Glazing packers: the invisible heroes in every window

by Daniel Pinger on Jan 13, 2023

Glazing packers: the invisible heroes in every window

Glazing packers are relatively small components that can be found in practically every window. But why have most people never heard of glazing packers? The answer is quite simple: because they are installed inside. Yet they have several very important tasks to fulfil.

What are glazing packers for?

Firstly, the glazing packers have to take the entire weight of the glass pane in the frame. It does not matter whether the glazing is in a door or a window. In other words, the glass never rests directly on the window frame, but only on the glazing packers on the sides of the pane. As a rule, a pane of glass is only laid on at two points. The support does not always have to be at the bottom left and right.

There are different patterns of movement of the door or window sashes and the glazing blocks provide support at the points of greatest load. Therefore, the glass itself lies more or less freely in the frame. Of course, it is wedged tightly with the glazing packers to prevent slipping, but only at certain points. This means that the frame and the glass pane are never in direct contact. This prevents possible damage to the glass caused by mechanical loads on the frame, for example by wind load or mere opening.

Secondly, the glazing packers take on a stiffening function together with the respective frame, which in turn gives stability to the frame itself.

Thirdly, the "floating" support of the glass pane creates a surrounding cavity that fulfils an important function. It serves to ventilate the rebate space and equalise vapour pressure. As a result, moisture cannot accumulate and mould and deposits are avoided.

What are glazing blocks made of?

In the past, hardwood was used, but today plastic glazing packers are the first choice. We use polypropylene for our parts, which offers many advantages for the intended function. The blocks we offer have the great advantage that they have a high material strength and are extremely dimensionally stable. They have a negligible coefficient of expansion and cannot absorb moisture. They are also more cost-effective than wooden blocks. Our glazing packers are each assigned to a thickness in their colours. This means that quick, intuitive access to the right block saves time and nerves during installation, whether on site at the customer's or in the workshop.

What types of glazing packers are there?

As a rule, two types are sufficient. The first is the support packers described above, whose task is to support the weight of the glass pane and distribute it over the frame. As a rule, two, in some cases four, of these are used in a window. They serve as a support for the glass pane, so to speak. They are always installed one block length inwards on the outer sides of the pane. This does not always have to be at the bottom, but can also be on the inside at the bottom and diagonally at the top of the side frame in the case of casement frames, for example.

There are also spacer blocks. Their task is to fix the glass pane firmly in the frame at the points that are not the main points of attachment of the pane weight. In principle, they are used in the same way as the support blocks. In the case of different movement sequences of the window or door, they can also take over the task of a support block.

In addition to the glazing packers described, there are also some auxiliary blocks for more specific tasks.

For example, glazing rebate inserts can compensate for unevenness of the frame. Thus, the corresponding glazing packers lie better, i.e. over the entire surface, and can fully fulfil their function.

Furthermore, block bridges are used. These can provide air circulation in some profiles, because they have a continuous opening on the underside.