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Glazing blocks (or packers) are invisible on a finished window or door, but they are one of the most important aspects in terms of quality.

When a window is made with the best profile, sealed units and hardware, it will still only perform at its best over a lifetime if it is glazed correctly. The choice of packers can affect the performance in many ways.

Here are some key reasons to choose premium quality glazing packers:

Maintaining squareness. If an installation is glazed properly, the glass unit acts as a brace, keeping the sash rigid and square. To maintain this situation, the glazing packers must not deteriorate or deform over time.

Preventing sash drop. A window or door that is square and true will be less likely to experience sash drop over time. This avoids the need for readjustment and prevents wear and tear on hardware, especially locking points and hinges.

Weight distribution. When glazing packers are placed correctly, good weight distribution is ensured. This also minimises the strain on hinges, extending their life.

Airflow. A window that is packed correctly will allow proper airflow within the sash. This significantly reduces the chance of condensation or corrosion caused by trapped moisture.

Thermal efficiency. Properly glazed windows achieve maximum thermal efficiency because contact between the glass and frame is avoided. This is especially important on aluminium windows.

Damage prevention. Correct packing helps avoid damage to the edges of sealed units. It also prevents the glass unit being submerged in pooled water at the bottom of the sash, reducing the chance of metallic spacers corroding.

Security. Another advantage of a correctly glazed window is that security performance is improved. When locking and hinge points are packed properly, the profile becomes harder to manipulate with burglary tools.

Roto Glas-Tec

Of course, these advantages can only be gained fully if you use the very best glazing packers in order to ensure performance over a lifetime.

100% New material
In the Roto Glas-Tec range of glazing accessories we have over 200 individual products, including many types of packers and the correct tools for installing them.

Roto packers provide high levels of strength and durability because they are made from 100% new material. They don’t contain any reconstituted plastic, which is weaker.

Greener in the long term
The use of brand new plastic could be seen as less environmentally friendly, but you have to consider the whole picture. High quality packers can help maintain the life of a window much better than weaker substitutes, which results in an overall saving in materials over time.

Chemical resistance
The packers are assessed for compatibility with more than 40 different edge sealing compounds to be sure they are not affected by chemicals contained within these products.

Extreme load bearing test
In order to meet the German glazing industry’s technical guidelines (TR3), Roto packers are tested for load-bearing capability under extremes of temperature.

The procedure involves a 6mm wide metal beam being pushed down onto a packer with gradually increasing force until it breaks. The minimum force that each packer must withstand is equivalent to 300 kg. The entire test is conducted three times at very different temperatures: very cold (–20°C), moderate (+23°C) and very hot (+80°C).

At 23°C, the standard support packer can resist a force equivalent to 1,200 kg. When you consider this is equivalent to a small hatchback car, you can see how much development work has gone into the materials and designs of these products.

Are glazing packers a weak or strong link in your window manufacture? It is worth talking to us about the Roto Glas-Tec range.

Types of glazing packers

Each packer in the Roto Glas-Tec range has a specific purpose:

Support packers
Support the weight of the glazing and distribute the load.

Spacer packers
Maintain the correct size of gap between the edge of the glass and the inside of the sash rebate.

Contact point packers
Strengthen areas near locking points and hinges by reducing the profile’s ability to flex.

Bridge spacers
Can perform either the support or spacer role and are also vented to allow airflow.

Compensating blocks
These parts are designed to fit specific profiles, forming an even base on which full packers can be mounted.

Download the Roto Glazing Guide.

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