My neighbors house and mine are identical except for the roofs. He recently had all his aluminum windows replaced with Jeld Wen Vinyl ones. On both our houses the old aluminum extrusions drip edges extend past the stucco by about half an inch. The installer doing his just slapped the replacement windows in over the existing windows, making them stick out half an inch farther than one would expect and they stuck a half inch of caulking in there to fill up the space. I happened to see a Jeld Wen rep knocking on his door so I asked him about that and he said the protruding aluminum should have been cut off by the installers, plus said the bottom of the window shouldn't have been caulked. The place I bought my Certainteed vinyl windows from also said I probably should grind the protruding aluminum off too.

I went and bought a hand grinder and some abrasive cutting wheels and cut the protrusions off one of my windows already but it was a lot of work. My question, would most installers do the job right and cut off the protruding aluminum or would the just stick the windows in and fill in the big gap with caulking. Also I read I should fill in the channels in the aluminum frame with wood strips to make a solid surface for installing the windows. The only 5/8 inch square lumber I could find was some furniture grade poplar that cost $1.98 for three feet so this will be expensive to do. Would a pro do this? I don't think the cut rate outfit that installed my neighbors windows did this as I was watching them and I didn't see them using any wood strip fillers. I also didn't even see my neighbors installers stick a level on the aluminum frame to see if it was square. The window I am doing now isn't square so I will use shims and caulking under the wood filler strips to square them up. Do most pros bother with squaring the window?