The Shimflex can expand to over 1 inch.
No, the Shimflex system can also be used when replacing existing windows.
Yes, it is possible to do so although we recommend using the Spacer which is less expensive.
In the case of heavy windows or doors, if you wish to use a Shimflex to adjust the height we recommend removing the #8 – 4“ screw and replacing it with a #10 – 4“ screw.
Yes, both Shimflex and Spacer allow a better spread of the insulation foam.