August 2021


Our range now features new XPS forms designed for use as thermal insulation beneath aluminium external window sills.

With their outstanding thermal insulation values, our ISO-TOP WINDOW SILL FORMS are perfect for insulating the window sill connection area in new residential buildings, single-family homes, nearly zero-energy buildings and passive houses and when installing energy conservation measures in existing buildings.


ISO-TOP WINDOW SILL FORMS are made from XPS polystyrene and are installed immediately beneath the window sill. This is always a critical area with respect to heat retention. The very low thermal conductivity of these new insulating profiles can be applied effectively to optimise thermal bridging in the design.


These window sill forms are not only suitable for thermal insulation, however. They are also ideal as a highly compression-resistant substructure for window sills made from aluminium or mineral materials.


The forms also have a positive effect on the temperature factor fRSi and increase the internal window breast temperature. This helps to reduce moisture and mould on the internal window breast surface that connects to the window elements.


ISO-TOP WINDOW SILL FORMS can also act as a second sealing level if they are glued all round to the wall and window profile in combination with our MS polymer ISO-TOP FACADE SEAL – an ideal option for sealing the lower connection. The forms can also be combined as required with the other products from our ISO³-WINDOW SEALING SYSTEM and ISO³-EWI SEALING SYSTEM.


We also supply solutions tailored for a wide range of geometries on site. There are six different basic variants available in price groups which are classified by shape. These can be cut to length on site using a mitre saw or hand saw.


The ISO-TOP WINDOW SILL FORMS also comply with the requirements of the EU Energy Performance of Buildings Directive, the German Building Energy Act (GEG) and the principles of the RAL "Installation guide”.


>> Click here for our ISO-TOP WINDOW SILL FORMS

back to overview