My house was built in 1984 there are no window sills! On the interior of the house the window openings are finished with sheetrock all the way around so there's technically a sheetrock sill I suppose. Over the years the old windows leaked apparently and that sheetrock is damaged and looks awful. The windows have since been replaced but I'd like to retrofit with sills. I hope I'm using the right terms here! So I'm looking for advice on how to do this. Is it possible to just remove the existing sheetrock layer and cut sills to fit, etc? Would that be the right way to go? Attached is a pic of what is currently there. Is there a better way to improve this? I could probably patch the cracks, etc and paint but then there's the texture matching issue which I don't want to mess with! HATE the texture on my walls but that's another topic altogether. What is the consensus on using pvc window sills versus wood? I have twin hung (?) and oversized windows so not sure if I could even find pre-cut pieces that would work.