I'm a novice do-it-yourselfer. I'm looking at this new project that has been discovered. Long story short, house had no gutters for 50 years. I fitted gutters last year.

I'm trying to tackle water damage spots around the house and I'm wondering what people think would be the best solution here. My initial thought was "just a little" rot

that could be tackled with some epoxy and painted...but the more I probed, the more damage I found. The outer sill is radiused, basically two pieces joined in the middle.

I'd rather not just band aid it. I just don't know what I'm getting into, and don't want  to blindly wade into this project with a sawzall. Any thoughts on the complexity of this?

Could this be accomplished by a DIY type? Should I hire it out? Can anyone with experience in carpentry give me a ballpark of what I could expect to pay to get this repaired?

Thanks.

Appears to have been cut from a wider piece to make the curve.

The 'short grain' at the end allows water penetration and sets it up for rot.

Making a new piece would be the best course.
Installing it can be a real PITA though.

If you do the same thing treat the wood with Minwax Wood Hardener completely and thoroughly.
Soak the wood in the stuff.

It will penetrate and leave acrylic resin behind hardening the wood.

It also fills in the gaps between the cellulose fibers so water cannot penetrate.

I would build a new sill out of a planned down piece of 2x12 cedar, and rout the face profile on my router table. A multi tool make quick work of cutting the old sill out. I would also re-skin the face of the lower sash.

ETA: I'd be around $600 to do the repairs on that. That would be the sill, lower sash, glazing and coming back to paint.

Where would you start? Just plunge the Fein into the front of the sill? Or are you talking about running the blade in parallel with the sill and cut any nails. I really can't visualize how this thing is all attached. It would be nice if I could just cut a

replacement and slide it into place, but I know this is probably built in like some sort of a Jenga puzzle. How much of the window would need to be disassembled? I don't mind paying for this fix, but my problem is that I want it done by a

craftsman and I really don't know how to find them these days. My priorities are durability of repair, quality of material, and continuity of architectural style. Does this look like a pretty simple repair for a regular carpenter or do I need to find

someone with specific qualifications...if thats even a thing?

For a sill like the one you pictured, a wood rot carpenter can easily knock it out in no time. A quality painter in your area can point you in the right direction. I have a trailer full of tools that I use to replicate the profile of the sill, tools like that for a homeowner would be a healthy investment.