As part of the Inside Offsite factory tour programme, precast concrete specialists FP McCann opened up its Byley manufacturing facility to showcase its innovative offsite technology and explain the ways precast concrete is contributing to a more efficient and attractive built environment.
FP McCann has strengthened its structural and architectural precast concrete arm in recent years through a series of acquisitions including Bell & Webster, Bison, Charcon and Buchan Concrete Products. This has secured FP McCann's position as one of the UK's leading construction materials and civil engineering companies and a key player in the precast concrete and offsite markets and a familiar face in the design, manufacture and installation of many p products including internal walls, floors and ceilings panels and its
With a focus on its structural and architectural arm, FP McCann invited a morning and afternoon programme of delegates to tour the Byley facility - now an important element of its modular building network - to see how the largest precast concrete company in the UK operates. FP McCann had a turnover of £226 million in 2017 with precast products making up approximately £165 million, with much of the success and increased market share due to its successful insulated precast sandwich panels.
To keep up with the demands of the construction industry and increasing the capacity of the offsite sector, FP McCann has expanded and increased the scope of its UK production facilities, with further capital investment in new machinery boosting production levels and increasing its structural precast building capacity. "We are expanding and investing in all our facilities," says Daniel Westgate, Commercial Manager, Structures at FP McCann. "Our Byley storage yard is full of sold product - not stock - and one of the things to focus on with offsite manufacture, is that we need a lot of it made before we start onsite, because it goes up so quickly once we start. That is the key advantage over other forms of construction."
The Byley works is producing approximately 12-14 wall panels a day plus 6-8 insulated sandwich panels. If planned for vertical construction the precast panels are always lifted vertically in the factory and stored vertically - likewise if meant for a final horizontal position. The panels are then cured for 28 days before final loading, transportation and installation.
The company has made a new £2.5 million investment to introduce an automatic mesh-bending machine to both improve cost and material efficiencies but also to introduce a more automated approach to create building elements for the burgeoning private rental sector (PRS) market in particular.
"If you look at standard mesh sizes you are always dictated by the bar size in both directions," adds Daniel Westgate. "But on one-way spanning slabs we may want a bigger bar in the direction of span and only a nominal bar perpendicular to that span, so we can offer efficiencies on how we are detailing our reinforcement. The mesh can also be bent which results in a lower quantity of loose steel required to link all of this together, making it more sustainable."
A large and successful element of FP McCann's building solutions are the architectural precast concrete insulated sandwich panels. These are clad either with a brick-facing or can be acid-etched to a huge array of bespoke design specification.
The thickness of the insulation can be modified in order to accommodate any required U-value. The shape, thickness and size of the concrete can also be made to meet the requirements of any project specifics and client requirements. In keeping with all offsite methods, insulated sandwich panels can be used to reduce erection periods by weeks and generally improve onsite safety. The ability to fit various facades, windows and insulation during manufacture also reduces the need for numerous follow-on trades and crucially often eliminates the need for scaffolding.
The insulated precast sandwich panels provide a ready-made external envelope with a variety of finishes. This eliminates many of the pitfalls associated with traditional building methods utilising 'traditional' techniques and employing site-intensive wet trades. The panels comprise an outer leaf of precast concrete, an insulating layer and a structural inner leaf of plain grey concrete that is 'power floated' to a smooth internal finish. The external skin is connected to this and supported by the internal skin using proprietary plastic ties - these have a low thermal conductivity that eliminates potential cold bridging.
"Architecturally and in terms of looks and finish the design options are almost endless," says James Donington, Commercial Manager Architectural Precast for FP McCann. "A brick finish is extremely popular, about 60-70% of every enquiry over the last couple of years has been for a brick 'look'. We can accommodate many different types of brick profile. Bricks that are difficult and time consuming to lay onsite, or complicated bond patterns that are difficult to build neatly onsite, can be cast in our moulds in any order into the panel. This gives a robust finished product and scope to achieve any level of architectural intent."
Finishes include acid-etching, textured, stone-faced or tile-faced, grit-blast or smooth finished including a terrazzo type feel. There are a range of rich finishes to provide an external design and architectural edge including an exposed aggregate finish to create an industrial look.
Also in production at the Byley site is the precast crosswall structural system. This comprises of a series of concrete panels that form the entire building envelope with internal, structural load-bearing and partition walls, external walls and floor slabs. The external walls can consist of just the inner leaf concrete finish or include the insulated precast sandwich panels. "The system is tied in the vertical element using VS loops they interlock with a vertical reinforcing bar that is dropped down that joint. The joints are grouted into the vertical with Thixotropic grout and the horizontal is a CS grout or concrete depending on the nature of the detail," says Daniel Westgate.
Precast in vertical battery moulds - panels of 4m x 10m - can be manufactured 'like toast' that drives costs down and improves speed onsite. They can have conduits and openings for a range of fittings pre-cut and 'cast in' inside the factory, such as openings for smoke detectors. Underfloor heating can also be factory-installed, then pressure-tested in the factory to ensure a reliable defect-free system. Window and door openings are pre-formed in the panels and the window units can be installed at the factory by suppliers to further increase quality.
Central to all offsite methods is the speed of construction. Offsite construction methods ensure buildings can be erected quickly, even in adverse weather conditions, drastically reducing construction time and associated costs and providing quicker return on investment for clients. The benefits are always maximised by early client engagement with the supplier. "What we provide as a business is a design, estimate, manufacture and install (DEMI) service," says Daniel Westgate. "The earlier we can get involved in a project the greater influence we can have on a scheme and make it a success."
FP McCann recently completed a major PRS scheme in Birmingham with the Lansdowne Building - a landmark residential scheme and part of Birmingham's ambitious apartment development programme. Nearly 2,600 individual precast units were installed by the FP McCann contracting team to form the precast structural frame, floors and lower to middle level decorative cladding envelope. The external walls are 410mm thick and of a 'sandwich' construction, with the outer 80mm thick facade consisting of a detailed buff brick design. The facade panels were manufactured at Byley and have been designed to accommodate the two-storey high windows, a unique feature of the building.
For more information visit: www.fpmccann.co.uk
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