April 23, 2023

A Guide to Natural Light in Architectural Design  

Written by Rebecca Clayton

Ensuring plenty of natural light is key in the design of any home, whether this is incorporated from the start in a ground-up new build project, or in an extension added down the line. We’ve seen increasing amounts of research showing the positive impact of light on health, as well as home trends zoning in on biophilic design and indoor-outdoor living.

The key to achieving this lies in the specification of high performance, minimally framed glazing. High-end glass solutions maximise the amount of daylight entering each living space while ensuring no compromises are made on other aspects of the build.

With such a huge range of bespoke and technical glass available, homeowners and designers are able to enjoy a huge degree of flexibility – from oversized frameless facades to industrial-style steel room partitions. This guide will introduce the fundamental glazing solutions that can be utilised to create a light-filled home.


Pros and Cons of Highly Glazed Designs

Fully glazed designs make for a stunning building, whether this be a luxury new build home or modern high-rise offices. Frameless picture windows and floor-to-ceiling structural glass facades forge a strong connection between the build, its occupants, and the surrounding environment, taking advantage of the views as well as capturing plenty of natural light. Glass design is also important in complementing the interior aesthetic of the home, with minimal glazing offering a blank canvas for modern interior design to draw from.

The impact of natural light itself has been proven with many studies over the years, from enhanced productivity levels to increased general wellbeing. It is argued that humans are not designed to spend such long amounts of time indoors as is required by modern lifestyles, with artificial lighting negatively impacting our circadian rhythm. Using large elevations of minimally framed glazing in each living space is, therefore, key to promoting physical and mental wellness.



Taking advantage of natural light can also result in substantial energy savings, by reducing the need for electric lighting in residential dwellings. Electric lighting makes up over a quarter of UK energy usage each year, highlighting a huge area for potential savings in both energy output as well as bills. However, excessive daylight without proper planning can also trigger the opposite effect, with excessive solar gain that requires air conditioning during hotter months. Solar glare can also result in significant discomfort, with homeowners potentially turning to draw shades and curtains, again resulting in the need for electric light.

However, the good news is that these are all issues that can be controlled through modern glazing technology, such as solar control glass that reduces heat gain into a room and heated glass that keeps spaces warm during the cooler months.


How to Incorporate Natural Light into Any Design

Before we get into specific design ideas, it is important to be aware of the different glazing solutions available, as well as key factors to consider when deciding whether to specify a particular product. This section of the guide will cover:


    • Achieving bespoke designs with structural glazing
    • Window designs
    • Door designs
    • Internal Glazing
    • Roof glazing options
    • Technical glazing solutions

Bespoke Structural Glazing Design 

Structural glass is the bread and butter of luxury residential glazing design. Slim structural silicone joints between glass panes allow for the creation of huge frameless facades with almost limitless sizes and shapes. This allows us to design rooms flooded with natural light, by installing entire walls, roofs, floors and oversized windows out of glass.

What to look out forA key aspect of any glazing is its thermal performance, and structural glass is no different. Look out for thermally broken systems that provide significantly improved Uw values. The Invisio structural glass from IQ is the first system on the market to be fully thermally broken, a key factor that allows designers to incorporate oversized glazed elevations whilst still complying with thermal performance values required by building regs. Invisio+, the latest update to the minimal system, introduces a triple glazed option for further enhanced performance across large glass facades.

Structural glazing can be used to create a number of designs to promote the influx of natural light, including:



Glass WallsFloor to ceiling glass is an impressive way to take in the views and open up the feel of any room. A modern alternative to curtain walling, long elevations of frameless glass can be created with minimal silicone joints between each pane. Read our guide covering different design options for glass walls here.


Floating WindowsThe bespoke nature of structural glazing means that opening elements can be integrated within a larger fixed glass elevation for a truly unique floating invisible window design. Read more on our invisible floating windows.



Glass Links – Frameless glazed links act as a minimal bridge between contrasting elements within the home. This makes them perfect for connecting modern extensions to historic or listed buildings, or for adding a sheltered walkway between the main home and an external outbuilding, such as this home office in the garden. More information on glass links here.


Refurb & Restore Features Mount House in Issue 25


Glass Balustradesstructural glass balustrades have diverse uses. They are most traditionally used for creating glazed balconies and Juliette balcony configurations, as their frameless designs allow light to flow uninterrupted into the connected internal space. They can even be integrated with walk-on glass floors for a floating balcony aesthetic, as was done for this project in London. The balustrade system from IQ Glass is highly flexible and can also be used to great effect internally, to line stairways and landing areas.

Glass Roofs – Structural glass can be utilised to create a fully glazed roof for a truly light-filled space. For a minimal design, low iron glass beams can be used as a transparent supporting structure, with fixings concealed within the building finishes for a minimal design. Alternatively, statement steel T sections can suit a more traditional, industrial-style interior design.

Glass Box Extensions – glazed conservatory extensions bring each of these frameless structural glass elements together in the form of a highly modern, light-filled extended living space. IQ Glass has worked on many stunning home extensions that opted for rear glass boxes, as well as luxury new build homes that incorporate them as part of the wider glazing package. An example of this can be seen in the Dynargh new build home in Cornwall, where sliding doors connect a cosy sofa space with the coastal views beyond. You can read our full guide to glass box extension design, or find our beginner’s guide to glass box extensions here.

Specifying Structural Glass - Due to the bespoke nature of structural glazing, there are multiple technical elements that need to be given careful consideration throughout the design and installation. This includes the glazing specification, performance and calculating loading requirements unique to the project. With this in mind, we highly recommend using a glazier with an expert in-house team that will carefully detail each individual glass junction and fixture to ensure a successful project. Our guide to specifying structural glass gives more information on this.


Window Specification for Light-filled Homes

When choosing window designs for a project, natural light can be maximised by opting for slim framed or frameless systems, as well as by increasing the size of the glazing where possible. Combining architectural glazing and modern casement profiles creates a balance of fixed and opening windows that minimise visible sightlines across the project.


Fixed Window Glazing

Fixed picture windows can be specified in a fully frameless design for a beautifully minimal aesthetic. Using structural glass, instead of outdated chunky UVPc, allows for highly bespoke designs in dramatic oversized configurations, while hiding the fixings within the building finishes for an all-glass design.

With architectural glass, you can create impressive floor-to-ceiling windows, up-and-over eaves window designs and frameless 3D box windows for a cosy nook with a view. The bespoke nature of this type of glazing means limitless window designs can be created to suit any home while opting for a thermally broken system allows each design to achieve high thermal performance values.


Opening Windows

For opening casement windows, aluminium systems provide elegantly slim and modern frames for a beautiful influx of light into the home. The visible profiles can be powder coated in any RAL colour for seamless cohesion with the overall project aesthetic. Aluminium window systems, like the high-performance Sieger range, can be specified with very minimal frames, or with glazing bars for a timeless steel look.

For a truly luxurious and artisan finish, solid steel casement windows can be specified. Slim glazing bars in bespoke configurations can be added to complement minimal, art-deco interior designs, while still allowing plenty of light to pass through the glazing. Just make sure that the steel system you specify is thermally broken, in order to ensure the living spaces are at a comfortable temperature as well as brightly lit.

One final thing to consider is the opening type that you choose, which will impact the thickness of the frames. Tilt and turn windows tend to have the largest profiles, while standard hinge casements can be much slimmer. For a highly unique design, the classic sliding door design can be adapted as a window, which provides an opening solution with ultra-slim sightlines that maximise the size of the glazed panels. The sliding door systems from IQ can be designed as a modern window with 20mm vertical sightlines while concealing the outer frame within the walls for the most minimal design.

Read more here on weighing up the best window system for your project.


Choosing Glass Door Designs

When specifying doors for your project, most products fall into three main categories: sliders, bifolds and casement/hinge doors. Each of these configurations comes with its own advantages and disadvantages depending on the desired design and aesthetic.


large format sliding glass doors with triple glazing to a sustainable house build shown at night


Sliding Doors

Slim sliding glass doors are more popular than ever before and with good reason. Sliding systems allow for ultra-slim sightlines that maximise the area of transparent glazing, creating a seamless connection between the indoor and outdoor spaces while allowing plenty of uninterrupted light.

In addition to having very slim vertical profiles, some systems allow for concealing the outer frames within the building’s finishes, for a truly minimal aesthetic that maximises the influx of light. The slim sliding doors from IQ have sightlines from just 19mm with the glass structurally bonded to the frame, for a highly secure and watertight solution.

The main downside to sliding doors is that they don’t allow for a fully open aperture when open, as there will usually always be at least one fixed pane, which the other units slide behind. This issue can be mitigated by opting for a pocket door configuration, where the sliding door disappears into a concealed wall cavity. However, this relies on having the available space to create the pocket.

Read more on technical questions to ask when specifying sliding doors here.

Bifold Doors

The main advantage of bifolding doors over sliding systems is that they allow for a larger aperture that can be fully opened up. With a bifolding system, 90% of the opening can be revealed thanks to the ability to stack the doors neatly together at one side, allowing for a more accentuated connection between the indoor and outdoor living spaces. This is particularly useful for rear renovations and properties that have limited available space, as it allows the homeowner to use space more efficiently where a fully open-air connection is desired.

Bifolds are extremely flexible in terms of possible configurations and sizes. Up to 7 panes of glass can be installed to open in one direction, which only uses one base track – this offers an advantage over sliding doors, which can end up with multiple tracks intruding into the floor space of a room if many sliding panes are desired. Like sliders, bifolds can be configured as corner-opening for a dramatic floating corner aesthetic that really maximises the sense of space and light during the warmer months.

The visible profiles in a bifold system are wider than those of sliding doors, due to incorporating a hinge in the joint between each pane. However, the Sieger Lux by IQ offers the slimmest bifolding sightlines on the market, at just 30mm with a full thermal break, in comparison to other products on the market which typically range from 90-185mm. The Sieger range also offers the tallest bifolds on the market, allowing us to provide modern, high-performance solutions that meet the individual requirements of each project we work on.

You can read more information on specifying bifolds here, or visit the Sieger blog for guidance on other related topics, such as comparing aluminium vs steel vs timber bifolding doors.

Casement Doors

Highly minimal glazed single doors can also be used to great effect for a light-filled new build or extension design. Opting for a pivoting door allows for a very slim frame design, giving the illusion of a full-height window when closed, but with a smooth and easy opening function.

Pivot doors and sliding doors can be specified in dramatic oversized configurations that allow the minimal glazing to take centre stage. This works well for renovations and new builds alike, where a double-height living space can be created as the main hub or centrepiece of the design. Hollycroft Avenue is a great example of this, where a double-height pivot door was specified alongside oversized sliding doors.

Frame Materials

Aluminium profiles provide a modern and highly flexible base frame material, with many finishing options including RAL powder coatings and a timber aesthetic. For an industrial-style aesthetic, slim steel systems can be chosen for an artisan, hand-crafted feel.

The Mondrian and MHB steel glazed systems from IQ are both fully thermally broken, providing a high-performance solution for external use. Steel doors can also be specified with a range of finishes, including galvanised, Corten and architectural bronze. It is worth noting, however, that aluminium systems are recommended for marine or other harsh environments, as they are less easily corroded by abrasive chemicals in the atmosphere.

For an art deco appearance without the cost of steel, the Sieger Legacy range provides steel-look aluminium casement and bifolding doors with applied glazing bars in bespoke configurations. This is a great in-between option that achieves a very similar feel and looks to the steel alternative.

Read more on weighing up different types of patio doors here.


Using Internal Glazing to Create Light-filled Spaces

Dim and dingy internal living spaces are a common problem that can be tackled with a home renovation. Even large windows at the end of long, narrow spaces may not provide enough light to permeate deep into the room. Using frameless glass doors and room partitions is a fantastic way to encourage the seamless flow of natural light throughout the entire series of living spaces.



When looking at internal door design, there are many options and configurations available, from internal sliding glass doors to pivoting or even bifolding configurations that fold away to maximise the amount of space available. Homeowners can also choose between frameless designs or loft-style aesthetics with the inclusion of glazing bars. Any number of bespoke designs can be created, depending on how the internal glazing will fit into the interior design scheme of the house.

Glazing can also be used to create other internal elements within the home. Designing a bespoke glass staircase is one way of opening up a central hallway space. Alternately, frameless glass balustrades can be used to create mezzanines and landing areas with a bright, open-plan feel.

Another option is to create internal wells of light that connect the deeper living spaces with the outdoor environment. One way of doing this is to design an internal glazed courtyard, connected to the living rooms via sliding glass doors and frameless walls. Another method is to design an atrium, traditionally defined as a small open-air space integrated within the internal room structure of a house. Field House used this technique to allow natural light to permeate the basement-level recreational family room, while KO House designed an internal garden space that conducts light and fresh air through both storeys of the modern house.


Create Ceilings of Light with Roof Glazing

No matter what type of project you’re working with, integrating some form of roof glazing can go a long way to creating a beautifully lit living space. We’ve already touched on using structural glass to create stunning frameless glass roof designs, so let’s look at the other key area within this section: rooflights. The range of rooflights on the market is extensive, from standard fixed rooflights in flush or lantern designs to sliding and venting configurations.



Fixed rooflights are great for achieving highly minimal designs and brightening up a living space. Fixed designs can be configured to appear completely frameless when viewed from the inside, for an elegant pocket of light. The Invisio system from IQ can be used to create rooflights of many sizes and shapes, allowing for very large and unique designs.

For the added option of adjustable ventilation, opening rooflights should be considered. Sliding designs add a touch of luxury – when opened, they create a fully frameless opening that gives a sense of al-fresco dining to a kitchen during the warmer months. The MARS is an advanced sliding system that can be configured in almost limitless designs, with the potential to create huge sliding ceilings with integrated weather sensors and smart technology options. It can also be used for roof access, for projects that want to create an opulent terrace space to enjoy. Read our FAQ on the sliding rooflight here.

Venting designs are a great in-between option, allowing plenty of fresh air to enter the room while not taking up as much space as a sliding system. The ARES is highly bespoke, combining minimal concealed motors and slim frames with limitless potential shapes, from hexagonal configurations to large circular designs. If opting for a corner-less look, the ARES can be configured to lift the entire rooflight upwards for ventilation, rather than requiring a hinge.

Whilst these slim systems are great for a minimal, non-intrusive design, box and lantern designs can also be specified to add a sense of height and space to a room. The bespoke range of roof glazing from IQ can even adapt these designs to create sliding lanterns or boxes.

When specifying any kind of roof glazing, make sure that the system is thermally broken and ideally structurally bonded with heavy-duty weather seals to minimise condensation forming on the inner face. It is also important to check the system uses toughened glass with a laminated interlayer, to ensure that the glass will be held in place in the event of a breakage.

Read more on strategic roof glazing designs to maximise light in the home.


Maximising Natural Light through the Strategic Use of Technical Glazing

Historically, the use of plain float glass and non-thermally broken frames has led to a multitude of overheating conservatories and windows with poor thermal performance. However, the specification and glazing technology on the market has greatly evolved, with increasingly high-performing solutions becoming available that allow the homeowner to create fully glazed designs without making sacrifices in heating costs and carbon emissions.


Solar Control

One way to reduce the risk of overheating in a glazed space is by incorporating solar control glass technology. This near-transparent glass coating reduces the short-wave solar radiation that enters a space, leading to reduced heat levels inside the room and reducing the need for air conditioning during the hotter months. Read this guide for more technical advice on solar control options.


Reducing Heat Loss

Conversely, glazing specification can also reduce heating bills during colder weather. Opting for high specification glazing design, such as thermally broken frames and triple glazed units, is one way to improve the thermal performance of the glass and reduce heat loss. Low-E coatings can also be applied to the inner pane to reduce the amount of heat the glass units absorb, by reflecting radiant heat back into the internal space rather than letting it escape.

Homeowners can take this one step further by incorporating heated glass into the design, which acts as an invisible radiant heat source that permeates the living space. Electrically heated glass is very energy efficient and can be easily adjusted according to the desired temperature. It can be used as the sole heat source in a room, thus avoiding cluttering the interior design with physical heaters and radiators.


Improving Transparency of Glass Design

Standard float glass has a naturally occurring green tint caused by its iron oxide content, an impurity found in all glazing. This tint becomes increasingly apparent in thicker structures, as well as exposed edges found in balustrades and glass beams. Low iron glass is a specialist solution that drastically reduces the iron content of the glazing, resulting in improved transparency and light transmission, ideal for use in highly glazed projects. For more information on specifying low iron glass across different glazing applications, check out this guide.


Fire-rated Glazing

In order to meet fire regulations in a building design, it may be necessary to incorporate fire-rated doors. Extensive technical developments have been made in this area over the years, with fully frameless fire rated glass doors now available. This makes these doors ideal for promoting the flow of light through each living space, whilst maintaining a minimal and contemporary design that meets safety regulations.


How to Inject Natural Light into Specific Project Types

We’ve introduced the main ways architectural glazing can be configured to create a modern, light-filled project. Now let’s take a look at some important project types and the kinds of glazing that can be best used to suit each space.


Side Infills and Side Returns

Side infill extensions use minimal structural glazing to expand the usable living area, usually by converting disused alley space to the side of a property. This type of extension is typically used for townhouse extensions, where homes were designed with a narrow strip of land that serves little purpose beyond a storage area for bins or bikes.


Extending the room to include this small space can have a big impact on the sense of space and size. Structural glass roofs or long strip rooflights are a great way to introduce an influx of light into the enlarged room below, with no chunky frames obstructing views or light. Large glass doors can then be incorporated into the rear elevation, with slim framed bifolds or sliding doors working particularly well to create step-free travel between the garden space and internal living space.



Adding a basement is a great way to add extra space when other extension options are limited, but creativity and careful planning is needed to pull off a bright and comfortable space. Basements lend themselves particularly well to roof glazing – particularly walk-on floorlights, which maintain a flush floor-level for the space above the basement while introducing much-needed light into the space. If the basement extends out beyond the living areas above, a full walk-on glass roof can be integrated into the garden design.

Proper use of internal glazing is key for large subterranean spaces. Frameless glass partitions are an excellent way of dividing the space while allowing daylight to flow uninterrupted, while glass balustrades can be used to line the stairs to the upper floors.

If the basement runs out into the garden, a sunken courtyard can be designed to create another medium for light to reach the living space. At the garden height, frameless glass balustrades can line the edges of the courtyard to provide uninterrupted light transmission into the space below, while ultra-slim sliding or pivoting doors can provide a minimal bridge between the basement and the outdoor space. The Gibson Square project did just that.


Loft and Roof Extensions

Loft extensions are a hugely popular way to expand the home without increasing the building’s footprint, and rarely pose an issue when it comes to planning permission. Roof extensions typically benefit from dormer windows, which protrude out of the roof to provide extra space within the sloping ceilings. Sliding glass doors can be integrated instead of windows to provide a balcony area overlooking the garden.

Rooflights are an ideal solution for loft renovations. Opting for a venting or sliding configuration ensures that the space can be well ventilated as well as benefitting from extensive natural light. Concealed electric blinds can be integrated within the minimal design to provide full or partial blackout options if required.

Structural glass can also be used to maximise the influx of light into the loft or attic space. Frameless gable-end windows can be incorporated into the design, replacing solid walls on either end of the room. For a dramatic extension idea, glass box extensions can be built onto the top of buildings to create a dynamic glazed living space that overlooks the skyline. Read the key aspects to consider when planning a loft extension or conversion here.



Adding a luxury garage is a must-have for prime residential property design and poses the perfect opportunity to integrate minimally framed glazing to showcase the car collection. Slim sliding glass doors ensure ultra-minimal sightlines that do not detract from the collection while providing flush thresholds that allow the cars to be smoothly driven in and out of the garage.

Additional technical glazing solutions can also be incorporated to ensure the optimum environment for the cars housed within the structure. The heated glass keeps the room at a comfortable temperature throughout the day and night, while anti-reflective glazing minimises reflections and glare so that the statement feature can be enjoyed from any angle. See more on designing luxury garages here.


New Builds

Of all the project types, new builds are arguably the most flexible in terms of the designs that can be created, particularly when dealing with an uncomplicated plot that has been granted full planning permission. To create a truly luxury home, opt for a full glazing package that combines large elevations of floor-to-ceiling glass walls, frameless internal glazing throughout each living space, sliding rooflights, frameless picture windows and ultra-slim sliding glass doors. For more ideas and information on creating a prime residential project, see our guide on key aspects to consider.

For more inspiration on designing an extension, read our full house extension guide.


10 Examples of Natural Light-Centric Designs

To tie up this guide, we’ve compiled a few projects that really bring together clever glazing design to create modern, comfortable living environments flooded with natural light.


    1. Water End

Frameless glass walls and sliding doors wrap around three sides of this luxury new-build home for an extensive influx of natural light. Internal glass balustrades are used to surround the bespoke staircase, while a stunning home office nestled in the roof is lined with bespoke structural glass walls and a statement glazed gable design.

View the Water End House Case Study


    1. Slot House

Oversized glazing characterises this London townhouse. A bespoke double-height pivot door provides seamless access to the light-filled kitchen space, while an impressive sash window creates a vertically sliding glass façade.

View the Slot House Case Study


    1. Stone Haven

Glass box extensions don’t have to be limited to a simple rear extension. This rural Cornish new build integrated a glass box as part of the glazing package, to provide a cosy nook that overlooks the beautiful coastline.

View the Case Study for the Stone Haven Sustainable New Build House in Cornwall  


    1. The Wall House

Boundary-pushing structural glazing and counterweighted vertical sash doors come together to create this truly unique project. Frameless glass is used to create two swimming pools, while the sliding glass walls surround the terrace seating space.

View the Wall House Open Corner Suspended Glass Bottom Swimming Pool Case Study


    1. Field House

Shaped gable end structural glazing defines this rural English home, with a fully glazed façade that drinks in the views of the countryside, while slim sliding doors provide a seamless connection with the garden.

View the Field House Countryside New Build  Case Study


    1. Sanctuary House

The use of minimal glazing ties into accessibility for this house design. Due to an illness impacting their vision, the homeowners opted for frameless glass walls and balustrades lining the large balcony, which maximise the availability of natural light while a bespoke timber overhang prevents excessive glare.

View the Sanctuary House New Build House with Expansive Views Case Study


    1. Britten Street

Fixed frameless rooflights were used to full effect to create a modern, brightly lit basement space to this extension in Chelsea. The walk-on glass floors provide a minimal and contemporary bridge between each of the lower levels.

View the Britten Street Modern 2 Storey Refurb in Chelsea Case Study 


    1. Yew Tree House

This beautiful listed manor house is complemented by a structural glass box, contrasting modern glazing with the exposed original brick walls for a light, open plan dining space.

View the Yew Tree House Listed Extension Case Study


    1. Leign Farm

This Devonshire farmhouse retains much of the character of the region while using slim framed aluminium systems to provide a contemporary and light-centric focus throughout the home renovation. The minimal profiles of the windows, sliders and bifolds are powder coated in an elegant silver colour that contrasts with the white exterior walls.

View the Leign Farm Glass Box Extension Case Study


    1. Claremont Square

This London project is a great example of a side infill extension, combining a frameless structural glass roof with slim sliding doors for step-free access into the rear garden. To the existing kitchen space, an Oriel box window was installed to provide a comfortable spot to read or take in the view.

View the Claremont Square Structural glass roof and Doors Case Study


Final Thoughts

At IQ we believe light is the ultimate luxury when it comes to any architectural design. We are constantly exploring new ways to push the boundaries in bespoke glazing design and have enjoyed years of experience working on exciting projects across the UK and beyond.

Additional Reading Related to Natural Light:

A Guide to Natural Light in Architectural Design

Using Natural Light to Reduce CO2 Emissions 


For more information on specifying glazing for your project, check out our guide to specifying the full glazing package. Or, get in touch for more information on how we can work with you to bring a stunning, light-filled design to life at hello@iqglassuk.com.