6.1 External masonry walls
This chapter gives guidance on meeting the Technical Requirements for external masonry walls.
Introduction#
This chapter provides guidance on external masonry which is used for the outer and inner leaves of a cavity wall construction, cladding to framed structures and to the limited solid wall construction used in housebuilding such as garages. General guidance on masonry cavity wall construction including the masonry inner leaf of a cavity wall are also provided within this chapter.
The guidance is consistent and complementary to that provided within Chapter 6.9 Curtain walling and cladding which should be used for products and systems falling under that description.
There is a strong link to all chapters in Part 6 of this standards, particularly Chapters 6.2 – 6.5, 6.10 and 6.11.
The aim of this chapter is to provide clarity for external and cavity walls constructed of clay and concrete bricks and blocks as well as natural stone.
Definitions for this chapter#
Aggregate concrete masonry unit | Masonry unit manufactured from cementitious binder, aggregates and water and which may contain admixtures and additions and colouring pigments and other materials incorporated or applied during or after unit manufacture |
Aircrete masonry unit | Masonry unit manufactured from hydraulic binders such as cement and/or lime, combined with siliceous based fine material, cell generating material and water and cured with high pressure steam in autoclaves |
Blocks | Masonry units which when used in its normal aspect exceeds the length or width or height specified for a coursing unit (typical brick size). A common block size is 440mm long x 100mm wide x 215mm high |
Bricks | Are designated in terms of their intended use. The coordinating sizes for bricks is generally: 225mm long x 112.5mm wide x 75mm high. The work sizes are in effect coordinating sizes less a nominal thickness of 10mm for the mortar joint |
Clay masonry unit | Masonry unit made from clay or other argillaceous materials with or without sand, fuel or other additives fired at a sufficiently high temperature to achieve a ceramic bond |
Coastal locations | A site within a distance of 500m from the general coastline of the United Kingdom |
Compressive strengths | Where these are quoted in this chapter, they refer to the declared compressive strengths of masonry units |
Coordinating size | Size of a coordinating space allocated to a masonry unit including allowances for joints |
Coursing unit | Masonry unit, commonly of brick sizes, used to assist in achieving the storey height of a wall in conjunction with full height blocks |
Fully filled cavity | The insulation thickness is such that the it will be in full contact with both leaves of masonry when the building meets normal construction tolerances |
Manufactured stone masonry unit | Facing masonry unit having at least one exposed face with a close structure formed from either one or two homogeneous mixtures of aggregate, cementitious binder and other materials moulded under pressure and/or vibration and with or without further processing, intended to resemble and be used as an alternative to natural stone |
Masonry | Assemblage of masonry units laid in a specified pattern and joined together with mortar |
Masonry unit | Preformed component intended for use in masonry construction |
Natural stone masonry unit | Masonry unit manufactured from natural stone |
Recessed joints | Where the mortar is raked out, about 5 mm from the wall face. There are certain exposure conditions where these should not be used (clause 6.1.6) |
Work size | Size of masonry unit specified for its manufacture, to which the actual size conforms within permissible deviations |
Clauses for 6.1 External masonry walls
- 6.1.1 Compliance
- 6.1.2 Provision of information
- 6.1.3 Structural design
- 6.1.4 Fire resistance
- 6.1.5 Acoustic resistance
- 6.1.6 Exposure
- 6.1.7 Thermal insulation
- 6.1.8 Concrete blocks
- 6.1.9 Bricks
- 6.1.10 Stone masonry
- 6.1.11 Construction of masonry walls
- 6.1.12 Lintels
- 6.1.13 Materials suitable for mortar
- 6.1.14 Mortar
- 6.1.15 Render
- 6.1.16 Cladding
- 6.1.17 DPCs and cavity trays
- 6.1.18 Wall ties, bed joint reinforcements and windposts
- 6.1.19 Handling materials
- 6.1.20 Protection of the works during construction
- Figure reference table
Last updated: 2nd January 2024