The 10 Worst Secondary Glazing Fitting Mistakes Of All Time Could Have Been Prevented

· 5 min read
The 10 Worst Secondary Glazing Fitting Mistakes Of All Time Could Have Been Prevented

The Ultimate Guide to Secondary Glazing Fitting: Enhancing Efficiency and Comfort

In the quest for enhanced energy performance and acoustic performance, many residential or commercial property owners discover themselves at a crossroads. While double glazing is the standard for contemporary builds, it is not constantly a feasible or acceptable alternative for heritage homes, noted structures, or those situated in sanctuary. This is where secondary glazing acts as a premier solution. Secondary glazing includes the setup of a discrete, internal window frame designed to sit behind the existing main window.

This guide provides a thorough summary of the fitting procedure, the different types of secondary glazing readily available, and the tangible advantages of this non-intrusive setup.

The Benefits of Secondary Glazing

Before exploring the intricacies of the fitting procedure, it is important to understand why this technique is preferred over complete window replacement in numerous scenarios. Secondary glazing uses a special set of benefits that deal with both comfort and conservation.

Thermal Insulation

Secondary glazing creates an insulating layer of air in between the existing glass and the new pane. This "dead air" space considerably minimizes heat transfer, assisting to maintain a consistent internal temperature. Properties typically see a decrease in heat loss of as much as 60%, resulting in lower energy expenses.

Acoustic Performance

For homes located near busy roadways, trains, or flight paths, noise pollution is a considerable issue. Because the secondary pane is separate from the main window, it breaks the path of sound vibrations better than a standard double-glazed unit. When fitted with specialized acoustic glass, sound reduction can go beyond 80%.

Condensation Control

By sealing the inner space from the cold surface area of the primary window, secondary glazing helps balance the temperature level. When properly aerated, it can substantially decrease or even eliminate condensation concerns that lead to mold growth.

Security and Conservation

In listed structures where initial lumber frames can not be removed, secondary glazing adds a layer of security without changing the outside visual. It functions as a physical barrier to trespassers and can be fitted with toughened or laminated glass for extra protection.


Types of Secondary Glazing Units

Choosing the correct unit type is the primary step in an effective fitting. The choice often depends upon the performance of the existing window.

Table 1: Comparison of Secondary Glazing Types

System TypeBest Suited ForSecret Advantages
Horizontal SliderBigger windows, Casement windowsSmooth operation; simple access to the main window.
Vertical SliderDuration Sash windowsMatches the visual appeals and function of conventional moving sashes.
Hinged UnitsArched or strangely shaped windowsOpens like a door; offers full access for cleansing.
Lift-Out UnitsWindows seldom openedMost economical; sleek and minimalist look.
Fixed UnitsNon-opening windowsOptimum airtight seal; suitable for purely thermal/acoustic needs.

Pre-Installation: Tools and Preparation

An effective fitting is predicated on accurate measurement and having the correct tools on hand.  ruislip secondary glazing windows  should choose between a "face repair" (fitting the frame directly onto the primary window frame) or a "expose repair" (fitting the frame into the internal window recess).

Table 2: Essential Tools for Secondary Glazing Fitting

ToolPurpose
Laser Measure/ Steel TapeTo guarantee millimetre-perfect dimensions.
Spirit LevelTo make sure the frame is perfectly horizontal and vertical.
Power Drill/DriverFor securing the sub-frame to the masonry or timber.
Low-Modulus SiliconeTo create an airtight seal around the boundary.
Countersink BitTo guarantee screw heads sit flush with the frame.
Cleaning AgentsTo clean up the existing window before it is sealed.

The Step-by-Step Fitting Process

The list below actions outline the professional method to fitting secondary glazing, guaranteeing longevity and optimum efficiency.

1. Surveying and Measuring

The most vital phase is the preliminary survey. Measurements should be taken at 3 points (top, middle, and bottom for width; left, middle, and right for height). If the window runs out square, the biggest measurement is usually utilized for the frame, while the smaller sized dimension dictates the size of any timber "grounds" or packers needed to level the unit.

2. Preparing the Sub-Frame

A lot of secondary glazing systems are mounted on a timber sub-frame. This sub-frame acts as a bridge in between the existing masonry and the brand-new aluminium frame. It ought to be pre-drilled and dealt with to avoid rot if it is being installed versus older stone or brickwork.

3. Cleaning up the "Void"

Once the system is set up, the interior surface of the primary window and the exterior surface of the secondary window ended up being challenging to gain access to. It is essential to clean both surface areas thoroughly with streak-free glass cleaner and a microfiber fabric. Any dust or fingerprints left will be completely visible inside the cavity.

4. Fixing the Frame

The frame is positioned into the expose or onto the face of the primary window. Using a spirit level, the installer guarantees the system is perfectly plumb. If the walls are irregular, little plastic shims or packers are inserted behind the frame to guarantee the system does not "bow" when the screws are tightened up.

5. Sealing for Performance

To accomplish the guaranteed acoustic and thermal benefits, the system needs to be airtight. A bead of premium, paintable acrylic or silicone sealant is used around the entire perimeter of the secondary frame where it fulfills the wall or wood. This avoids "acoustic leak" and keeps draughts at bay.

6. Adjusting and Testing

For sliding or hinged systems, the final step includes adjusting the tension and checking the locks. For horizontal or vertical sliders, the installer makes sure that the panels slide efficiently without catching on the frame.


Upkeep and Care

Standard maintenance for secondary glazing is very little however necessary to make sure functionality.

  • Track Cleaning: For moving systems, the bottom tracks need to be vacuumed frequently to eliminate dust and particles that can impede movement.
  • Lubrication: Occasionally applying a dry silicone spray to the runners of sliding units will preserve smooth operation.
  • Ventilation: It is advised to leave a little space for air circulation if the main window is prone to severe wetness, avoiding trapped humidity in between the 2 panes.

Frequently Asked Questions (FAQ)

Is secondary glazing as excellent as double glazing?

In regards to sound insulation, secondary glazing is typically superior to double glazing because the bigger air space (typically 100mm to 200mm) acts as a better sound buffer. For thermal performance, premium double glazing is somewhat better, but secondary glazing is a highly efficient runner-up that keeps the structure's initial character.

Can secondary glazing be DIY fitted?

While numerous producers supply "ready-to-fit" packages, expert installation is suggested for bigger systems or noted structures. An expert installer understands how to handle out-of-square openings and guarantee the airtight seal necessary for acoustic performance.

Will it trigger condensation?

If fitted incorrectly without thinking about the "breathing" of the main window, condensation can take place. Expert fitters typically include little trickle vents or make sure the main window is somewhat "leaky" to enable moisture to escape, while the secondary window remains the primary thermal barrier.

How much space is needed for the fitting?

A basic expose fix needs around 50mm to 100mm of depth within the window recess. If the recess is shallow, a "face repair" can be utilized, where the system is mounted directly onto the surface of the wall or the window frame itself.

Is preparing permission needed?

In the huge majority of cases, no. Since secondary glazing is an internal alteration that does not alter the external look of the home, it generally falls under "permitted advancement." However, it is constantly smart to examine with regional authorities if the building is Grade I noted.


Secondary glazing fitting is an art of precision and preservation. By adding a discreet, high-performance layer to existing windows, homeowner can delight in the comforts of modern living-- warmth, silence, and security-- without sacrificing the architectural heritage of their homes. Whether selecting a vertical slider for a Victorian sash or a smooth lift-out unit for a modern-day flat, the key to success depends on careful measurement, proper sealing, and choosing the right system for the specific environment.