Hello, I am remodling my bathroom and wanted to replace the bathroom window (in the shower wall) with a glass block window. I have all the plaster walls taken out to the studs so I can see the frame that holds the window in. My first problem is how do I measure the window opening? The house is brick and the sill on the outside is at an angle up to the window so will I have to take out the window to measure for a correct size? If anyone knows of a good tut or images please post. My second problem is how much gap should I have around the edges for the morter when I order my window?