Custom Secondary Glazing: The Ultimate Guide To Custom Secondary Glazing

· 5 min read
Custom Secondary Glazing: The Ultimate Guide To Custom Secondary Glazing

The Comprehensive Guide to Custom Secondary Glazing: Enhancing Performance Without Compromising Heritage

In the realm of architectural conservation and energy efficiency, property owners typically deal with a tough dilemma. While modern-day double or triple glazing uses remarkable thermal and acoustic efficiency, setting up these units in period residential or commercial properties, noted buildings, or preservation areas is typically limited by law or aesthetic factors to consider. In addition, the structural stability of older window frames may not support the weight of heavy double-glazed units.

Customized secondary glazing has become the premier option to this obstacle. By installing a discreet, supplementary internal window behind the existing main window, it is possible to attain modern standards of convenience while protecting the initial character of the building. This post explores the mechanics, benefits, and numerous setups of customized secondary glazing systems.


What is Custom Secondary Glazing?

Secondary glazing includes the installation of an independent internal window frame, fitted on the room side of the existing main window. Unlike mass-produced options, "customized" secondary glazing is bespoke-engineered to match the exact dimensions, lines, and performance of the initial window.

Whether a building includes big Victorian sash windows, arched Gothic frames, or commercial steel casements, custom-made secondary units are designed to be as inconspicuous as possible. They are generally built from slimline aluminum frames and high-performance glass, ensuring that the visual influence on the structure's interior is very little.


The Core Benefits of Custom Secondary Glazing

The choice to install secondary glazing is normally driven by among four primary aspects: thermal insulation, acoustic dampening, security, or heritage conservation.

1. Thermal Insulation and Energy Efficiency

Heat loss through older, single-glazed windows is a substantial contributor to high energy bills and carbon footprints. Custom-made secondary glazing produces a pocket of insulating air in between the 2 panes of glass. When combined with contemporary Low-E (low-emissivity) glass, this can lower heat loss by as much as 60%.

2. Superior Acoustic Performance

While standard double glazing works at retaining heat, it is typically less effective at obstructing low-frequency noise, such as traffic or airplane. Customized secondary glazing excels in this area since of the "air space." By keeping a space of 100mm to 200mm between the main and secondary glass, the system creates an effective acoustic buffer that can reduce sound levels by approximately 50 decibels (dB), successfully turning a noisy city street into a peaceful sanctuary.

3. Conservation of Heritage

For structures with "Listed" status, replacing windows is frequently prohibited. Customized secondary glazing is normally viewed favorably by preparing officers because it is a reversible internal modification. It permits the initial timber or metal frames to remain intact on the outside.

4. Enhanced Security

Adding a second layer of glass offers a significant physical barrier against burglars. Customized systems can be fitted with strengthened or laminated glass, which is incredibly difficult to penetrate, providing comfort for home owners.


Kinds Of Custom Secondary Glazing Units

Considering that every window is different, a number of configurations exist to guarantee that the secondary unit does not hinder the operation of the initial window.

  • Horizontal Sliders: Ideal for casement windows or ribbon windows. The panels slide on integrated tracks for simple access.
  • Vertical Sliders: Designed particularly for traditional sash windows. These systems make use of spring balances to imitate the movement of the original sash.
  • Hinged Units: These open like a standard door or window. They are frequently used when total access to the main window is needed for cleaning or ventilation.
  • Lift-Out Units: Best for windows that are seldom opened. The entire glazed panel can be raised out of the frame when maintenance is required.
  • Repaired Units: These are completely connected to the frame and are used in locations where ventilation by means of that specific window is not required.

Comparing Window Solutions

When weighing options for window upgrades, it is valuable to see how custom-made secondary glazing compares to standard replacement windows.

Table 1: Secondary Glazing vs. Replacement Double Glazing

FeatureCustom Secondary GlazingReplacement Double Glazing
Aesthetic ImpactVery little; maintains original outside.High; changes the structure's exterior.
Acoustic PerformanceSuperior (due to bigger air gap).Moderate.
Planning PermissionSeldom needed (even for noted structures).Typically needed in conservation locations.
Installation MessMinimal; no structural changes.Considerable; requires elimination of old frames.
CostTypically more cost-effective.Can be very expensive for bespoke wood.
Thermal EfficiencyHigh (equivalent to double glazing).Really high.

Technical Specifications: Glass and Performance

The performance of a customized secondary glazing system is largely figured out by the type of glass picked. Specialists frequently recommend particular glass types based on the primary goal of the setup.

Table 2: Glass Performance Metrics

Glass TypeMain BenefitNoise Reduction (Est)Thermal Improvement
4mm ToughenedSecurity & & Basic Insulation35-38 dBModerate
6mm FloatRequirement Performance39-41 dBModerate
6.4 mm LaminatedSecurity & & UV Protection42-45 dBExcellent
6.8 mm AcousticOptimum Sound Proofing48-52 dBGreat
4mm Low-EMaximum Heat Retention35-38 dBExcellent

The Custom Installation Process

To ensure the highest efficiency, the installation of custom-made secondary glazing follows a systematic expert process:

  1. Surveying and Measurement: A technician takes accuracy measurements of the window reveal. Out-of-square openings are kept in mind so the custom-made frame can be manufactured to make up for structural shifts in older buildings.
  2. Bespoke Manufacturing: The frames are powder-coated to match the interior design (basic white, anthracite, or any RAL color) and the glass is cut to size.
  3. Preparation: Existing window sills and reveals are cleaned up. Any essential timber sub-frames are installed to supply a level mounting surface area.
  4. Fitting: The secondary systems are secured into the expose. Unique care is taken to guarantee an airtight seal, as air leakage is the primary reason for poor acoustic and thermal efficiency.
  5. Ending up: Perimeter seals are used, and the movement of sliders or hinges is evaluated for smooth operation.

Regularly Asked Questions (FAQ)

1. Does secondary glazing cause condensation?

If installed incorrectly, it can. Nevertheless, expert custom secondary glazing is designed to handle this. The internal unit creates an airtight seal versus the space's warm, wet air, while the main window is enabled to "breathe" somewhat. This prevents the moisture from reaching the cold outer pane where it would generally condense.

2. Is secondary glazing obvious from the outside?

Usually, no. Due to the fact that the frames are slim and aligned with the existing window's meeting rails and mullions, they are virtually undetectable from the street.  secondary double glazing near bournemouth  is why they are the preferred option for historical conservation.

3. Can I still open my windows for ventilation?

Yes. By choosing the appropriate kind of unit (such as a vertical or horizontal slider), the secondary glazing can be opened in tandem with the main window to permit for fresh air circulation.

4. How long does the installation take?

Most property setups can be completed within a single day. Due to the fact that there is no need to remove the initial windows, there is really little dust or structural interruption.

5. Can secondary glazing aid with UV fading?

Yes. By picking laminated glass for the secondary unit, homeowner can block as much as 99% of UV rays, securing furniture, artwork, and materials from sun damage.


Custom secondary glazing represents an advanced intersection of modern-day engineering and architectural heritage. It offers a pragmatic option for those residing in older homes who wish to reduce their environmental effect and delight in a quieter living space without compromising the historic stability of their home.

By providing remarkable soundproofing compared to basic double glazing and offering a significant thermal barrier, custom units are an investment in both the worth of the property and the quality of life for its residents. For anybody dealing with the difficulties of drafty, noisy, or secured windows, custom secondary glazing stands as the most versatile and efficient upgrade available on the modern market.