Balanced Vertical Sliding

Granada secondary glazing units are made to order, allowing bespoke sizes and colours to suit any window. Frames can be bent or arched in-house to match any shape, style, or opening. Custom manufacturing also allows units to align precisely with transoms and mullions, minimising sightlines for a discreet appearance. For larger windows, single units can be stacked or coupled to achieve full coverage without compromising performance or aesthetics.

Secondary glazing is typically specified to address two main challenges: acoustic or thermal performance. Alongside the air cavity, the type of glass chosen plays a crucial role in resolving these issues. All Granada units are manufactured as standard with 4mm toughened glass, offering enhanced security and safety. Unlike some providers who use float glass, which can shatter dangerously, toughened glass minimises risk and meets high safety standards.

We offer a range of glass types, carefully selected for optimal performance, including variations in thickness and coatings.

Acoustic performance: When installed with an air cavity of 150–200mm, the correct glass can reduce noise by up to 80% (54 dB). Typical traffic noise can often be managed with 6.4mm or 6.8mm clear acoustic glass, while louder environments may require 8.8mm acoustic glass for maximum sound reduction.

Thermal performance: Draughts through primary windows can make spaces uncomfortable and increase energy costs. For improved thermal efficiency, we recommend 4mm, 6mm, 6.4mm, or 8.8mm toughened Low-E glass, which reflects heat back into the room, keeping interiors warmer in winter and cooler in summer.

The choice of glass can affect the overall cost. We advise speaking directly with our team to ensure the specification is tailored to your requirements, delivering both practical performance and cost efficiency without unnecessary over-specification.

Secondary glazing offers a range of benefits, including up to 80% reduction in noise (54 dB) and a 65% decrease in heat loss. A small air cavity between the primary window and the secondary glazing plays a vital role in both acoustic and thermal performance. The recommended cavity varies depending on the issue you are addressing.

Acoustic performance: For optimal noise reduction, we advise an air cavity of 150–200mm. This reveal-fix installation positions the secondary glazing within the window reveal and, when combined with clear acoustic glass in 6.4mm, 6.8mm, or 8.8mm thicknesses, can reduce sound by up to 80% (54 dB).

Thermal performance: For improved energy efficiency, we recommend a face-fixed installation with an air cavity of up to 80mm. When combined with Low E glass, this can reduce heat loss by up to 65%, keeping interiors warmer in winter and cooler in summer.

Granada's team can advise on the most suitable glass, cavity, and installation method, providing a tailored solution to meet your specific acoustic or thermal requirements.