Why All The Fuss Over Custom Secondary Glazing?

· 5 min read
Why All The Fuss Over Custom Secondary Glazing?

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

In the realm of architectural preservation and energy performance, homeowner often deal with a challenging dilemma. While modern-day double or triple glazing provides exceptional thermal and acoustic efficiency, setting up these units in period residential or commercial properties, noted structures, or conservation locations is typically restricted by law or visual factors to consider. Additionally, the structural integrity of older window frames might not support the weight of heavy double-glazed systems.

Custom secondary glazing has emerged as the premier option to this difficulty. By installing a discreet, extra internal window behind the existing primary window, it is possible to achieve contemporary standards of comfort while protecting the initial character of the building. This post explores the mechanics, benefits, and various configurations of customized secondary glazing systems.


What is Custom Secondary Glazing?

Secondary glazing includes the setup of an independent internal window frame, fitted on the space side of the existing main window. Unlike mass-produced services, "custom-made" secondary glazing is bespoke-engineered to match the exact measurements, lines, and performance of the initial window.

Whether a building includes large Victorian sash windows, arched Gothic frames, or industrial steel sashes, customized secondary systems are designed to be as unobtrusive as possible. They are generally constructed from slimline aluminum frames and high-performance glass, making sure that the visual effect on the building's interior is minimal.


The Core Benefits of Custom Secondary Glazing

The decision to install secondary glazing is typically driven by one of 4 main elements: thermal insulation, acoustic dampening, security, or heritage preservation.

1. Thermal Insulation and Energy Efficiency

Heat loss through older, single-glazed windows is a considerable contributor to high energy costs and carbon footprints. Customized secondary glazing develops a pocket of insulating air between the 2 panes of glass. When combined with modern-day Low-E (low-emissivity) glass, this can lower heat loss by as much as 60%.

2. Superior Acoustic Performance

While basic double glazing is reliable at maintaining heat, it is typically less effective at obstructing low-frequency sound, such as traffic or aircraft. Custom-made secondary glazing masters this location due to the fact that of the "air gap." By keeping a gap of 100mm to 200mm between the primary and secondary glass, the system develops a powerful acoustic buffer that can decrease sound levels by as much as 50 decibels (dB), successfully turning a loud city street into a quiet sanctuary.

3. Conservation of Heritage

For structures with "Listed" status, replacing windows is frequently prohibited. Custom-made secondary glazing is generally viewed favorably by planning officers because it is a reversible internal adjustment. It enables the original wood or metal frames to remain intact on the exterior.

4. Boosted Security

Including a second layer of glass supplies a considerable physical barrier versus trespassers. Custom-made systems can be fitted with toughened or laminated glass, which is incredibly difficult to penetrate, offering peace of mind for property owners.


Types of Custom Secondary Glazing Units

Since every window is various, numerous configurations exist to guarantee that the secondary system does not impede the operation of the original window.

  • Horizontal Sliders: Ideal for casement windows or ribbon windows. The panels slide on integrated tracks for easy access.
  • Vertical Sliders: Designed specifically for conventional sash windows. These units use spring balances to mimic the movement of the initial sash.
  • Hinged Units: These open like a basic door or window. They are typically used when overall access to the main window is required for cleansing or ventilation.
  • Lift-Out Units: Best for windows that are seldom opened. The whole glazed panel can be raised out of the frame when maintenance is needed.
  • Fixed Units: These are permanently connected to the frame and are used in areas where ventilation by means of that specific window is not necessary.

Comparing Window Solutions

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

Table 1: Secondary Glazing vs. Replacement Double Glazing

FeatureCustom Secondary GlazingReplacement Double Glazing
Visual ImpactMinimal; maintains original exterior.High; modifications the building's facade.
Acoustic PerformanceSuperior (due to bigger air gap).Moderate.
Planning PermissionRarely needed (even for noted structures).Often required in sanctuary.
Setup MessVery little; no structural changes.Considerable; requires removal of old frames.
CostTypically more affordable.Can be extremely costly for bespoke wood.
Thermal EfficiencyHigh (comparable to double glazing).Very high.

Technical Specifications: Glass and Performance

The efficiency of a custom-made secondary glazing system is largely figured out by the kind of glass picked. Specialists typically suggest specific glass types based on the primary objective of the installation.

Table 2: Glass Performance Metrics

Glass TypeMain BenefitSound Reduction (Est)Thermal Improvement
4mm ToughenedSecurity & & Basic Insulation35-38 dBModerate
6mm FloatStandard Performance39-41 dBModerate
6.4 mm LaminatedSecurity & & UV Protection42-45 dBGood
6.8 mm AcousticMaximum Sound Proofing48-52 dBGood
4mm Low-EMaximum Heat Retention35-38 dBOutstanding

The Custom Installation Process

To ensure the greatest efficiency, the installation of custom secondary glazing follows a methodical professional process:

  1. Surveying and Measurement: A professional takes precision measurements of the window expose. Out-of-square openings are noted so the custom frame can be produced to compensate for structural shifts in older buildings.
  2. Bespoke Manufacturing: The frames are powder-coated to match the interior design (standard white, anthracite, or any RAL color) and the glass is cut to size.
  3. Preparation: Existing window sills and exposes are cleaned up. Any needed lumber sub-frames are installed to supply a level mounting surface area.
  4. Fitting: The secondary systems are secured into the reveal. Special care is required to guarantee an airtight seal, as air leakage is the primary cause of bad acoustic and thermal performance.
  5. Ending up: Perimeter seals are applied, and the motion of sliders or hinges is tested for smooth operation.

Often Asked Questions (FAQ)

1. Does secondary glazing cause condensation?

If set up improperly, it can. However, professional customized secondary glazing is created to manage this. The internal system creates an airtight seal versus the space's warm, wet air, while the primary window is enabled to "breathe" a little. This avoids the moisture from reaching the cold outer pane where it would usually condense.

2. Is secondary glazing obvious from the exterior?

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 invisible from the street. This is why they are the favored option for historic conservation.

3. Can I still open my windows for ventilation?

Yes. By choosing the proper kind of system (such as a vertical or horizontal slider), the secondary glazing can be opened in tandem with the primary window to permit fresh air flow.

4. The length of time does the installation take?

Most domestic setups can be finished within a single day. Since there is no requirement to eliminate the initial windows, there is very little dust or structural disruption.

5. Can secondary glazing assist with UV fading?

Yes. By choosing laminated glass for the secondary system, home owners can block up to 99% of UV rays, safeguarding furniture, artwork, and materials from sun damage.


Custom secondary glazing represents a sophisticated intersection of modern-day engineering and architectural heritage. It supplies a pragmatic service for those residing in older homes who want to lower their environmental effect and enjoy a quieter home without sacrificing the historical integrity of their property.

By using remarkable soundproofing compared to basic double glazing and providing a substantial thermal barrier, custom-made units are an investment in both the value of the home and the lifestyle for its residents. For  secondary glazing romiley  handling the challenges of drafty, loud, or safeguarded windows, custom-made secondary glazing stands as the most versatile and effective upgrade available on the modern market.