Glazing works on historic buildings? Our window putties, EGOPUTTIES, have proven themselves for decades and are perfect for single glazing for windows to be restored.

Window putty for single glazing – the classic

Overview EGO putty

Possibilities of glazing systems.

Window putties from EGO are produced using mountain chalk from Kaltenbrunn in Upper Bavaria which we mine ourselves. They have proven themselves as excellent materials both here and abroad over decades. Window putty has the advantage of adequately sealing single glazing in listed buildings without damaging the property to be renovated. It also guarantees a seal in accordance with DIN 18545: Sealing of glazing with sealants in accordance with Groups 1-5 of the “Chart for determining the load-bearing groups for window glazing (RoTa)” developed by the Institut für Fenstertechnik e.V., Rosenheim.

Window putties from EGO are excellently suited to:

  • Single glazing in timber and metal windows as well as combinations of these
  • Greenhouse glazing, industrial glazing, lead glazing, and much more


Working with window putty – How to do it right

The windows are always a significant weak point in heat insulation, especially in older buildings. The single glazing of the windows does not keep the outside temperature away as well as the laminated glass of the new window models.

Influences of UV light, temperature and weather don’t merely put the windows and window sashes under strain; they also have an effect on the putty joint. If the window putty is already porous, it is high time to plan a renovation to maintain the old windows. One pane in the window is blocked and mechanically secured with pins and clips. The window putty is not only used to seal the window; it also ensures that the glass pane is held firmly in place. 

Especially when it comes to listed buildings, the preservation and professional restoration and renovation of old windows is a major issue. However, single panes are also glazed in other areas, such as older conservatories and greenhouses. For this reason, it makes sense to find out in advance about the stress group and the window putty suitable for the application. For interrelated work processes, such as renewing window putty and repainting, it’s advantageous if all materials come from one source and are coordinated with each other. At EGO, you will find the right putty syringe, EGOFIX PUTTY PRESS, the different types of putty as well as experts who are happy to advise you.

Are all putties the same? 

Well, yes...but also no. EGO offers different types of putty for different stresses and application areas. For lead glazing, there is EGO spreading putty, which is easy to spread. EGOSIT sets quickly at first and takes 5-10 years to harden completely. This makes it relatively durable. Greenhouse putty is injected and is the only putty that does not need to be painted over. EGO linseed oil putty is the purest putty and consists only of chalk and linseed oil.

In addition, EGO offers special glazing putties, the SB 11 and SB 25. The SB 25 as a soft plastic glazing putty is suitable for all stress groups (1 -5) according to RoTa.

With EGO products, you have a wide range available for your building projects.
A further advantage is that EGO products use our own regional Kaltenbrunn mountain chalk, which is an additional benefit in terms of preventing climate change!


Apply window putty like a pro!
Before the new putty can be applied, you first need to remove the old putty. It is best if the window sash is removed beforehand and placed horizontally on the work surface. In addition to the pins or clips, the glass pane is also held in place by the window putty and should now no longer be able to fall out. To remove the old, hard putty residues from the joint or putty template, we recommend using a screwdriver or an old knife. This work should be done very carefully and with as little pressure as possible. Once the putty is removed on one side, all joints must be thoroughly vacuumed out and cleaned using a damp cloth. 

TIP: Old putty is often difficult to remove
To avoid breaking the glass pane when removing the putty, you can heat the putty for a while using a hairdryer, for example. However, EGO recommends using an infrared heater, as improper use of the hairdryer can lead to stress cracks in the glass or damage to the paintwork. Heating makes the older putty easier to remove. 

Before applying the new glazing putty, the substrate should be clean, dry and free of grease. Primer must be applied to absorbent substrates, such as untreated wood or concrete. The substrate must not be able to absorb linseed oil from the putty!

The putty is applied with a putty knife. Now, you must pay close attention to prevent air bubbles or cavities. It is best to work the applied window putty into the joints in sections. For a smooth surface and even skin formation, the excess putty must then be removed from the joint with a polished putty knife and the joint must be smoothed over. Now you can do the next window because the putty needs time to dry.

Optimum temperatures for putty
When applying window putty, you should pay attention to weather conditions and the application temperature and ambient temperature. Window putty should be stored in a cool, dry and frost-free place. The best temperatures to apply putty are between 5 and 30 degrees Celsius. Temperatures should also never be lower than this during the skin formation and drying phase.

Take a look! Old windows with new putty!

You will find numerous descriptions of how to putty glass panes online.
One problem that some DIY restorers might face right at the beginning is opening the old double panes of wooden windows, especially on skylights.

A good guide on how to apply putty and remove excess putty with the putty knife can be found here.

Painting over the window putty
The video already addresses painting over the window putty. Window putty takes a long time to harden compared to other sealants. Temperature fluctuations cause material expansion, which means that the putty must remain plastic, so the long hardening time is advantageous. This is why elastic varnishes and paints should be used to paint over window putty.

It takes some time to apply window putty. This is because once the skin has formed sufficiently, after 8 weeks at the latest (finger test), the putty chamfer as well as the room-side putty must be painted over with a weatherproof paint, e.g. acrylic or alkyd paint! The exception to this is EGO GREENHOUSE PUTTY. Here, it is not necessary to paint over the putty.

The coating serves to protect the putty from oxygen in the atmosphere in order to delay the oxidation of the linseed oil and thus increase the service life of the putty chamfer. This means that you should also ensure an even layer thickness of paint. You should apply 1-2 mm of paint/varnish onto the glass surface to allow rainwater to run off better and to protect the putty from oxygen in the atmosphere.