Install window sill where none exist?

[missdoc77]

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.

 

[missdoc77]

Oops, pic didn't work - trying again.

 

[nealtw]

Yes wood or plastic would be a better way to have it. As this is finish carpentry work it will take some skill and tools. You will not find anything that is pre-cut to fit your windows.
A lot depends on how fancy you want to make them. [ame]http://www.youtube.com/watch?v=MC0JcD3triM[/ame]

 

[missdoc77]

Something fairly simple is my goal. Obviously ANYTHING will be an improvement! After picking away some of the cracked sheetrock mud and texture layer, it looks like the sheetrock itself is not damaged as I thought it would be. If I scrape away that mess and remove the corner bead (which I'm guessing will be necessary?), looks like I might be able to install a nice wood sill with some trim underneath and have a nice looking end result. Hopefully I can patch up the vertical corners and not have to redo all the way around which would require cutting down and reinstalling the blinds!

I've done some finish work before - baseboards, chair rails, door trim, stuff like that. But never a window sill. Is there anything in particular I need to know before digging into this??

 

[nealtw]

I would do the whole thing including sides, the drywall will be 1/2" thick so I think your blind would still fit if you use 1/2" material. If not I would remove enough of the side to slip the new sill in so if you want to do the sides and top at a later date you don't have to redo the sills. Just use a hacksaw to cut the side cornerbead at the right height.