What kind of home are you building where that would even be appropriate? And what is your water management strategy?

We are trimming new windows and a new entry door on an older home. This is meant to be classic trim (I’m not sure I understand your question about where this would be appropriate). Regarding water management, the house has gutters.

I need to see the house to understand where this is going. Post a pic here in a comment DO NOT start another post . We need context , I have rarely seen this type of trim on the exterior of windows .Is this what you are doing ?

Yes

Here’s a photo of the house. A contractor partially installed crown on the windows but decided he didn’t want to do that kind of work anymore, and moved on before finishing. The crown is up without returns and without any cap that closes the gap between the top of the crown and the house. I’m trying to figure out the best way to proceed — find someone to install returns and caps, or start over with solid crown.

You need a finish carpenter and cellular PVC material. Like Azek. https://azekexteriors.com/solutions/window-surrounds

Photos:

Planning to use Versatex.

It looks like everything (casing/trim) is installed on top of the siding.

You would normally have flashing that caps the crown and extends under the siding.

That’s good to know. Thank you!

Recipe for big time rot in the walls without the right flashing.

" Planning to use Versatex. "

You will be very limited in your choices then. Also PPE and Lomo are correct that siding/trim configuration with the lack of flashing and water mitigation is a big mess in the waiting.

Yep you will have bigger problems than choosing how to do the crown.

Thank you. Any thoughts on the best way to find the appropriate person to set things right? Also, there may be appropriate flashing in place (the past contractor may started by doing the right thing even though he did not finish), but I’ll need to look into it to know for sure.