Interior view of glass box extension with slim aluminium frame and rooflight.

There’s something almost magical about watching sunlight pour into a space from every angle. No walls blocking the view. No heavy frames interrupting the sight lines. Just pure, unobstructed glass creating a room that feels like it’s floating between indoors and out.

Structural glass additions have moved beyond the realm of high-end architectural magazines and into real homes across the UK. But with several options available, how do you choose the right one for your space? Let’s break down the three most popular choices and what makes each one special.

Glass Box Extensions: The Show-Stopper

Interior view of projecting glass box window with slim aluminium frame.

Imagine adding an entire room to your home where the walls, roof, and sometimes even the floor are made almost entirely of glass. That’s a glass box extension. These frameless structures use minimal structural supports, creating an experience that’s closer to being outside than in.

Where they work best: Kitchen extensions are the natural home for glass boxes. Ideal for dining areas where you want that indoor-outdoor entertaining experience, or as garden rooms that let you enjoy your landscaping year-round.

Why it’s worth it:

Ultimate wow factor that stops guests in their tracks
Floods previously dark spaces with natural light from every angle
Thermally efficient systems mean year-round comfort, even in winter
Adds significant value to your property
Creates genuine indoor-outdoor living experience
Unobstructed views of your garden from multiple sides

Roof Lanterns: Bringing the Sky Inside

Kitchen extension with aluminium roof lantern and slimline framing.

A roof lantern sits on top of an existing flat roof or extension, essentially creating a raised glass structure that draws light down into the room below. Think of it as a sophisticated skylight with architectural presence.

Where they work best: Perfect for single-story extensions where you want to maximize ceiling height and create that cathedral-like feeling. Kitchen-diners benefit because they bring light to the centre of the room where wall windows can’t reach. They also work brilliantly above staircases or in hallway extensions.

Why it’s worth it:

Works with existing walls, reducing structural complexity
Creates dramatic vertical space and ceiling height
Natural light reaches the centre of rooms where windows can’t
Maintains privacy while still flooding space with daylight
Adds architectural character to standard flat-roof extensions
Statement piece that elevates your entire room

Flat Roof Windows: The Smart Compromise

The flat roof windows are essentially skylights designed specifically for flat roofs, sitting flush or slightly raised. They’re simpler than roof lanterns but far more sophisticated than the old-fashioned skylights your parents might have had.

Where they work best: Loft conversions are the obvious choice, but they’re also excellent for bathrooms where you want natural light without sacrificing wall space or privacy. Single-story rear extensions, utility rooms, and home offices benefit enormously from the additional daylight without the expense of a full lantern.

Why it’s worth it:

Most budget-friendly option with real impact
Available with opening versions for fresh air and ventilation
Some models include integrated blinds for convenience
Perfect for bathrooms where privacy matters but light is needed
Natural light plus stargazing potential
No major structural changes required to existing spaces

Making Your Choice

The “invisible” room addition isn’t just about glass and engineering. It’s about changing how you experience your home every single day. Whether that’s worth every penny depends on whether you value living in light.