When Should Scaffolds Be Designed?

When Should Scaffolds Be Designed?


We are often asked if particular scaffold arrangements ‘need’ to be designed. The HSE has compiled a list of scaffold arrangements they would expect to see. Confusion arises from the existence of TG20 guidance documents and historical practice within the industry. ‘TG20:08 A guide to good practice for Scaffolding with Tubes & Fittings’ is a document derived from ‘BS EN 12811 Temporary Works equipment – Scaffolds’ – the British Standard for the design and erection of scaffolds.  TG20:08 attempts to interpret the requirements of BS and provides guidance notes for good practice in the design and erection of scaffolds.  In addition to this, it reproduces several design tables from which the intention is certain configurations of the scaffold, if meeting the configuration arrangement, do not require any further design.  Unfortunately, this has added to the confusion. 

TG20:08 is very specific and prescriptive in the requirements of scaffolds which can be erected without further design such as where they are, the wind load on them, a maximum of 2m bays, a maximum of 2m lifts and whether they are netted or sheeted etc.  Although your configuration may meet all the criteria, our guidance is – What does your Customer want?   

You can argue the configuration does not require a design as it is TG20 compliant but if they want a design then you’ll have to do one anyway!  Besides, there aren’t many large Contractors who would allow scaffolds to be erected on CDM sites without one, as they are often used for their own H&S and TWC management and they often need them to co-ordinate all trades who will be using the scaffold. 

Scaffold structures that need to be designed 

  1. Dead Shores  
  2. Flying shores  
  3. Raking shores  
  4. Cantilevered scaffolds  
  5. Truss-out Scaffolds 
  6. Access Birdcages 
  7. Façade retention  
  8. Access scaffolds with more than the 2 working lifts allowed with TG20 ‘Basic Scaffolds’ 
  9. Buttressed free-standing scaffolds  
  10. Temporary roofs and temporary buildings  
  11. Support scaffolds  
  12. Loading Bays founded on the ground  
  13. Mobile and static towers outside base/height limitations  
  14. Free standing scaffolds outside base/height Limitations  
  15. Temporary ramps and elevated roadways 
  16. Staircases and fire escapes  
  17. Spectator Terraces and Seating Stands  
  18. Bridge scaffolds  
  19. Towers requiring guys or ground anchors  
  20. Offshore scaffolds outside Offshore Contractors Association (OCA) handbook  
  21. Pedestrian footbridges or walkways  
  22. Slung and Suspended scaffolds  
  23. Protection fans, Nets and Pavement Frames  
  24. Marine scaffolds  
  25. Boiler scaffolds  
  26. Power line crossings  
  27. Lifting gantries and towers  
  28. Steeple scaffolds  
  29. System scaffolds outside users guide parameters  
  30. Sign board supports  
  31. Sealing end structures  
  32. Temporary Storage on Site 
  33. Masts, Lighting Towers and Transmission Towers 
  34. Advertising hoardings/banners  
  35. Any scaffold structure subject to:  
  • Vibration  
  • High Loading  
  • Long term duration  
  • High risk areas  
  • Loading from passenger/goods hoists  


Extracted from the HSE website. 


Read more Technical Guidelines.