Here is a photo of one of the homes my builder recently did:

Logan - Twin Bridges · More Info

When the builder asked if you wanted casing under the window sill, did he mean the apron (the flat "trim" that goes directly below the stool)? If so, yes, you'll want that!

Laundry Room · More Info

I've always found the rounded wall "corners" troubling in executing the baseboards. The neighbor's house has "corner" posts that square it off to meet the baseboards, but to me it makes it look like a fence

Wow! When I read "Exciting questions about window sills and drywall corners" it got me on the edge of my seat!

Ok, all seriousness aside, I agree with jannicone, the baseboard detail is the tough nut to crack there. Haven't seen one yet that looks right.

Trimtex is the main source for better drywall transitions and have used their base adapter, towards bottom of link, for better looking bullnose transitions. Nice to have final base width and floor thickness for proper placement. We have also made pie shaped (concave crust) pieces of wood to fit the gap which looked nice, but took some time. The worst look is the cover-up 45 degree cap molding.

Wood sills do not have to have an exposed square 90-degree edge. You can bull-nose them, with or without any casing below the sill piece.

I really, REALLY don't like rounded drywall corners.

rmverb -- why? Just a personal preference thing?

Doug, if you're still online -- do you think rounded corners (especially in my two drywall "niches" (piano wall, tv wall) would look "southwestern?" I'm going for modern-craftsman and am not always sure what that means. Ha! :)

Bullnosed(your term rounded) is not necessarily southwestern. Our kitchen cabinets were built in 1965 and have bullnosed corners. I just remodeled a hall bath with one bullnosed corner and wainscoting. It does not look southwestern.

Window sill treatment(stools/skirts/sill/apron/whatever) are the bottom trim on a window. The sill/stool is the flat horizontal portion people lay things on. The Skirt/apron(what the builder is calling casing) is the trim added under the sill/stool.

The stool is cut to fit the window corners. If you want to spend the extra money to have the stools cut to fit bullnosed corners, it can be done. That will be extra labor, however.

While I'm not personally a fan of bullnose corners, there are companies that make curved trim pieces that fit the corners.

Yes, it's just personal taste. I prefer squared off edges and cased openings.

arialvetica, I do agree with rmverb on the squared corners. If you're really going for a modern craftsman look, I would not do bullnose corners. I'm not a fan of them because they look dated to me and look like they best fit homes with rounded arches/doorways. We had to specify that we wanted squared corners on our house... bullnose is standard and we are the only house in the neighborhood that has done square and everyone on the builder's side keeps saying how nice it looks.

Funny, how drywall returns/sills around any windows on a high-end traditional home in my area are virtually unheard of. Even in basements.

I think it's a function of your personal aesthetic. I am not surprised that a lot of high end homes have cased windows and not drywall returns. So many are fans of the "quality" of a home being determined by how many pieces of crown you have...

Getting a good, crisp, square drywall return - even though it's minimalist - isn't easy. And it's valued by those who value a more modern aesthetic. It's been my experience that often the simpler / cleaner solution is more expensive than being able to hide less exacting work with trim and embellishments.

Right. It's the "modern" aesthetic. One drywall sub wouldn't do them without trim. We didnt use him. Ours ended up pretty sharp and mostly straight so it can be done.

True that sometimes what looks simple is more expensive.

Thanks everyone! I went with squared off corners--sent my final answer to the builder this morning. His observation is that square corners are "coming back," and that bullnose have been the trend the past few years. (In our area anyway.)

Arial, can we see your plan again? I wish there was a way to quickly find everyone's plans and finished homes.

cp -- this is where I posted the elevation drawings + main floorplan. I keep meaning to post some sort of a progress update somewhere, but life keeps interrupting my internet time! :) http://ths.gardenweb.com/discussions/3598813/we-fit-an-architect-into-our-budget-and-it-was-so-worth-it

With your plan, the square corners are DEFINITELY the best answer. :)

That's what i thought I remembered and I don't see it as craftsman but as a warm NW contemporary style. Definitely glad you'r not going with bendy walls or rounded corners or whatever you want to call them. LOL.

How far along are you? I want to see updates!

Oh and when you're all done, maybe as a favor, you'll show your first efforts, your new plan and your brand new house? Your house really shows how working with a good design person you can have everything you need and in a way you might not have originally thought of.

Drywall may fit the aesthetic. But it sure is delicate vs. wood. I've seen endless numbers of drywall sills sagging and stained where people have piled on flowerpots and assorted decorative doodads; and then there are the sweating windows often with metal frames in our cold climate and the damage they do.

I also agree with the above (which is one of the reasons we shall have no drywall in our new build!) Those corners sure look nice, but are hard to find someone that is REALLY good at getting them perfect, and they are fragile...

cp -- I do plan on doing that when we're all done. I've also been keeping a log of decisions I've had to make along the way, which I think will be really helpful to anyone who's doing something similar (100% custom build without any architect hand-holding).

Oh arial, I know once I get started it will be a huge help to me at least. Have you considered doing a simple wood trim on the inside of the windows so you don't get as worthy says those sagging, stained drywall sills? I know about them because this apartment we rent is full of them. Not to mention where the shades are that bang against the sides and dirty them. At least wood can be cleaned up

Definitely doing wood sills, but drywall returns on the other 3 surfaces. The cost to fully trim them out was really a zinger. Still undecided on apron or no apron. Leaning toward the apron.