We installed a bay window in our family room about three yrs. ago. Before the window we had a patio door. The door had a leak on the left side.
We assumed the previous owner didn't install it properly. Now, our window leaks when it rains or snow is melting. The strange thing about this is it doesn't happen all the time. We think there might be a bigger problem possibly with the vinyl siding outside. There is a lot of mildew on the siding above the window. We are not sure what to do about the leak. Someone told us to start pulling off the siding, but we have no idea what or where to begin.