It's spring and those little (and not so little) outside projects are rearing their heads again. I've been procrastinating this one for 2-3 years, but can't any longer. Our home has two kinda South-West facing replacement windows, probably about 12 years old. I chose to keep wood framed windows in line with the rest of the 45 year old house. Of all of the windows, all the same brand, but bought at different times (cost containment) these two have rotted sills. I'll have to pull the frames to make my repairs but have never made my own sills. Any advice? Best wood? Treated? Oak/Maple or....? Special tools? Interestingly, we still have a couple of the original windows in the dining room and they are as solid as the day they were installed by the builder even though they were never repainted until we moved in 18 years ago.