flush fin window installation in aluminum frame - plus a sill?
Hey guys/gals. So I moved in 18 months ago in a 1954 stucco home in southern cali. the windows are original aluminum frames (the crank style windows), single pane and the glass is starting to crack. My original plan was to simply remove the glazing & pant and refinish everything, but the windows themselves are too frail and I am looking to simply put in newer windows.
The wife has given me the "OK" to buy one window and try a replacement to see how it works, and if so, one window at a time. we only have 8. My internet research has uncovered that I can pull out the old windows, keep the original aluminum frame, buy flush fin replacement windows and install with the old aluminum frame. The overall steps seem to be (summarized) to add a small piece of wood to allow the new window to sit on inside of the frame, use an adhesive around the frame to adhere to the window (keeping aware of weep holes), use shims to ensure plum, use foam on the inside to insulate, finish with caulk sealant on the outside of the window trim and house facade, and cover inside with trim.
The only thing I am having trouble understanding is that our old windows have sills. A flush fin windows trim would hit the seal and not seat correctly. What are my options? my initial thoughts are use a chisel to remove the interferring wood from the sill? Other than that, i'm not sure.
Let me know if you have any knowledge in this area or if you need more info.