6.5 Steelwork

6.5.5 Padstones

Steelwork shall be supported by padstones where required to distribute point loads safely to the supporting structure without undue movement or deflection.

Where a steel beam is supported by masonry, a padstone may be required to spread the load over a larger area to prevent overstressing. Padstones should be in accordance with:

  • the engineer’s design, or
  • the guidance given in this chapter.

Where the inner leaf of the cavity wall contributes to the overall thermal performance of the wall, padstones should:

  • have similar thermal properties to the masonry used for the rest of the inner leaf, or
  • not create a cold bridge.

Table 6: Size of padstones (for steel supporting partition walls)

Notes

1. Padstones are not necessary where the flange dimension of the beam exceeds the length of the padstone given in this table.
2. When steelwork is in line with the wall supporting it, ie, when acting as a lintel over an opening:
– the flange dimension of the beam should not be more than 50mm greater than the thickness of the supporting wall
– the minimum length of padstone should be 200mm
– the padstone depth should match the coursing of adjacent masonry
– the web of the beam should be over the centre of the wall.
3. The minimum length of steel bearing onto padstone should be 100mm.

Table 7: Size of padstones (for steel supporting floors)

Notes

1. Padstones are not necessary where the flange dimension of the beam exceeds the length of the padstone given in this table.
2. When steelwork is in line with the wall supporting it, ie, when acting as a lintel over an opening:
– the flange dimension of the beam should not be more than 50mm greater than the thickness of the supporting wall
– the minimum length of padstone should be 200mm
– the padstone depth should match the coursing of adjacent masonry, and
– the web of the beam should be over the centre of the wall.

Padstones should be formed in one unit with a minimum compressive strength of 10 N/mm2 from:

  • in-situ concrete
  • precast concrete
  • concrete blocks
  • clay bricks, or
  • engineering bricks (when less than 215mm x 100mm).

Last updated: 2nd January 2024

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