Granada Glazing supplies secondary glazing systems to over 500 approved trade partners across the UK, alongside direct supply to architects, main contractors, heritage consultants, and facilities managers. Every unit is manufactured to order at our Dinnington facility and delivered with the technical documentation specifiers need.
Understanding project goals, performance requirements, and any heritage or planning considerations before specification begins.
Precise measurements that account for reveal depth, installation method, and glass specification. Right first time, every time.
Aluminium secondary glazing units manufactured in-house at our 40,000 sq ft facility. Consistent quality, reliable lead times.
Supplied to your approved installer network or directly to the site. Minimal disruption to occupants and programme.
Granada Glazing has been manufacturing secondary glazing since 1980. Over 45 years, we have produced more than one million frames across every building type. Listed heritage properties, NHS hospitals, university buildings, hotels, and residential developments.
Our 40,000 sq ft facility in Dinnington, South Yorkshire houses CNC machinery, in-house metal forming, and a full powder coating line. That means every secondary glazing unit leaves our factory finished to specification, with over 200 RAL colours available as standard.
Annual output runs to approximately 25,000 frames, roughly 100 per day. The scale of production gives architects, contractors, and trade partners the lead time reliability that larger commercial programmes demand.
Granada is listed on NBS Source, holds BSI ISO 9001:2015 accreditation, and offers a RIBA-Approved CPD for specifiers working with secondary glazing in heritage and commercial applications.
The most widely specified product in the range. Two to five independently sliding sashes on precision-engineered aluminium tracks. Suited to casement, hinged, and any window with vertical bars. Units up to 4,934mm wide. Tested acoustic performance: 49dB Rw with 6mm primary glass and 6.8mm acoustic laminate.
Designed for traditional sash windows. Spring-balance operation holds each sash at any chosen position. Available in tilt-in (TBVS) and slide-past (SPBVS) configurations. Units up to 3,325mm tall. The appropriate specification where primary sash windows must be preserved without alteration.
Opens inwards with slim 60–72mm sightlines and multi-point locking. The only product in the range to accommodate double-glazed sealed units (24mm and 28mm). Available with integral venetian blinds, as specified for the NHS hyper-acute stroke unit at Hallamshire Hospital, Sheffield.
Custom solutions for arched, bay, curved, circular, and angled openings. Quoted individually. Backed by a 10-year guarantee. Used across some of the most complex listed and heritage buildings in our project portfolio.
Granada's secondary glazing was specified across Grade II listed buildings at Oxford University's Reuben College, combining the Radcliffe Science Library and historic Abbot's Kitchen in a complex multi-building refurbishment. The project required a discreet solution that preserved the original architectural character while achieving 65% thermal improvement and up to 54dB noise reduction. The works also supported the University's wider decarbonisation strategy.
EXPLORE OUR CASE STUDYSecondary glazing is frequently misunderstood as a second-best solution. The acoustic and thermal data show otherwise.
Properly specified aluminium secondary glazing delivers up to 54dB noise reduction, significantly more than double or triple glazing, both of which perform at approximately 35dB Rw. The critical factor is cavity depth. A 150–200mm glass-to-glass reveal fix installation with acoustic laminated glass achieves optimum performance; the 49dB Rw figure for our tested Horizontal Sliding unit is based on 6mm primary glass and 6.8mm acoustic laminate.
Secondary glazing achieves up to 65% heat loss reduction. Our Horizontal Sliding unit achieves 1.5 W/m²K with 4mm Low-E glass and an 80mm air gap. At Hallamshire Hospital, hinged units with Low-E glass achieved 1.9 W/m²K centre-pane, a meaningful improvement in a live clinical environment.
Specifiers requiring U-value tables, acoustic test certificates, or glass specification data can access our full library of technical downloads.
TECHNICAL DOWNLOADSWith over four decades of experience, Granada Glazing has led the way in commercial and heritage secondary glazing across the UK.
Our industry recognised accreditations and partnerships ensure every project meets the highest standards of performance, compliance, and craftsmanship.
Our team provides clear, practical guidance to help you specify and install with confidence.
Secondary glazing is an independent inner window fitted to the room side of an existing window frame. It is not a replacement for the primary window. Secondary glazing improves thermal insulation, reduces noise intrusion, and adds a layer of security without altering the external appearance of the building. For listed and heritage buildings, it is typically the only glazing intervention that does not require Listed Building Consent.
Secondary glazing is fitted on the inside of the existing window and does not alter the external appearance of the building. It is generally permitted development and does not require planning permission. For properties in conservation areas or subject to Listed Building Consent requirements, secondary glazing is typically the recommended intervention precisely because it is non-invasive and reversible.
Granada is listed on NBS Source, where full product specifications are available for download. Architects and specifiers can also contact our technical team directly for project-specific guidance, or access our technical downloads for data sheets, installation guides, and acoustic test results.
Our technical team can advise on product selection, cavity depth, glass specification, and installation method. Call 01909 499899 or use the enquiry form.
Granada is listed on NBS Source. Download specifications, access technical drawings, and contact our commercial team for project support.
Access trade pricing, technical drawings, and the online price generator through the Granada trade portal.
