MULTIPLICITY OF TRADES

The multiplicity of trades on a construction site is probably the key issue in the process which leads to poor quality and time delays. In traditional construction procurement a client appoints a professional team, including architects and engineers to develop a design for a building. This is then tendered to a main contractor. In order to deliver the project, the contractor breaks up the design into key elements which are sub-contracted to trade suppliers who specialise in such elements.

It is not uncommon for the elements defined by the main contractor to be then broken down further within the sub-contractor chain. Coordination and sequencing of the interfaces between the elements in this chain becomes one of the crucial challenges for the main contractor. Mistakes will lead to abortive and corrective work on site and additional costs to be incurred. At each layer of sub-contract, any element of uncertainty is priced as ‘risk’ and contract management is required. These risk and management costs all feed back up the chain meaning that the cost to the client is inflated. One client I have spoken to has estimated that for a contract where £6,000,000 of product is procured from suppliers, he was paying £10,000,000. A closer relationship directly with suppliers is important to clients.

In addition to this designers are often not aware of exactly how a building will eventually be sub-contracted which also means that the interfaces in a project which may later turn out to be critical are poorly communicated which adds to the uncertainty and potential for mistakes.

In essence this is the challenge that Modern Methods of Construction (MMC) seeks to resolve. It will be interesting to see how Design for Manufacture and Assembly (DfMA) changes the procurement model. Could designers be appointed by offsite manufacturing companies? Will clients go direct to these firms?

Perhaps the new role of ‘integrator’ will be created. This specialist would effectively form a link between client and suppliers, ensuring that all components for the construction, whether built off site or installed on site, are interfaced appropriately to ensure a positive outcome.