How to do uPVC Windows Measurements ? I will show you how to measure your uPVC window , Generally we need two measurements , such as width and the height , all should be in mm . Now let reach near the window opening to find the width , use measurement tape in millimeter from left side wall to rt side and record/ write in a note book , then measure the height from top to bottom , Please record/write the measurement in a note book first always first is the width then the height . While giving for fabrication , can minus 1 mm . Always check the windows are properly silicone through out the perimeter along side the wall . Even after the silicone id dried please spill little water out side and check the water is not sipping towards the home side . Please check out in Youtube . Waiting For the Comments . To take measurements for windows at home, you will need a tape measure and a notepad or measuring app to record the measurements. Here is a step-by-step guide on how to take the measurements...