As the popularity of glazed curtain walling increases, particularly for large urban buildings, Dan Gleeson of Reynaers UK discusses the benefits of aluminium systems and considers the importance of working with experienced suppliers.
Forming an integral part of a building’s identity and character, facades have the ability to transform how we see architectural spaces. In recent decades, as architectural styles have shifted to reflect modern expectations, glazed curtain walling systems have become increasingly popular – on commercial and residential buildings alike.
Curtain wall is typically a non-load bearing structure and transmits the applied loads arising from the wind, glass and framing (dead load) and occupant load back to the primary or secondary structure. On some projects, other load cases may also need to be considered such as barrier loads, maintenance loads, accidental loading, snow loads, blast or impact.
When it comes to the types of curtain wall used to clad buildings, there are two main types: stick and unitised facades. Enclosing the envelope of the building to protect from the weather, insulate and provide an air seal, these two types of curtain wall can be adapted from their standard design to create bespoke features which are engineered to emphasise geometry or a particular aesthetic appearance. As a result, curtain wall systems equip architects with the freedom to create an aesthetically led façade which meets the specific performance requirements of the building.
Performance
Spanning multiple floors and covering a large surface of the building, curtain wall forms a significant part of the envelope. As such, systems can directly impact cost, design and delivery programme, in addition to key performance considerations – particularly in terms of water tightness and thermal characteristics, daylighting, ventilation regimes and acoustics. Another fundamental part in selecting the correct curtain wall is the accommodation of building movement.
The taller a building gets, the more movement can be expected, creating the potential for a range of building movements such as windsway, inter-storey drift, differential slab deflections, settlement, creep and even seismic loads. Although some types of movement are more typical outside the UK, it is important for every aspect of the building envelope to be designed to accommodate such movements.
Where movement is concerned, Reynaers recommends early engagement with a structural engineer to fully understand which system will be best suited. This allows deeper understanding of the movements and enables the correct façade system to be specified, helping to avoid budget implications, delays and even project re-designs further down the critical path. Failure to allow for building movement can lead to induced stress in the profiles or surrounding components, potentially leading issues around the opening of joints and water ingress.
Aside from building movement, aluminium curtain wall systems can support buildings to excel in other critical aspects. As urban areas become increasingly populated, controlling noise levels within a building increases comfort for occupants. Here, curtain wall systems have a part to play and can reduce noise concerns such as flanking sound transmission, which is particularly relevant for multiple-occupancy buildings. Accommodating the large glass thicknesses and glass weights associated with acoustic glazing, alongside the inclusion of profiles that stop direct transmission, Reynaers curtain wall can directly support acoustic performance.
The test data for our systems speaks for itself, with each different curtain wall type offering varying levels of performance, depending on characteristics like profile design, gaskets and openings. CW 50, for example – the leading curtain wall system from Reynaers – offers all-round performance having passed CWCT Sequence B testing, providing independent accreditation. Different technical variants can also accommodate specific fire resistance requirements where needed.
Elevating aesthetics
While the technical performance of curtain walling is a primary consideration for those specifying systems, there is one clear benefit to including them in a building’s design – aesthetics. As a fast and cost-effective way of introducing large volumes of glazing into a building, these systems hold the potential to define a building’s appearance.
For occupants, the benefits are clear to see. Large and often full height windows flood rooms with natural light, making spaces more comfortable, practical and modern. Alongside the positive impact this can have on wellbeing, curtain wall systems can introduce greater connections between inside and outside spaces and maximise views, further elevating the appeal of buildings for occupants.
From the outside, curtain walling equips buildings with a distinctive appearance which defines their unique character. It can also help them to fit into their environment more easily. By reflecting the architectural styles which sit in a building’s immediate vicinity, architects can ensure a level of consistency and appreciation of location aesthetics, while introducing a new layer of a city’s architectural fabric. To achieve this, it is crucial for architects to specify systems which facilitate creative freedom, without compromising the performance benefits required.
Ensuring correct specification
To unlock the full suite of benefits which are made possible through curtain walling, it is crucial to work closely with suppliers and collaborate with design teams from the very outset of a project. Particularly on large scale projects, such as high-rise buildings where curtain walling is most in demand, this approach ensures success.
It is for this reason that, at Reynaers, we encourage direct collaboration between our partners. Through our Consult programme, our in-house team of specialist consultants, engineers and technicians work closely with architects and building professionals to offer technical assistance. This close collaboration facilitates a deeper understanding of a project’s specific requirements and allows for the correct systems to be specified, including bespoke systems which are tailor-made to meet the specific demands of a project. Complementing this hands-on approach to working with our partners, Reynaers offers a broad selection of profiles and tested systems and has the capability to test systems in-house, ensuring every system performs as required.
By working together with partners throughout the supply chain, architects and building professionals can lean on the expertise of the wider supply chain and bring their visions to life with glazed curtain wall systems, while weaving uncompromising performance and quality into the fabric of their buildings.
For further information, visit www.reynaers.co.uk