Kawneer UK - What is Curtain Walling?
With its unique blend of aesthetic and functional advantages, a curtain wall facade is a key element in modern building design. But what is curtain walling and how has it attained its worldwide popularity on the widest possible range of projects across all sectors?
This guide will give you an overview of the definition of curtain walling, its variations, benefits and other considerations, helping you to choose the right option for your next project.
What is Curtain Walling?
A curtain wall is a lightweight, non-structural exterior wall system, typically made from glass, aluminium and a range of other materials.
Its primary function is to protect a structure from external elements, simultaneously optimising aesthetics and visual appeal.
Curtain wall facades are not load-bearing and are secured to the building’s exterior structure, providing building envelope enclosure.
Because they are designed to span multiple floors, curtain walls will not only support their own weight but also accommodate building movement, due to factors such as thermal expansion and contraction, dead loads, live loads, wind and other imposed loads.
A curtain wall system efficiently manages weather using either a zone or mullion drainage system.
Zone drained: Each panel is individually pressure equalised and drained via its transom, enabling the curtain wall to quickly react to fluctuating wind pressure.
Mullion drained: Suitable for slope glazing, mullion (or point) drainage systems feature overlapping joints.
Types of Curtain Wall Systems
There are a range of system options, depending on design, construction and installation considerations.
Stick-Built Curtain Wall System (Standard)
Pros
• On-site assembly and easily adjustable during installation.
• Customisable and adaptable for a range of architectural designs.
• A vast range of shapes, sizes, sightlines, infills and additional design elements, including fins.
• Cost-effective.
Cons
• Site assembly can lead to longer installation.
• Poor weather can slow site progress.
• Tight quality controls necessary throughout the assembly process.
Unitised Curtain Wall System
Pros
• Factory prefabricated, including glazing, ready for on-site installation.
• Consistent quality of the facade due to factory quality controls.
• An ideal choice for high rise buildings.
• Accommodates increased building movement and heavier infills.
Cons
• Higher cost than site-assembled stick-built systems.
• Specific logistical challenges with transport and installation.
• Care required to precisely align units and interface with other building features.
Structural Silicone Glazed Curtain Wall System
Pros
• Seamless and uninterrupted panes of glass.
• Optimal aesthetics.
• Thermally efficient.
Cons
• Limited vent options.
• Lower building movement tolerances.
• High cost.
Concealed Vent Curtain Wall System
Pros
• No visible framing.
• Allow for natural ventilation, whilst maintaining aesthetics.
• Motorised or manual operation.
Cons
• High cost.
• Requires precise engineering and installation.
• Demands a stringent maintenance schedule.
Fire Resistant Curtain Wall System
The pros and cons of fire resistant façades are determined by the specific application demands. These systems provide increased safety and compliance with regulations, designed to slow the spread of fire. They are also able to incorporate automatic smoke vents and panic opening doors to assist with the safe evacuation of occupants.
Blast Enhanced Curtain Wall System
A blast enhanced system mitigates blast loads created by accidental or intentional explosions. It is designed to minimise structural damage to the building, providing a ‘shield’ in contrast to an ‘envelope’. Blast mitigated curtain walls are often specified for military installations and high-risk public use buildings, including stadiums, event venues and hotels.
Key Benefits of Curtain Walls
Aesthetics and Design Flexibility
Some of the world’s most architecturally striking buildings use curtain walling. It’s hugely popular with designers, due to its ability to provide an attractive seamless façade and be configured in unusual shapes, including curves.
Energy Efficiency
Curtain walls offer vast potential for energy efficiency, facilitating the use of high performance low-emissivity glazing (Low-E), reducing heat loss in winter and heat gain in summer. Advanced thermal break technologies and high-performance sealants, all contribute to reducing energy costs, usage and lowering U values.
Weather Protection
A curtain wall forms an exceptionally capable barrier against wind, rain and temperature extremes. It also offers highly effective rainwater drainage with no ingress to the building.
Structural Advantages
Although they are not load bearing, curtain walls enhance a building’s resistance to the elements, ability to cope with various loads and thermal expansion and contraction. Recent market-leading Kawneer expansion joint innovations have focused on dealing with more extreme levels of building movement (+/- 15mm). Find out more here.
Curtain walling additionally affords a lighter structure than many other facade options, making it especially appropriate for high-rise buildings.
Natural Lighting
The health, well-being and energy saving advantages of high levels of natural lighting are now widely recognised in building design. Curtain walling is arguably the most practical, cost-effective and attractive way of achieving a successful daylighting strategy.
Sustainability
Aluminium’s infinite recyclability gives it many advantages compared to alternative materials. Our Iow carbon billet includes 75% recycled material and features less than 3.0kg of C02 per kilogram of aluminium. Our billets are sourced locally, to help minimise the environmental impact of our logistics, handling and transportation operations. Read more about Kawneer’s BALANCE comprehensive approach to sustainable methods and practices.
Your Next Façade Project
Now you know what a curtain wall is, the different types of systems available, key benefits and considerations, you can better weigh up what solution will be perfect for your project. Kawneer’s Architectural Advisor Team are available to support you.