As is nearly always the case, the earlier the specialist contractors are involved, the better and more suitable their part of the project will be. But, just because something is desirable, it doesn’t mean it’s what happens in practice. Andy Pearson reports on the highs and lows of facades.
When it comes to selecting the most appropriate facade solution, main contractors and architects have a lot to gain from talking to the facade contractor early in the project, in a lot of cases at a similar time to discussing the groundworks packages. In most cases, the architect will specify the cladding material and/or the performance criteria that the facade solution must achieve in terms of fire resistance, acoustic performance and the maximum wind loads the system will be expected to withstand. This can also be further complicated by various consultants being involved. The architect may also wish to see two or three different cladding options, which can further confuse the bid process as facade contractors will price a plethora of products. “If a project requires it, we offer the client suggestions for alternative materials or systems that always meet their criteria but which may also deliver additional benefits to the project, such as cost savings, ease of installation or shorter lead times,” said Sam Faux, managing estimator of OCL Facades.
“We were recently asked to look at alternatives to a Glass Reinforced Concrete (GRC) product, whereby we offered a StoneLite Stone Panel solution. This enabled our client to remain on programme due to lead-in times and manufacturing periods, as well as offering cost benefits to the project,” explained Mr Faux. Talking to the facade contractor as early as possible will enable main contractors and developers to benefit from the experience facade contractors have of installing a range of facade systems from various manufacturers.
One increasingly frustrating issue facade contractors are having to contend with is that of the main contractors ‘subdividing’ facade works into smaller packages, such as SFS framing, windows and curtain wall, and facade cladding for installation by individual ‘smaller’ contractors. Mr Faux added that “although on face value subdividing appears to deliver a financial benefit, when you dig deeper and compare all elements, issues can arise between these elements, which then ultimately removes the cost saving achieved at the start”.
Angela Mansell, operations director at Manchester-based Mansell Finishes, commented: “What clients realise is that facade work is structural and therefore specialist. It’s not chunky drywall and often involves design, therefore, it’s essential specialist contractors have the skills to know what they are doing. And working on the outside of the building means higher risk and demands a different way of planning works to internal applications.”
Another issue vexing facade installers is when main contractors and developers leave the appointment of their services until late in the project, by which time much of the facade design has already been developed, often without input of the facade contractor’s experience, particularly on issues such as buildability. As a result, late appointment of the facade contractor can lead to compromises having to be made to the facade because of the limited time available to design and procure the system before installation is scheduled to commence.
Often the reason for a facade contractor’s late involvement is that main contractors have entered into early stage design agreements with facade system manufacturers. The advantage of this arrangement to the main contractor and manufacturer is that the facade design can be developed and agreed with a manufacturer earlier in the programme, eliminating lead-time issues, while the facade installer package is still being negotiated.
This arrangement is not without its issues, though, as Peter Baker, commercial director of Stanmore Contractors, explained. “The problem with this solution is that the facade design may not have been fully coordinated with the windows, fire-break locations or ventilation design, or it may not fully reflect the as-built structure, so there is still an element of design input needed from the facade contractor, but there is very little time in which this input can be accommodated.” Mr Baker continued: “For this reason, the challenge is to persuade clients not to enter into early stage design agreements.”
When contractors are involved at the outset, Mr Baker says that the facade contractor can have “a big influence” on the products used. “Clients do listen to us; while we don’t take responsibility for the performance of products, clients do take on board our knowledge of how products have performed on a previous project,” he explained. “If I’m signing up for design responsibility for a large project, I want to use a manufacturer with good technical support whose products I’ve used before.”
According to Mr Baker, product familiarity is one of the main reasons that Stanmore Contractors’ team of 19 facade designers use just two lightweight steel framing manufacturers and one sheathing board supplier. “It ensures we keep continuity and consistency on all of our jobs,” he commented.
A big advantage of winning the SFS facade contract is that it gives the contractor a shout at the project’s drylining package too. Mr Baker added: “A lot of clients want a one-stop-shop for facades and drylining.”
Combining facade and drylining packages can also be advantageous for the project. “Most high-end residential buildings in London have a floor screed these days, so if we’ve got the drylining package as well as the facade package we can almost dictate our own programme,” Mr Baker explained. “It means we can get the framing system up and the sheathing boards fitted to make the floors semi-watertight, which allows us get our screeding and drylining teams underway.”
Ms Mansell agrees that the need to make a building watertight early in the construction programme is important and that the choice of sheathing solution depends on the building height. She said: “18 metres is key. Over this (height), it must be a non-combustible and proven weather-resistant board – some gypsum-based boards have limited life span when exposed to weather.”
Manufacturers too are offering a one-stop-shop for lightweight facade systems and drylining packages. Knauf, for example, has launched its ThroughWall Solution. This is a synthesis of various existing Knauf systems to produce a complete facade and drylining system. “With the exception of the finishing cladding, we supply all of the components that fit behind it, including the sheathing board, metal infill framing system, insulation, etc. – even the plasterboard,” said Charles Johnston, business development director for facades at Knauf.
Mr Johnston says the advantage of having a single supplier and one point of contact for the external and internal elements of a project is that it “reduces the design risk and adds to the ease of interface between the envelope and the internal drywall package to deliver optimal acoustic performance as well as excellent fire, thermal and airtightness performance”. Similarly, it should mean that if problems do arise in both the specification and installation process, remedies can be supplied from Knauf alone, rather than the blame being shifted from one manufacturer to another.
A similar offering is expected from the Etex Group following its acquisition of EOS Facades. Etex already owns drywall product manufacturer Siniat and passive fire protection specialist Promat. Following the acquisition, the company has set up Etex Building Performance to create innovative new solutions aimed at reducing installation times. “By combining forces, we will provide pioneering solutions and industry-leading technical expertise,” said Neil Ash, former head of Siniat UK who is now the new head of Etex Building Performance UK. Watch this space…