Temperature differences
Thermal movements occur in practically every joint. In the case of wood as a frame material, however, the thermal movements are so small in comparison to the moisture-related movements that they can be neglected.
In the case of dark-coloured façade components made of aluminium or plastic, surface temperatures of over 80 °C occur on the south side. This results in changes in length of up to 3 mm per running metre, depending on the material composition. Therefore, the temperature changes of the profiles that occur in the installed state due to the external climate are decisive. These movements must be absorbed by the sealing materials used.
Taking into account research results on the actual length movements that occur, the following temperature-related changes in the connection joint are to be assumed:
| Window profile materials | ε in mm/m |
| PVC hard (white) | 1,6 |
| PVC hard (coloured) and PMMA coloured extruded | 2,4 |
| Thermally insulated aluminium composite profile (light) | 1,3 |
| Thermally insulated aluminium composite profile (dark) | 1,2 |