Temporary demountable structures (TDS) - stages, seating, marquees etc

What you will find on this page

Information to help those organising events to manage the safe erection, use and deconstruction of temporary demountable structures (TDS).

Your duties as an event organiser

Construction roles and duties

What you should know

Most fatal and serious injuries arise when workers fall during construction work or as a result of the collapse of the structure, lifting operations or mobile plant.

Checklist – TDS dos and don'ts



  • Consider what the structure will be used for, what it needs to be able to do, who will use it and how?
  • Prepare a clear specification for the structure's required use. This should include the technical details required to enable a design to be undertaken by your appointed TDS contractor(s) / designer (s).
  • TDS contractors / designers hired to design, supply, build, manage and take down a structure for you, should be competent and adequately resourced.
  • Provide TDS contractors / designers with relevant site information and/or allow them site access to carry out their own site assessments.
  • Your TDS contractor should ensure that the proposed structure has a design prepared by a competent person, which takes account of the use and conditions in which it is to be installed.
  • Where a structure is to carry advertising / scrim, include this requirement in any design concept, specification and structural assessment.
  • Novel or unusual structures may require additional testing by a TDS designer to demonstrate the integrity of the design.
  • Whoever builds the structure should undertake an assessment of the likely construction hazards and risks. To help with an assessment and to find out more about construction hazards and risks see:
  • Plan and work with your contractors to develop safe systems of working and make sure all significant risks on the site are properly controlled, eg use of cranes and lift trucks.
  • Plan to minimise confusion and conflict, particularly between those contractors carrying out concurrent or consecutive activities on the same structure.
  • Consider the extent of control that you and your contractors have over the work activity and workplace during each phase of the build, use and deconstruction cycle of a structure. Organisers and TDS contractors should agree the extent of their control at the planning stage, so that responsibility for structural safety is understood and maintained throughout the event.

Building and dismantling the TDS

  • The assessments done under Planning (above) should serve as a guide on how to build and dismantle the structure safely.
  • Make sure there is sufficient time and resources available to build and dismantle the structure safely.
  • Use competent staff and have a suitable onsite operational management system in place to supervise and monitor safety compliance.
  • A programme of works, including key safety checkpoints, can be helpful to communicate critical erection / dismantling stages to the site manager / crew bosses and operatives.
  • Build the structure to the agreed design in accordance with a safe system of work.
  • Arrange for the structure to be checked to make sure that it has been built according to the design.

While TDS is in use

  • Have arrangements in place to inspect the structure for deterioration during the time it is installed in line with a documented management plan and, if needed, arrange for remedial works.
  • Any change in the proposed use of the structure or site conditions which may affect the structure's suitability should trigger a design check for the new conditions. An example of this may be the requirement to add additional banners to a structure such as a PA tower. The organiser is responsible for ensuring this is done.
  • Have arrangements in place to ensure that any measures required to keep the structure safe during use are implemented. For example, if the structure is susceptible to the weather, monitor and measure the local weather conditions. In adverse weather conditions, know what to do with the structure to protect its stability, eg when to open wind relief panels and when to evacuate.  


  • Take forward incomplete design concepts, as this could result in last-minute modifications, leading to safety problems.
  • Build a structure on unstable ground.
  • Put advertising / scrim on a structure if a competent person has not approved it as being safe – it can affect wind loading and increase the risk of collapse / overturn.
  • Use flammable fabrics.

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Updated 2024-02-09