Steel Beam Web Hole Opening

Structural calculations for web openings and strengthening

We provide structural calculation checks and strengthening design for large service holes through steel beams to meet Building Regulations (calculations to BS5950 or Eurocode 3).

Our Structural Engineers will check your beam based on the specific beam, loading and hole requirements of your project.


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Includes structural calculations and drawings

suitable for submission to Building Control

Holes through steel beams

Holes through steel beams, or 'web openings' are often required to allow larger services to pass through, such as soil pipes, air conditioning ductwork etc.

Steel beam arrangements in loft conversions often create challenges when routing shower waste or soil pipes and creating a hole through a steel beam can provide a solution.

Allowable hole size

Reasonably large holes can be made through the web (the vertical stem) of a steel beam before reinforcement is required, depending on the beam load.  Calculation should always be carried out to confirm adequacy of the arrangement for the applied loading - Building Control will usually request justifying calculations.


See the diagram below for recommended maximum hole  sizes, positioning and spacing.

Round web opening
Rectangular strengthened web opening
Web Openings - Recommended Geometry limits: (based on SCI P355) 

Compliance with geometry limits does not assure structural adequacy - calculation checks required.


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