C6 and Table 3 for a solid wall of as thick as 1/16 of the storey height. Further the same height and length. requirements are given in Table 3. 2C9 Walls providing vertical support to 2C7 Solid external walls, compartment other walls: Irrespective of the material used walls and separating walls in uncoursed stone, in the construction, a wall should not be less in flints, etc.: The thickness of walls constructed thickness than any part of the wall to which it in uncoursed stone, flints, clunches, bricks or gives vertical support. other burnt or vitrified material should not be less than 1.33 times the thickness determined 2C10 Internal load-bearing walls in brickwork by paragraph 2C6. or blockwork (except compartment walls or separating walls): All internal load-bearing walls 2C8 Cavity walls in coursed brickwork or should have a thickness not less than: blockwork: All cavity walls should have leaves at least 90mm thick and cavities at least 50mm (specified thickness from Table 3) – 5mm wide. The wall ties should have a horizontal 2 spacing of 900mm and a vertical spacing of 450mm, or alternatively should be spaced such Continued on page 17 Structure Approved Document A 14 O N L I N E V E R S I O N