Revisions log for question
Is there a dimensional grid for windows?

We are in the process of revising our planning. We want to reduce the height of a window and move it a bit further down. Now our house manufacturer has said that we should only make the changes in a 12.5cm grid. So for both the window size and the shift. Does anyone know why this is? Are the bricks in the dimension and it should not be cut or how could it be explained?

• windows
• dimensional grid