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RCI January 2018

Working with contractors: Part 2 In the second instalment of two articles – See November 2017 for Part 1 – Jim Hooker, SPRA technical director explores the changing face of procurement and In part one, I outlined how SPRA offers how SPRA has responded in terms of support during construction guidance and standards to support the design and specification stages. But what about the construction process? Good design and appropriate specification generally encourages a good standard of construction. This is because it allows the specialist to work in a familiar environment, with adequate space in which to install and with adjoining elements properly sequenced and detailed. But this is not always the case. Most failed jobs arise from a combination of incorrect circumstances, especially weak site management. So how can SPRA help to avoid these? Protection Following discussions with several tier one major contractors, SPRA published Protection of single ply roofs – Guidance and checklists (available by free download from www.spra.co.uk). This takes a practical look at the avoidance of damage in design, sequencing and construction. There are five checklists applicable throughout a project together with a toolbox talk: 1. Design. 2. Pre-start agenda. 3. Temporary and permanent protection. 4. Site management. 5. Contractual arrangements. One challenge is to find a suitably sustainable product that meets the need for a robust, easily handled but re-useable temporary covering. A move away from unwieldy and wasteful plywood or OSB is essential, but linkable alternatives in rigid thermoplastic are not yet available. SPRA has employed recycling experts Axion Consulting to research options for reuse of roofing product with the aim of creating a micro circular economy in this roofing sector. 044 JANUARY 2018 RCIMAG.COM Sequencing The overriding prerogative tends to be a weatherproof roof, as early as possible in the programme. The notion that a complete roof system must be installed, with all the risk of damage, should be challenged at an early stage to see what two-stage options are available. For example, a temporary vapour control layer and membrane flashings can be installed to allow cladding and wet trades such as rendering to proceed, before completion of the system when there is least risk of damage. Inspection and Test Plan (ITP) Clearly, the primary responsibility for quality control rests with the roofing sub-contractor, but exactly what form this takes must be agreed prior and reflected in the Contract. An ITP will include a programme for sign-off and testing and for subdivision of large or multiple roof areas. The ITP should also include daily weld tests, which are retained, and suitable photographs to record the condition of the site at key stages. SPRA research would suggest these are often overlooked by main contractors, leading to protracted dispute in the event of problems. So where does that leave the membrane manufacturer’s inspection, which is mandatory under SPRA membership rules, for all projects of more than 100m²? The inspection should ensure that the manufacturer’s warranty is not compromised by poor workmanship; that their registered contractor has a satisfactory quality control regime and that the installer(s) of the single ply membrane have current productspecific cards. Informally, it is an invaluable route for feedback on issues of buildability, technique and appearance and an opportunity to check that recently trained or assessed installers are getting along well. But the manufacturer’s inspection is a snapshot of work areas (where accessible and SPRA MATTERS Left: Other trades may not understand roofing technology and how to respect it “The overriding prerogative tends to be a weatherproof roof, as early as possible in the programme”


RCI January 2018
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