Let the Light In: Interior Design That Starts with Daylight

At Square One Architects, we believe that great interior design begins with light. Not just artificial lighting plans—but the nuanced choreography of daylight as it moves through space, interacts with surfaces, and reveals the texture and tone of materials throughout the day.

Whether we’re working on a home refurbishment in Hampton or reimagining a flat in South West London, our interiors are shaped by how light behaves. We consider the orientation of each room, the reflectivity of finishes, and the tactile qualities of timber, stone, and fabric. The result? Spaces that feel calm, coherent, and deeply personal.

Why Daylight Matters

Daylight isn’t just a source of illumination—it’s a design material in its own right. It affects mood, energy, and spatial perception. In our projects, we use daylight to:

• Highlight architectural features

• Enhance the grain and depth of natural materials

• Create rhythm and variation throughout the day

From skylit kitchens in Teddington to layered living rooms in Thames Ditton, our interiors are designed to evolve with the sun.

Interior Design That Responds to You

Every client is different. That’s why our interior design services in Hampton begin with listening. We want to understand how you live, what you value, and how your space can support and inspire you. We tailor every detail—from furniture layouts to finish selections—with clarity and care.

Ready to Begin?

If you're planning a refurbishment in Hampton or looking for thoughtful interior design in South West London, we’d love to help.
Contact us to start your interior journey.

Improving Daylight, Space and Living for a Terraced Home in Teddington

We are sharing an update on our latest project in Teddington—a ground floor rear extension to a terraced house. This project shows how architectural changes can improve everyday living while remaining considerate of neighbours.

Project Background

The property has a non-original, partial width ground floor rear extension used as the kitchen. Our client wants to replace this with a new, full width rear extension. The aim is to create an open plan space for the kitchen, living and dining areas, making the main part of the home more practical and inviting.

Design Approach

Understanding the limits of a terraced property, especially regarding light and the relationship with neighbouring homes, guided our design. The client’s brief put focus on daylight, asking for interiors with more natural light.

Daylight Optimisation

To address this, we included a glass roof on one side of the extension, sloping down to 2.2 metres. This allows light to reach deep into the new living areas while reducing the impact on adjacent properties.

We also carried out daylight simulations, analysing how sunlight moves through the space during the day. These studies informed our artificial lighting plan, making sure the open plan kitchen, living and dining areas stay well-lit at any time, in any weather.

Modern Aesthetics and Connection to the Garden

The rear elevation will have “Crittal style” French doors. These create a connection to the garden and bring daylight into the interior. The industrial look of the doors fits with the new extension and respects the house’s character.

Sensitivity to Neighbours

We have considered the effect on neighbouring homes. By limiting the glass roof height to 2.2m on one side and looking at the overall size, we have reduced potential loss of light or privacy for neighbours.

Looking Ahead

With detail design under way, we look forward to seeing this project built. We think it will show how careful design can improve living in older terraced homes.

Stay tuned for progress updates, and contact us if you are considering a similar project in Teddington or elsewhere.

Luminance prediction on March 21st at 12.00

Luminance prediction on June 21st at 12.00

Luminance prediction on September 21st at 12.00

Rear extension in Epsom completed

Today, we visited a completed rear extension project for a 3-bedroom house in Epsom.

The property included both a roof extension and an original outbuilding on the ground floor, shared with the neighbouring property.

The client aimed to extend the property towards the rear, incorporating a side return that would extend 7m deep, all while preserving a side alleyway.

The new extension features a kitchen seamlessly integrated into an open-plan dining area.

Facing northeast, the rear of the property required careful planning to maximize daylight. Therefore, selecting the right size and placement of doors, windows, and rooflights was crucial.

To comply with planning advice, we reduced the eaves height of the rear extension towards the detached neighbour and designed a pitched roof for the side return section, with an external eaves height of approximately 2.2m. This design element not only became a distinctive feature of the space but also allowed the installation of wide roof windows, which flood the open-plan area with natural light.

We and the clients are delighted with the final result, which beautifully enhances the home's functionality and aesthetic appeal.

Daylight and luminance analysis for an extension in Kingston

We regularly use analysis tools to predict the amount of daylight received in a space as a function of the openings size, location and moment of the year. In this view we are showing the predicted Luminance on the 21st of March at 12.00 for our new ground floor extension in Kingston.

Daylight analysis tools offer to foresee the exact amount of daylight received by a determined space in several moments of the year. These tools are always very helpful in general, but they play a crucial role in our designs. By scrolling through our project images it is easy to see that daylight intake is a common thread, we are convinced that daylight within a household plays an huge factor in the health and well being of its inhabitants and we feel a duty as Architect to try and optimize this factor in all our projects.

In the case of this project for a rear extension in Kingston, we analysed the daylight intake with a configuration of a sliding door at the right, a generous window at the left and three skylights placed in the middle of the rear extension’s ceiling. With this type of diagram, it is very easy to see that the daylight will be very evenly distributed throughout the floor plan without being overwhelming (refer to the area in green).

Lighting design is a complex discipline, but we try to explain these metrics and parameters to the clients in a very straightforward way so they can understand the rational behind the dimension of the openings in their extensions.

These tools have become an essential part of our work at any stages of the design, especially at preliminary stages prior to submitting a planning application. We look forward to seeing this project finished and show this point with the final pictures.

Work in progress: Daylight analysis for one of our projects in Hampton

We usually determine the final dimension of doors and skylights using daylight analysis tools. These tools play a crucial role in our design process, allowing us to carefully assess and optimize the luminance levels on specific dates. For one of our ongoing projects in Hampton, we recently conducted a thorough analysis and the images below refer to a daylight simulation on March 21st at 12.00.

When it comes to predicting daylight levels, at Square One Architects, we rely on two key metrics: daylight factor and luminance. These metrics provide us with valuable insights, each with its own advantages and limitations. The daylight factor offers a straightforward snapshot of the projected average daylight levels, while luminance provides a more intricate analysis, taking into account factors such as orientation, the day of the year, and the time of day. By carefully cross-referencing these results, we can effectively communicate to our clients the reasons behind our optimized design choices for doors, windows, and skylights, tailored to their unique project requirements.

This particular project involves both a ground floor extension and a loft extension, posing unique challenges when it comes to daylighting. When it comes to the ground floor extension, it is of utmost importance to consider the predicted level of daylight in relation to the orientation of the building and the size of the glazed surfaces. Thankfully, in this case, the rear extension faces north, granting us the opportunity to incorporate generous glazed surfaces while minimizing the risk of overheating during the warmer summer months.