Glazing explained: storefront vs curtain wall vs window wall

Glazing jargon can be complicated. Learn the most important differences between a curtain wall, a storefront and a window wall.



One of the complexities of construction and architectural design is the fact that any one component must fulfil multiple functions.

Take the front of a building – any building. Its primary function, of course, is to protect the people inside from wind and rain.

But this is far from its only function. The building exterior should also keep noise to a minimum. It should help manage heat loss and gain, depending on the season. In some contexts, it needs to be fire-resistant, bullet-resistant or bomb-resistant.

This is a complex brief before you get into the question of aesthetics. Whatever the building is used for, appearances matter. Architects, building managers and building occupants all want the front of the building to reflect what's going on inside to some degree. And ideally, it should do this in an aesthetically pleasing way.

Given this functional complexity, it's no surprise there are multiple options for building exteriors. In this article, we explore three of them: storefronts, curtain walls and window walls.

What are the differences – and why does it matter? Let's take a closer look.

What is a glazed storefront?

A glazed storefront is a framed, ground-level glass system. As the name suggests, it's designed for use in retail entrances, lobbies and low-rise commercial buildings.

Storefront frames are overwhelmingly made from aluminium. However, steel and wood options are available.

They're non-load-bearing and typically span a single storey between floor slabs. They support large panes of glass that let shoppers look in and out without having to face the wind, rain or cold.

Glazed storefronts can be stick-built (assembled piece-by-piece on-site) or pre-glazed in factories. They can be framed. They can be frameless for a modern, seamless look. Or they can be modular and self-supporting for flexibility and portability.

The key differences between storefronts and curtain walls are their size and application. Storefronts are small and used in single-storey structures. Curtain walls, by contrast, are tall and span multiple storeys.

What is a curtain wall?

Curtain walls are non-load-bearing and lightweight facades for building exteriors. They often consist of aluminium frames and glass, although here at Wrightstyle, our curtain wall glazing systems are made exclusively from steel and glass.

Curtain walls hang on the outside of a building's structure. Their non-load-bearing nature means they don't support floor or roof loads.

They're large-span, meaning they often go from floor to ceiling. This helps businesses achieve a sleek, seamless, modern aesthetic with no compromise to thermal or weather performance.

Curtain walls are most common in high rises. This is a key difference from storefronts, which tend to cover just one floor. They can be made bullet-resistant, blast-resistant or fire-resistant depending on context.

They can be unitised, meaning they're made from prefabricated panels fully assembled and glazed in the factory and then installed on-site. They can also be supplied as stick systems, meaning they're put together piece by piece in situ.

What is a window wall?

A window wall is a type of exterior building facade. Glass panels are installed slab-to-slab. The panels sit on each floor and span up to the ceiling.

Window walls are best known as a cost-effective alternative to curtain walls. They primarily differ from curtain walls in the way they're installed. Where curtain walls hang outside the slab, window walls sit between the concrete slab edges.

They're typically used as a cheap alternative to curtain walls and can be installed more quickly. They're most commonly used in high-rise residential buildings, allowing for wide views and natural light.

Window walls are also often modular. They can resemble a grid, with vertical and horizontal framing, or use slab edge covers to look closer to a seamless curtain wall.

Another advantage of window walls is that they're easy to repair. Individual panels can be replaced without the whole facade being affected.

They differ from storefronts mostly in terms of where they're installed. Storefront systems are low-rise and most commonly found in ground-floor retail settings. Window walls, by contrast, tend to be used for multi-storey residential and office settings.

Moreover, storefront systems are non-load-bearing and span the ground floor, whereas window walls are stacked slab-to-slab systems that are usually installed from the second floor up.

What glass is used for curtain walls, storefronts and window walls?

In all these applications, the type of glass used is important and contributes to the overall performance of the installation. It can affect everything from thermal performance to safety.

Storefronts typically use toughened glass (also known as "tempered glass") for impact resistance and safety or laminated glass to prevent break-ins.

Curtain walls also use safety glass. This will be toughened, laminated, or toughened and laminated to meet structural, thermal and safety requirements. Specialised glass can be used for bullet resistance, fire resistance and blast resistance.

Window walls use safety glass, too. This will typically be toughened glass for strength and laminated glass for security, often in double- or triple-glazed units.

Toughened and laminated glass are both types of safety glass but differ in manufacturing processes, strength and breakage patterns.

Toughened glass is made by heating a standard sheet of glass at around 650°C (1,200°F). The glass is then rapidly cooled with blasts of cold air. The result is a glass product around five times stronger than standard glass. When it breaks, it shatters into lots of relatively harmless pieces rather than large shards.

Laminated glass, meanwhile, consists of two or more sheets of glass – sometimes toughened – with plastic interlayers in between. The resulting unit is around six times as strong as standard glass. Laminated glass is highly impact-resistant – and when it breaks, it's designed to maintain its structural integrity by remaining in its frame.

Are you looking for high-performance steel curtain wall glazing systems? At Wrightstyle, we provide tested, compliant systems backed with excellent technical support. Get in touch today for expert, step-by-step advice.