RoundTable Event - Saving Energy Saving Money
Fabric First has long been the heartbeat of the timber sector as energy efficiency and building performance consistently challenge the construction sector. A Roundtable Event hosted by DuPont tackled what the timber and offsite sector can do better for the environment and building owners and occupiers.
When the Zero Carbon Hub closed for business in March 2016 alongside the earlier shelving of the Code for Sustainable Homes (CfSH) some important initiatives were lost trying to tackle the UK’s carbon reduction targets. While government incentives surrounding micro-renewables and energy generation grabbed the headlines, the real long term benefits have always been about getting the building designed and built correctly from the start – a Fabric First approach.
But there is a feeling that this path to energy conservation has slipped off the construction agenda in the race to deliver ultra high energy efficient properties, with energy efficiency issues not being dealt with at an early stage and often being addressed later in the construction process. “Fabric First is what we talk about,” says Bradley Cameron, UK Business Development Manager for DuPont. “What we often see is ‘Fabric Last’. Developers have built something then have to ‘wrap it up’ which causes problems and is an expensive thing to do, rather than getting it right in the first place. If you don’t get that right, then the amount of insulation you end up using doesn’t work like it should.”
Adopting a Fabric First approach initially rather than as a secondary consideration is central to achieving maximum energy and building envelope performance. This is where factory-based offsite design is increasingly important and there is real merit in aligning the timber industry and linking Fabric First thinking to a design for manufacture and assembly (DfMA) approach and the huge airtightness, thermal and acoustic gains.
“There were important elements built into the CfSH Level 4/5 that offsite and timber systems gave you for free,” says Stephen Wightman, Managing Director of SIG Offsite. “Airtightness and acoustic benefits were already delivered in the factory. This offers the opportunity to force value from the way we build. Traditional construction is having to add this into their equation – if we can push that agenda again – these costs are already built into our products and processes – it’s a free enhancement.”
Timber and offsite manufacture are delivering energy efficiencies almost by default and in many respects are in the DNA of the material and process delivery, but has that Code-driven thinking fallen out of favour – is it still important to deliver to a particular energy performance level? “It is all about value,” says Peter Barr, Managing Director of Innovaré Systems. “It was knocked down the agenda as people found it difficult to see and demonstrate the value that it gave. It didn’t give a short term return – the payback was over a 5/10 year period.” Unless that value is clearly demonstrated – or an asset holder can monetise it – it can be difficult to pin down and truly understand. For commercial clients and housing developers and in particular social housing providers that hold housing stock, the value of building with a Fabric First approach with a 60 year payback is difficult to grasp. But for the everyday individual buying a property – perhaps just on the strength of an energy performance certificate (EPC) – it’s seems to be outside the current culture of UK housebuyers.
The concept of energy efficiency over the lifetime of a product and whole-life costs are difficult to demonstrate and evaluate. Impressing on everyone operating in a largely cost-driven construction culture, that small upfront premium capital costs can be recovered over time, based on energy performance benefits and reduced running costs is difficult. “Even within social housing, there is a slight disconnect,” says Tony Woods, Technical Manager at LHC. “It can be a bit disjointed between the teams building the stock and the teams looking after it. They have no control over what components are going in and what is being used. But when whole-life costs are considered as opposed to pure build costs you realise the benefits of better quality products.”
The energy targets on thermal, acoustic and airtightness that the CfSH contained focused minds but perhaps focused them in the wrong places. For many the Code was overcomplicated and was misleading on the scoring weighting of energy performance – which was roughly only about 30% of the marks. “In a way the Code got corrupted,” says Andrew Orriss, Sales Director, SIG360. “It changed from a ‘code for sustainable homes’ to meaning ‘energy efficiency’, that seemed to be the reference point. It was really about sustainable living – flexibility of space and lifetime homes.”
So while it wasn’t perfect, the Code was a benchmark and framework to apply optimal levels of performance but the awareness of the ‘replacement’ Home Quality Mark from BRE – which ultimately is about engaging the consumer with its star rating – has seen the construction industry in some ways contract back to basic Building Regulations and ‘obsession with airtightness’. Are clients knowledgeable enough to balance of all the performance and technical criteria from a design perspective and educate clients on a Fabric First approach? Something that homeowners with a vested interest in the running costs of the building and lifetime performance of their homes seem to understand better – especially the self-build sector. “If a self-builder is choosing SIPS for example,” says Kevin Platt, Technical Director, SIPCo. “They really do the research and are well-educated on U-values and you need to prove your performance up front.”
A key discussion surrounds ‘design versus as-built’ and closing the performance gap – typically a 20% difference in performance. Even with the greatest fabric design and offsite manufacture efficiencies, the construction process onsite can be fraught with difficulties and educating follow-on trades and installers is vitally important. Poor site work has consequences that can be largely unknown and difficult to monitor and ruin the precision controlled products and systems that leave the factory gate – the management and installation of systems have to be done correctly to maximise the benefit of Fabric First.
“The perfect fabric can be developed and then follow on trades come along and traditionally put holes in place they shouldn’t,” says David Ewing, Head of Guidance at LABC. “A role for building control and at inspector level is to audit or validate that what was designed and what was delivered are the same thing. Material substitution also can cause huge problems. The whole sub-contractor environment needs to become more joined-up so they can better understand the products they are working on.”
Lifting performance above the minimum standards in a cost driven environment is something the construction industry strives hard to achieve. For many the appointment of a Housing Ombudsman is closer than ever to ensure better, fit-for-purpose performance and avoid some of the problems of the magnitude that Bovis Homes have suffered in recent months. A central aspect of improving performance is gathering and using performance data proficiently. Much talk focuses on data harvesting and the huge amounts of information drawn from building monitoring. Embedding sensors within the building fabric and responding to the data received is central to process, product and system improvement and developing a correct response to environmental changes – e.g. temperature changes when windows are open or closed and day/night temperature shifts.
“Digital connectivity and technology can make this all happen with smart meters and the measurement of wind speeds or moisture content,” says Stephen Wightman, Managing Director, SIG Offsite. “The level of automation is there and embedded data in houses can be fed back into the inspection process. This would be beneficial and prove what is actually being done.”
Predictability is at the heart of Fabric First and offsite manufacture. However, the potential for problems that arise when the products leave the factory and enter the uncontrolled environment of the construction site, added to issues surrounding interoperability within the timber frame and wider offsite industry, then the risks for failure increase exponentially. There are many firms thinking they have a unique proposition with their system or product, when in reality it is virtually identical to most others on the market – this is causing confusion. Manufacturing is driven by standardisation and interchangeable components that reduce costs and provide certainty in the event of needing to change suppliers and manufacturers if companies fail. When this occurs intellectual property is often lost and is difficult to substitute with other products. So a more joined-up, collaborative approach across the whole sector is required. “Products are only a small part of the equation,” says Peter Blunt, Managing Director of Innovaré Systems. “It is about the process outside the factory. More collaboration will add more value to the industry – all these tiny details – nobody really cares. Clients want to see an integrated approach.”
The future of Fabric First looks healthy. While ‘codes and marks’ come and go, the motivating concept of delivering energy and thermally efficient buildings is something the timber sector is constantly striving to achieve. But to really maximise the potential of timber technology and the associated products used with them, is an agreement of sorts based on better collaborative R&D. Innovation is not done in isolation but in wider dialogue with architects, structural engineers, developers and contractors. “It also needs to be tied into warranties,” says Matt McColl, Associate, Pollard Thomas Edwards. “NHBC and Building LifePlans for example need to be involved as ultimately that is what the big housebuilders are interested in. They need to be heavily involved in those discussions so we can get to a point as an industry where everyone is on the same page.”
Many thanks to DuPont for hosting the Roundtable Event and thanks to all participants for their time and contributions to the discussion. For more information on DuPont visit: www.construction.tyvek.co.uk
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