Horizontal Sliding

Secondary glazing is a discreet internal window system installed to the inside of an existing window. Available in a range of styles to suit almost any window type, it significantly reduces external noise and improves thermal performance without altering the building's original fabric.

Because secondary glazing is fully reversible and non-intrusive, it is well-suited for use in conservation areas and Grade I and Grade II listed buildings. All Granada systems are manufactured from durable aluminium and can be powder-coated in-house in over 200 RAL colours, allowing the glazing to blend seamlessly with its surroundings.

Secondary glazing is most often specified to address two key challenges: acoustic control and thermal efficiency. No other glazing solution can achieve comparable levels of noise reduction — up to 80%, equivalent to as much as 54dB. It also provides an added layer of security, acting as a secondary barrier should the primary window be compromised.

Designed to work with single-, double-, or triple-glazed timber or uPVC windows, Granada secondary glazing delivers long-term performance unmatched by alternative window systems.

Secondary glazing can be used alongside almost any window type. Traditionally specified to improve the thermal performance of single-glazed timber windows, advances in glazing technology and aluminium frame design have given secondary glazing a renewed and expanded role across both historic and modern buildings.

Its acoustic performance is unmatched by any other glazing solution, delivering significant reductions in noise transmission through single-, double-, and even triple-glazed windows. In high-noise environments, secondary glazing can reduce sound levels by up to 54dB, transforming disruptive external noise into a far quieter internal environment.

Granada secondary glazing is manufactured from durable, slimline aluminium profiles and can be powder-coated in-house in over 200 RAL colours, allowing each system to match the primary window perfectly.

Designed to enhance both thermal and acoustic performance, Granada's secondary glazing combines discreet appearance with long-term durability, delivering reliable performance that stands the test of time.

As a leading name in the glazing industry, Granada ensures that every secondary glazing system combines high performance with a refined, discreet appearance. Our approach is simple: use the finest materials and manufacture to the highest possible standards.

All aluminium frames are produced in-house, using precision machinery to cut, powder coat, arch, and fabricate each unit under one roof. Advanced CNC technology ensures every frame is built accurately as a sealed unit, ready to deliver consistent performance.

Our expertise and commitment to quality set us apart. Unlike some competitors who reduce aluminium content to cut costs, compromising strength, stability, and acoustic or thermal efficiency, Granada maintains robust frame construction, ensuring safe, long-lasting, and high-performing glazing solutions.

Backed by a dedicated team of product developers, every system is designed, tested, and refined using innovative materials and techniques. This meticulous approach ensures that every product leaving our facility meets our high standards.

Draughty windows can make a room feel uncomfortable and increase energy costs by allowing heat to escape. Granada secondary glazing, available with 4mm, 6mm, 6.4mm, or 8.8mm toughened Low E glass, can reduce heat loss by up to 65% while effectively preventing draughts. Low-E glass is specially hard-coated to reflect heat into the room, improving comfort and efficiency.

For optimum performance, secondary glazing is best face-fixed to the interior of the primary window, with an air cavity no greater than 80mm. It enhances thermal efficiency when installed alongside single, double, or triple-glazed timber or uPVC windows.

Granada units can be supplied with or without a hardwood subframe. We recommend a hardwood subframe as it acts as a thermal barrier, preventing the aluminium frame and glass from cooling due to the temperature of the surrounding building fabric.

Our team is on hand to advise on the most suitable glass type, product, and installation method to deliver the best results for your building and requirements.

Secondary glazing is an ideal solution for conservation areas and Grade I and II listed buildings. Its discreet design enhances both acoustic and thermal performance, making it a popular choice within the heritage sector.

Recommended by English Heritage, secondary glazing can be installed without altering the building's original fabric, preserving its character while improving comfort and efficiency.