Pushing the envelope on building envelope construction

From architects to specifiers, installer to contractors, every player in the build chain must do their part in creating thermally efficient buildings, and that starts with the building envelope’s construction, explains Andy Stolworthy, Director of Product and Market Development.

With environmental legislation for building design and construction being updated across the globe, a new wave of architecture is being introduced. Architects and specifiers must find ways they can speed up building timelines, reduce energy usage and enhance a building’s lifespan when designing commercial and residential buildings.

The UK is making substantive improvements to its energy codes in order to reduce energy usage and wastage, seeing the construction industry shift towards bioclimatic architecture. Thermally efficient buildings using a well designed and installed envelope are crucial to this movement.

The building envelope is a protective boundary between the interior and exterior of a building that ‘wraps’ around the walls, floor, roof, windows and doors. This envelope shields the exterior of the building from natural elements, whilst facilitating climate control and protecting the indoor environment

Solutions that envelope energy efficiency

When a building envelope isn’t installed properly or is poorly specified, it will contribute to a substantial amount of energy loss, and one area that should not be neglected is the roof. More than 30% of heat is lost through the roof, and flat roofs particularly are prone to energy loss when a poor design is chosen.

There are two types of flat roof, warm and cold, the difference is the positioning of the insulation layer. In a warm roof the insulation is placed on top of the roof structure and choosing the right fastening solution will minimise the thermal bridging. This bridging is a funnel of unobstructed heat flow, which renders the surrounding layers of thermal insulation useless and ultimately can damage the building’s structure.

To prevent this, it is imperative the correct fastening solutions are used that work with the roofing system. Flat roofing solutions such as the Isotak thermally broken sleeve and fastener from SFS will ensure that the cladding is properly secured, therefore avoiding thermal bridges and decreasing energy loss.

The two-part fastener sits inside a polypropylene or polymide sleeve which penetrates below the surface of the insulation, providing a barrier between the fastener head and the external atmospheric conditions. This improves the whole roof’s thermal efficiency and reduces heat transfer through the building envelope.

The materials of the fixtures and fittings is another overlooked factor that contributes to excessive heat loss. Stainless-steel conducts heat at a slower pace than carbon steel which not only improves the thermal efficiency of the envelope but allows for improved corrosion-resistance, thereby maintaining the integrity of the installation and performance for longer. Installers should only use system approved fasteners and consult with manufacturers to identify the right fastener for the right situation.

Faster fixings that envelope efficiency

The building envelope is made up of a variety of different parts that make up a system – using the correct parts throughout will ensure a smooth building process. When the incorrect components are used, efficiency can go down as the wrong components can lead to unforeseen complications.

In the instance of a rainscreen subframe system, the manufacturer will typically just design solutions to meet mechanical and thermal needs. SFS’s NVELOPE system on the other hand will design everything down to the frame fastener to ensure the façade performs. Here is a perfect example where the right fasteners and fixings are paired with the right brackets and subframe systems and both construction and energy efficiencies increase.

Newer generations of fasteners, fixtures and brackets are being developed to aid a quick and easy installation too. For example, the SXC5 fastener is a self-drilling composite fastener that has been re-engineered to have an optimised tip and thread geometry, allowing installers to drive the fixing into the material they are fixing quicker.

As suppliers and installers enter this new wave of bioclimatic architecture, they must work together to ensure a successful construction of the building envelope. From training to on-site technical assistance and specifying the right components, all parties can secure the future of the building, speed up timelines and enhance its thermal performance.

www.sfsintec.co.uk