6.5 Steelwork


This Chapter gives guidance on meeting the Technical Requirements and recommendations for steelwork to support masonry partitions, timber floors and to trim floor voids.


6.5 - D1Design standards
6.5 - D2Structural design
6.5 - D3Padstones

6.5 - D1
Design shall meet the Technical Requirements

Design that follows the guidance below will be acceptable for steelwork supporting either masonry partitions or floors.


6.5 - D2
Steelwork shall be designed to support and transmit loads to the supporting structure without undue movement or deflection

Steelwork (including its support and any connections) should be either:

  • designed by an Engineer in accordance with Technical Requirement R5, or
  • where appropriate, detailed according to the designs shown in this Chapter.

The designs shown in this Chapter are in accordance with BS 5950 using grade 43 steel and therefore meet statutory requirements.

It should be noted that the information given in this Chapter has been prepared primarily to assist builders in providing proper support to masonry partitions and floors. The designs given will not always be the most economic and an engineer may be able to design a smaller section beam for a particular situation.

Items to be taken into account include:

support of masonry partitions

Where appropriate, masonry partitions may be supported by steelwork selected in accordance with Appendix 6.5-A.

Care should be taken during construction to avoid the problem of out-of-true masonry being only partly supported by steelwork.

support of floors

Timber floors can be supported by steelwork.

Where appropriate, steelwork should be in accordance with Appendices 6.5-B and 6.5-C.

The timber floor should be in accordance with Chapter 6.4 'Timber and concrete upper floors' (each section), including proper allowance for shrinkage of timber joists supported by steelwork.

Support of floors

support of steelwork

Steelwork may need to be supported on padstones to distribute loads safely.

Masonry should be in accordance with Chapter 6.1 'External masonry walls' (each section) or Chapter 6.3 'Internal walls' (each section), as appropriate.

steelwork to steelwork connection

Connections between steel beams should be designed.

Where appropriate, steelwork beam-to-beam connections should be in accordance with Appendix 6.5-C.

Appendix 6.5-C uses bolted connections (using black bolts) or welding. Connections requiring the use of other forms of connection (such as high strength friction grip bolts) should be designed by an Engineer in accordance with Technical Requirement R5.


Steelwork should be given a protective coating system to ensure durability. For details, refer to Sitework clause 6.5-S3.

fire resistance

Steelwork should be provided with the level of fire resistance required by Building Regulations.


6.5 - D3
Padstones shall distribute point loads safely to the supporting structure

Where a steel beam is supported by masonry, a padstone may be required to spread the load over a sufficiently large area of the masonry to prevent overstressing. A padstone may be necessary (see Table 3, Appendix 6.5-A and Table 5, Appendix 6.5-B for sizes).

Where the inner leaf is used to provide a major contribution to the thermal insulation of a cavity wall, any padstone that is needed should have similar thermal properties to the masonry used for the rest of the inner leaf or precautions should be taken to prevent cold bridging.