Spec Finish

Technical i www.thefis.org 13 photographically. However, both types must be signed off by the relevant competent persons. JC: The FIS Advisory Service is often asked to evaluate the quality of a finish where there is a dispute, yet in the majority of cases this could have been prevented by providing a finished area as a benchmark before the work started. How could contractors approach this where there is no mention of a benchmark in either the contract or a specification? AD: The quality of finish, be it tape and jointing or plaster skimming are probably the most disputed items on a project, and this is because the approach is often more subjective rather than objective from each party involved. A benchmark is a ‘friend’ and will assist in the smooth running and completion of a project, hopefully with no disputes. If benchmarks are not mentioned in a specification or the contract, it is advisable that you proactively offer this as part of your works, and once constructed, accurately record what was agreed and with whom. You should also understand who should sign off these benchmarks. This may require not only the main contractor to accept, but also the designer and the client etc. Always insist that all parties involved in the sign off process agree and accept the quality of finish at the earliest opportunity. JC: Quality can be objective and also subjective where expectation can cloud decisions to accept a finished piece of work. What advice would give to those inspecting as well as to those installing the materials? AD: Firstly, understand the standards you are being contracted to construct to, and this should be noted in the specifications. This could be British/ European Standards, NHBC Standards, manufacturers’ recommendations and legislative requirements. If you don’t have a copy of these standards and guidance, ensure you obtain them, read the documents and fully understand what is expected of you. If there are no references to the standards in the contract documentation, then you should advise your client in writing which standards you will be using as the basis of the installed works (in conjunction with the manufacturer’s recommendations). For example, drylining tolerances are stated in BS8000-8 and BS 8212, plastering tolerances in BS EN 13914-2 etc. The quality of tape and jointing and drylining installation will be objective as these can be physically measured against prescribed dimensions. The finish of plaster skimming on the other hand is more subjective . However, there is invaluable guidance on the flatness, smoothness and inspection regimes to be employed when inspecting this type of work. For example, when inspecting plasterwork for acceptance, surfaces shall be viewed from the positions normally used in the adjacent area – this would be from the entrance doorway and from the centre of the room in a normal domestic house and from about two metres away from the surface in larger areas. This is stated in the British Standards and should be used by both the installers and by those inspecting the works to ensure a similar approach is taken. Check the final lighting conditions (natural and artificial) and always install the works using supplementary lighting which is adequate to facilitate the production of a good standard of finish. If there are any omissions in the standards or the specifications for any items requiring inspecting, this can also be benchmarked and agreed. JC: We talk a lot about the importance of providing technical benchmarks in the Best Practice Design and Installation Guide, Firestopping of Service Penetrations, ( www.thefis.org/membership-hub/ publications/best-practice-guides/ firestopping-of-service-penetrations ) , how and where would you suggest they are used? AD: Technical benchmarks provide a number of useful purposes: • they can demonstrate the technical competence of the subcontractor and show they have the knowledge and understanding of how systems are constructed; • they can also be useful to understand how a detail may work on site with all of the building tolerances factored in; and • they provide a useful point of reference throughout the project so the site team know ‘what good looks like’. It is always recommended that both the manufacturer and competent persons check the technical benchmarks, and this is particularly important when fire performance is required. With firestopping benchmarks, we would always recommend a sample wall (or floor) is constructed with all penetration seals installed in this area (where practicable to do so), and this can be used as a control sample for all to see and understand. Sample areas may only be possible on larger projects, however, a benchmark of each type of penetration seal should always be provided and signed off by the relevant competent persons. Samples and benchmarks can also allow for any early warnings if there are any problems or spatial reasons why the design may not be possible. benchmark [ˈbɛn(t)ʃmɑːk] NOUN benchmarks (plural noun) 1. a standard or point of reference against which things may be compared. “the pay settlement will set a benchmark for other employers and workers” synonyms: standard · point of reference · basis · gauge · criterion · specification · [More] 2. a surveyor’s mark cut in a wall, pillar, or building and used as a reference point in measuring altitudes. VERB benchmarks (third person present) 1. evaluate (something) by comparison with a standard. “we are benchmarking our performance against external criteria” A sample of a penetration seal system FIND OUTMORE www.thefis.org/knowledge-hub/technical