Block frame (box unit) installation involves replacing only the window’s existing sash and leaving the window frame intact. … Full frame installation involves completely removing the existing window and replacing it with a new one.

What is blocked frame?

Block frame (box unit) installation involves replacing only the window’s existing sash and leaving the window frame intact. … Full frame installation involves completely removing the existing window and replacing it with a new one.

How do you measure a window for a block frame?

Holding the tape measure taut, measure diagonally from the inside of the upper left corner of the window (where the horizontal and vertical trim boards meet) to the inside of the lower right corner (where the horizontal and vertical trim boards meet) and record the measurement.