Robin Horton, Sales & Marketing Manager, Coltman Precast Concrete Ltd, Outlines Some Of The Benefits Of Precast Concrete Flooring.
Over the past 40 years or so there has been an increasing shift to concrete flooring – particularly in commercial and industrial buildings. Some of the key reasons for this continuing growth can be summed up as sustainability, innovation and health & safety.
Sustainability is in many ways an obvious feature since it is one of the principal features of concrete as a material. Its 'shelf life' can be measured in decades rather than years and, what’s more, it can be broken up when no longer required and recycled in a variety of ways; including use as an aggregate for new concrete.
In terms of innovation, there are now many variations, each offering particular benefits for specific individual applications.
Health & Safety
Last, but certainly by no means least, there is health & safety – a vitally important area that is at the heart of the work of the Precast Flooring Federation (PFF – www.precastfloors.info), as well as being a critical consideration for us at Coltman Precast Concrete.
Whilst product developments and innovation still continue, there are currently three main generic types of precast concrete floor: hollowcore, beam & block and lattice girder.
Of these it is hollowcore which is proving the most popular for commercial buildings. Hollowcore flooring consists of concrete elements cored along their length, with units generally available as 1,200mm wide – although some manufacturers produce up to 1,500mm, or as narrower units of 600-750mm width. Depths are 100-400mm, depending on the span and loading conditions; providing efficient, flexible solutions across all markets for most building types.
An often over-looked benefit of concrete floors is the improved acoustic performance. With today's generally increasing environmental noise, any such improvements are most welcome.
Concrete floors are also more cost-effective than timber and enable thinner floor zones, as well as longer spans. In addition, they provide a safe working platform for ongoing construction work.
Add to that their intrinsic one hour minimum fire resistance and compatibility with other precast concrete components such as stairs and balconies and it is easy to see why the technique continues to gain ground.
Another more obvious plus for concrete floors is the ability to vary room layouts without worrying about floor loadings. This feature applies particularly at first floor level and above, avoiding any concern about the positions of supporting walls. For the designer this flexibility and adaptability provide yet more factors in favour of concrete.
Precast floors can normally span greater distances than timber or steel, supporting higher loads with reduced floor depths, and this impacts significantly on the overall design of supporting structures and foundations.
The use of precast flooring allows flexibility and choice in layout and adaptability. Members of the PFF, such as Coltman, can provide a complete service from the conceptual design stage through to on-site structural solutions – a package approach that is already commonly used in the commercial sector with great success.
Speed of supply and installation is another factor to be considered. Precast hollowcore flooring is, by definition, manufactured off site and delivered 'just in time'; with, typically, installations being undertaken within one day. Many floor specifications can be available within days rather than weeks and simple installation techniques enable up to 350 sq m of hollowcore to be installed in a day.
As the acknowledged leading force in the industry for health & safety, the PFF recognised the dangers of working at height very early in its existence and has for many years produced a regularly updated and revised Code of Practice For The Safe Erection Of Precast Concrete Flooring And Associated Components. This takes into account developments such as Work At Height Regulations 2005, CDM Regulations 2007, Health & Safety In Construction 2006, and Noise At Work Regulations 05 has recently been introduced.
Like its earlier editions, the latest revised Code of Practice is designed to be used as the basis for the training of erectors, foremen and supervisors to ensure that they all have the skills and competence to carry out their respective roles in a safe and efficient manner.
The revised Code has been some two years in preparation, assisted throughout by members of the Health & Safety Executive (HSE). Whilst primarily available as a download from the PFF website, a number of looseleaf ring-binder copies are being made available.
A recent £3.5 million project at Innova Park, Enfield, constructed by ROK on behalf of SDG Enfield Ltd, incorporates Coltman precast hollowcore units for the upper floors of two separate two-storey office buildings, and which comprise of ten individual units.
The overall floor area of the development is 28,636 sq ft, with car parking and associated access roads, paved areas, landscaping, incoming services and ancillary works. As the foundation is piled with ground beams, no deep excavations were required for the substructure. The incoming services include the provision of a new sub-station to service the site with capacity and cabling to supply a further development.
The design, manufacture and installation of approximately 1,270 sq m of 1,200 mm wide precast prestressed hollowcore flooring units – 150 mm and 200 mm deep – were carried out along with ten staircases.
One of the integral safety features adopted was the use of the Airtek TruckMat passive fall-arrest system, both on site and, when possible, around lorries. The system which is based on inflatable mattresses has been tested in conjunction with the Building Research Establishment (BRE) and the British Safety Council (BSC), and is accredited by both.
Established in 1972, Coltman Precast Concrete's product range includes prestressed hollowcare wide slab and solid prestressed wide slab for flooring and roofing. Staircases, landings, balconies, terracing and wall units are also available as bespoke products.
As a major independent supplier to the housing, commercial, industrial, health and leisure sectors nationwide, Coltman produces in excess of 250,000 square metres of prestressed hollowcore flooring and 4,000 cubic metres of bespoke concrete products each year.
Customers include some of the leading names in architecture, construction, civil engineering, house building and property development. The company has been involved in numerous prestige projects, ranging from multi-million pound city centre redevelopments and quality housing, to civic cultural centres and premier sports arenas.
Coltman offers a complete supply and fix service, from initial design through to installation by its own CITB trained site teams, fully compliant with all the appropriate regulations and utilising the very latest safety equipment and procedures.
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