All information on our website www.dgsgroup.co.uk and other DGS publications are for information and guidance only. We have taken all reasonable due care to ensure the information contained within our website and publications is accurate and current but we do not accept any liability for any inaccuracy or omission. It is the customers sole responsibility to ascertain compatibility and suitability of products. For any specific applications we recommend that you seek further advice.


It is the customers sole responsibility to ascertain compatibility and suitability of products. If you are unsure as to the suitability of a product please seek further advice.

Trading Terms

Trading Application Form

Of course there is a lot of small print. In a nutshell, the customer is required to pay within the agreed time and the supplied goods remain the property of DGS until they are paid for.

You can download a Trade Application Form by clicking the icon to the right. Please return completed forms to.

DGS Group Plc.
Sycamore Road
Trent Lane Industrial Estate
Castle Donington
DE74 2NW

PDF Download

Glass and Glazing Dec 2013: Compatibility Matters

What happens when incompatibility occurs?

Incompatibility may manifest itself in a number of different ways.

  • Incompatibility between primary and secondary sealant. Softener migrates from the secondary sealing through the primary sealant into the inner space of the IG unit.
  • The wrong fixing of glazing blocks. Silicone used to fix a setting block may come into direct contact with the secondary sealant and the laminated glass. This may have a detrimental effect on both the edge seal and the PVB foil. One way to avoid this is to fix the setting block with a compatible silicone to the sash.
  • Stepped IG unit with an incompatible silicone at the top in combination with a sealant depth that is too high. When this occurs the extender from the silicone migrates through the secondary sealant and washes out the primary sealant, resulting in a loss of functionality.
  • Incompatibility between weather sealant and secondary sealant. No backer rod and too much sealant applied (seal depth).

How can these problems be prevented?

These problems do not happen overnight and insulating glass producers and the window or facade builder play a significant role in their alleviation. There are a number of checks that should be incorporated prior to and during construction. The IG producer should:

  • Check compatibility of primary and secondary sealant.
  • Check compatibility with laminated glass.
  • Check compatibility with glass coatings.
  • Follow the application instructions, both in terms of preparation and climactic considerations.
  • Ensure correct storage and transport. The window and/or facade builder should check the following:
  • Compatibility with glazing materials.
  • Compatibility with setting blocks.
  • Compatibility with backer material.
  • Compatibility with other materials in contact.
  • Follow the application and glazing instructions. In addition, there are other guidelines which may help reduce the risk of incompatibility.
  • Use only well know systems, ideally from one supplier who has a product range that encompasses both glazing, silicone and weather sealant.
  • If possible, test glazing blocks or use inert plastics like PP or PE.
  • Ensure compatibility of glazing blocks with adhesive or use of hook blocks as a constructive alternative for fixing to the frame (ensure aerating and moisture pressure regulation)
  • Backer material. Ensure closed cell PE-cords (sealing depth)

The challenge of sealant compatibility combined with sealant performance is one that will not go away, in fact it will become more prominent as architectural, environmental and commercial demands become even more demanding. Recognising this need, sealant manufacturers continue to invest in research and development and installers and fabricators also have obligation to understand that compatibility matters now more than ever before.