My question is very similar to "How can I fit a door in a frame that is too small?" except my house is made of concrete block. I bought a used patio French door to replace my sliding door. The sliding door measured 71 1/2 x 80. The French doors measured the same. After taking out the frame for the sliders, I need at least 1/2 inch on the top and sides. Help!
It depends on the construction of the door, but if it's a wood door, you should be able to take off 1/4" from the top and bottom without any problem.