I'm planning to replace the tile window stool below this window with a piece of quartz countertop. In this picture, I have already removed part of the thick tan tile the stool is made of.
It looks like the window might be sitting on top of the tile, in which case removing 100% of the tile will remove support from underneath the window. Is the window actually supported by the tile? How can I prepare the area for a new window stool without compromising the installation of the window?