Extensions & Annexes: Seamlessly Expanding Your Horizon
A successful extension does more than add square footage; it redefines the flow, light, and character of your home. At Sage Developments, we specialise in complex structural extensions and high-specification annexes that breathe new life into existing properties across Bath, Wiltshire, South Gloucestershire and Somerset.

Engineered Full-Width Apertures
Many of our most celebrated projects involve the creation of full-width structural apertures – the seamless replacement of traditional rear elevations with slender steel, glass, and timber. These transformations require significant technical rigour, often necessitating deep-pad foundations and complex steelwork to support the existing fabric while creating expansive, light-filled living spaces within.
- Bringing the Garden In: We are experts in installing floor-to-ceiling glazing, 8m+ sliding doors, and frameless ‘infinity’ glass corners that dissolve the boundaries between your interior and the landscape.
- Thermal Synchronisation: We ensure your new space is highly efficient, utilizing advanced insulation and green roofing solutions (such as sedum roofs) to create a thermally stable environment year-round.
- Architectural Continuity: Whether we are matching local Bath stone or creating a contemporary contrast with zinc and cedar, we ensure the new structure honours the integrity of the original building.
Versatile Annexes & Garden Studios
As the way we live and work evolves, the need for versatile, detached spaces has never been greater. We design and build bespoke annexes that serve as quiet home offices, creative studios, or self-contained guest accommodation. By applying the same “heavy lifting” principles to these smaller structures, we ensure they are built with the same longevity as a primary residence.
- Year-Round Thermal Performance: High-specification insulation and glazing that exceeds standard “garden room” requirements for true four-season use.
- Specialist Roofing & Cladding: Expert installation of standing-seam zinc, cedar shingle, or sedum green roofs to complement your landscape.
- Fully Integrated Utilities: Professional-grade connection of power, high-speed data, and water systems for completely self-contained living.
- Acoustic Engineering: Sound-dampened structures designed for quiet focus, music studios, or private guest suites.
- Planning & AONB Sensitivity: Bespoke designs tailored to meet the stringent requirements of protected landscapes and Heritage sites.
Minimising Disruption, Maximising Quality
We recognise that extending a home often means working while you are still in residence. Our mission is to ensure a “smooth journey” by maintaining an organised, calm, and respectful site. We don’t just manage the build; we manage the environment, ensuring the Sage Quality Constant is delivered with as little disruption to your daily life as possible.
Expand Your Perspective
Ready to reimagine your home’s potential? From the first structural calculation to the final interior finish, Sage Developments provides the professional foresight your project deserves.