Call us anytime on 01243 538999 – David our digital assistant will take a few details so the right specialist can follow up personally.
Price From
£40,000
Build Time
12-16 Weeks
Thermal Rating
A++ Rated
Guarantee
10 Years
From £40,000
What is a Glass Box Extension?
A glass box extension represents the pinnacle of contemporary architectural design. Using structural glazing technology, these minimalist extensions create an almost invisible boundary between your living space and garden.
At Room Outside, we specialise in bespoke glass box extensions featuring floor-to-ceiling glass panels, flat structural glass roofs and large-format sliding or pivot doors. Each installation is precision-engineered to create a seamless indoor-outdoor living experience.
Every glass box extension is precision-engineered with premium structural glazing and the latest thermal technology.
Frameless Structural Glazing
Constructed using structural safety glass with structural glass purlins sealed with structural silicone bonding using unique and specialist techniques.
Floor-to-Ceiling Glass
Full-height glazing maximises views and floods your space with natural light.
Sliding & Pivot Doors
Choose from large-format sliding, pivot or bi-fold doors for dramatic openings.
Walk-On Glass Roofs
Optional glass roofs create stunning visual connections between floors.
Door Options
Door & Opening Options
Choose from a range of premium door systems to complete your glass box extension.
Sliding Glass Doors
Up to 6m opening widthUltra-slim profilesFlush floor tracks
Pivot Doors
Up to 3m heightHidden pivot mechanismDramatic entrance
Common questions about glass box extension costs, planning and installation in the UK.
A glass box extension is a minimalist architectural addition using structural glazing. It creates an almost invisible boundary between your living space and garden, maximising natural light and views.
A frameless glass box extension typically costs from £40,000 to £100,000+ depending on size, glass specification, and complexity. Room Outside offers premium glass extensions from £40,000 fully installed with building control and 10‑year guarantee.
Many glass extensions fall under Permitted Development Rights, but restrictions apply in conservation areas and for listed buildings. Room Outside provides full planning guidance with every project.
Yes. Our glass box extensions feature New Generation Glass technology with advanced thermal breaks and low‑e coatings, achieving A++ energy ratings. They keep you warm in winter and cool in summer.
A typical glass box extension takes 12‑16 weeks from initial consultation to completion, including design, structural engineering, foundations, installation and finishing.
Get Your Free Glass Extension Quote
Book a free home design consultation with our specialist team. We’ll discuss your vision, assess structural requirements and provide a detailed quotation.
Call us anytime on 01243 538999 – David our digital assistant will take a few details so the right specialist can follow up personally.
Frequently Asked Questions
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What are the benefits of glass box extensions?
The benefits of glass box extensions include enhanced natural light, seamless integration with outdoor spaces, and modern aesthetic appeal. They offer year-round comfort with temperature-controlled glass, creating stylish and functional living areas that elevate your home.
How do glass box extensions enhance living spaces?
Glass box extensions enhance living spaces by creating a seamless connection between indoor and outdoor environments, maximizing natural light, and offering modern aesthetic appeal. Their innovative design also allows for temperature control, ensuring comfort year-round.
What design options are available for glass extensions?
The design options available for glass extensions include various styles such as contemporary frameless designs, sliding or bi-fold doors, and custom shapes to suit your space. Each option enhances aesthetics while providing seamless outdoor connections.
How is temperature control achieved in glass structures?
Temperature control in glass structures is achieved through advanced temperature-controlled glass technology, which minimizes heat transfer and enhances insulation, ensuring a comfortable environment year-round. This allows for optimal climate regulation, regardless of external weather conditions.
What materials are used in glass box extensions?
The materials used in glass box extensions primarily include high-quality tempered glass, aluminum or steel frames, and insulated components to ensure durability, energy efficiency, and aesthetic appeal.
Can glass box extensions be customized for my home?
Glass box extensions can be customized to suit your home. We offer a variety of design options and features to create a bespoke solution that complements your existing space and meets your specific needs.
What maintenance is required for glass structures?
The maintenance required for glass structures includes regular cleaning to remove dirt and debris, periodic inspections for any signs of wear or damage, and ensuring proper drainage to prevent water accumulation.
How do I request a quote for a glass extension?
Requesting a quote for a glass extension is simple. You can fill out the contact form on our website or call our team directly to discuss your project details and receive a personalized quote tailored to your needs.
What are the installation timelines for glass box extensions?
The installation timelines for glass box extensions typically range from 6 to 12 weeks, depending on the complexity of the design and site conditions. Our team will provide a detailed schedule during the consultation process.
