What is a fabric first approach?
The term “fabric first” is commonly used in construction, but what does it mean and why is it the recommended approach for most projects looking to achieve high levels of energy efficiency or low operational carbon emissions?
In this article, we explain:
- What fabric first means
- The benefits of a fabric first approach
- How we can support a fabric first approach
What does fabric first mean?
The term “fabric first” means to optimise the performance of the building envelope (walls, floors, roof) before considering reducing the energy consumption of heating and cooling or using renewable technologies such as solar PV. In practice, a fabric first approach typically focuses on:
- achieving excellent thermal performance (U-value) in floor, wall and roof constructions and for windows and doors;
- limiting heat losses as a result of thermal bridging;
- reaching a set level of air-leakage depending on whether the building is naturally or artificially ventilated; and
- optimising solar gains.
A fabric first approach can be adopted both for new builds and as part of planned energy retrofit works on existing buildings. It is important to note that 'fabric first' doesn't mean 'fabric only'. Decarbonised heating, improved energy efficiency of building services and use of energy generation/renewables are also all important. However, fabric first does mean reducing energy demands as the first priority, or alongside those other considerations, to reduce demands on building services and on the energy grid.
What are the benefits of a fabric first approach?
The core benefit of a fabric first approach is that it can reduce the overall energy demand and operational carbon emissions from a building across its lifespan by making the internal spaces easier to keep at a consistently comfortable temperature, lowering the demand on heating and cooling systems. Unlike renewable or heating technologies which will require regular servicingand have a limited life expectancy, properly installed insulation should continue to provide energy savings across the building’s lifespan with no maintenance.
This has several advantages. By reducing the overall energy demand for a property, it means a greater proportion of the remaining demand can be met with onsite renewable generation such as PV panels. It also means that energy bills for occupants should be notably lower than for a building with worse fabric performance.
At a national level, use of a fabric first approach can also support energy security by limiting the energy demand on the national grid. This is especially important as heating systems are transferred from traditional fossil fuel systems to low carbon technologies such as heat pumps which draw from the grid.
In addition, a well-designed fabric first approach can also help to create more comfortable environments for occupants, allowing more consistent internal temperature which can be easily controlled through properly designed ventilation and heating systems.
How can Kingspan products support a fabric first approach?
We have developed an extensive range of insulation products to allow project teams to achieve ambitious U-values with slim constructions in virtually any application. Our product ranges cover both standard applications and potential problem areas to ensure an effective solution.
Kingspan AlphaCore products combine a thermal conductivity of just 0.020 W/mK with a Euroclass rating of A2-s1,d0. This allows them to provide a slimmer alternative to conventional rainscreen insulation where a Euroclass rating of at least A2-s1,d0 is required. This can include a range of problem applications such as where a cladding system is being installed on a wall with a close boundary to another building or cladding retrofit work. It is also suitable for soffit applications where a rating of at least B-s3,d2 is needed.
Our OPTIM-R range of vacuum insulation panels (VIPs) provide a thermal conductivity of just 0.007 W/mK, far lower than conventional alternatives. These systems are designed to allow project teams to tackle areas which previously may have gone uninsulated. These include retrofitting existing solid floors, where the insulation has the be fitted above the existing slab. In this application, the OPTIM-R Flooring System can help to minimise any loss of floor to ceiling height whilst effectively improving the U-value of the construction. Similarly, the OPTIM-R Roofing System can provide and option for areas such as roof terraces, helping to ensure an even transition between internal and external floor levels.
Our Kooltherm range of boards achieve thermal conductivities as low as 0.019 W/mK. This allows them to provide the thinnest commonly used solution for a range of applications including cavity and timber framed walls, solid and suspended floors, internal and external walls and pitched roofs.
Our Therma range boards have a thermal conductivity of between 0.022 and 0.027 W/mK, providing a practical option for many applications. The boards are commonly available from many builders ’merchants. Alongside a range of slim options for flat roofs, we also offer Thermataper systems which can provide both insulation and drainage on flat roofs. These tapered systems are available with a supporting tapered roofing service where our experienced team will create a system design and layout which is optimised for the project.
Kingspan GreenGuard boards have a thermal conductivity of between 0.033 W/mK and 0.036 W/mK . They provide excellent compressive strength and are resistant to moisture ingress. This makes them well suited to applications where they may have to handle significant compressive forces (such as floors within car parks or commercial spaces) or where they may be exposed to moisture (such as inverted roofs or on the external face of basement walls.
Kingspan K-Roc products are rock mineral fibre slabs with a Euroclass A1 rating and thermal conductivities between 0.034 W/mK and 0.036 W/mK. This makes them suitable for rainscreen and framing applications where this level of reaction to fire performance is required.
We have also developed the OPTIM-R E Inverted Roofing System which features encapsulated VIPs with a design thermal conductivity as low as 0.009 W/mK. The coating provides increased robustness and can allow project teams to reach low U-values on inverted roof with slimmer constructions than would be possible for conventional applications.
Offsite solutions
Kingspan TEK systems embrace the power of offsite construction. They are formed from structural insulated panels (SIPs) featuring a rigid insulation core which is autohesively bonded between two faces of OSB/3 board.
The panels provide a high level of thermal performance ‘out of the box’ which can be easily raised further with additional insulation. They also feature a proprietary jointing system which helps to ensure excellent insulation continuity and, in combination with the OSB/3 facing, can help to achieve very low levels of air leakage.
The TEK panels are designed and machine cut to each project’s specifications by our network of TEK Delivery Partners at specialist facilities. This includes creating accurately-sized openings for windows and doors. Once on-site, the panels can be rapidly erected and once windows and doors are fitted and a breather membrane is applied, the shell is weatherproof. This allows internal trades to start work at an earlier stage than is possible with other build approaches.
What technical support can Kingspan provide to support a fabric first approach?
We also offer a wide range of technical support services to help project teams deliver excellent fabric performance both on paper and in practice.
Our U-value calculator provides a simple go-to solution for cases where you need to quickly check the thickness of insulation needed for an application. The tool covers a wide range of applications and products and can be easily adjusted for your project needs. For more complex projects, our technical service department can also produce specific U-value calculations along with supporting condensation risk analyses.
Find out more about our U-value calculation services
To support best practice on-site, we can provide dedicated product awareness talks from our experienced site technicians. These sessions cover all aspects of working with our latest product ranges including handling, storage and installation and can be tailored to your needs. Our technicians can also carry out reviews of insulation measures already installed on-site and provide feedback reports to support best practice.
We also offer a wide range of education materials including knowledge articles and in-person or remote CPDs covering aspects such as the latest Building Regulations and specific applications such as flat roofs.
