Hi Sonia.

I've built many trey and coffered ceilings in my career and the formula is... whatever is aesthetically appealing. I know that's not much help but if you gave us some photos of the space including any crown and trim details we could probably be of more help.

Are you putting lighting inside the trey? that also dictates the dimensions.

Just based on your measurements I would guess you're coming down 8 to 12 inches; in which case I would say you're trey should project 12 to 16 inches from the face of wall. You don't want the trey to dominate the ceiling space, only to accent it.

I always do rectangular treys with the longer dimension on the horizontal plane. But again, need to see the crown heights and projections for both wall to trey and trey to ceiling.

I wish I could give that but I'm in the design stage with the builder, not construction yet. That's why it's so difficult for me as I'm terrible at visualizing things that aren't front and center to me. I want to hang a large (26" diameter) light fixture in the tray. You indicated I should only come 12 to 16 inches from the face of the wall if the tray was 8 to 12 inches. The builder recommended a 9 inch deep tray that would be 18 inches from the wall. Is that too much?

I would think that 9" deep would work, but the 18" seems a little much. That would leave you with an 8X12 foot upper ceiling.

Sonia, here is something to give you an idea with the various 18" wide tray ceiling heights for a room with a 9' ceiling

12"

10"

8"

6"

Best of luck

Thank you GN Builders. I now see how the 12" one really brings the ceiling down and is very dominant, even the 10" does that. In my mind, those should be used were the ceiling is higher than 9'. I'm liking the 8" or 6". I think if I use the 8" I might make it only 14" or 16" instead of 18".

Sonia are you saying that the tray for the ceiling is being accomplished by building down the perimeter ceiling (everything except in the tray area) rather than by raising up the center tray section (which would leave the outside perimeter at 9' from floor and tray at a higher height like 10')? We generally don't see it done by lowering the perimeter of the ceiling - particularly in new construction. I could understand it more if it was a remodel and there were structural constraints.

I'm starting out with a 9' ceiling and lowering it maybe 6 to 8 inches. To go to a 10' ceiling jumps the price dramatically (where I am).

The information here is very helpful. I would like to get some help for my project as well. I have a vaulted ceiling in the master bedroom. The room is 15' x 25'. I would like to bring the ceiling down make a tray ceiling. The problem is that if I need to get a 9 ft ceiling, the try has to be 25" wide and 18" deep. Is there any suggestion on how I should scale the tray or there might be a better way to do to get a 9' ceiling. Thanks in advance, Weibin