We want to drop the ceiling in our dinning area to match the height of our new kitchen ceiling and add a tray detail in the dining area. The current ceiling in the dining area is 9’ high and it will be dropped to 8’. The combined length of the new 8’ ceilings, kitchen and dinning area, will be 24’. It is very important that the ceiling is flat and straight and resistant to sagging. The dining area portion of the ceiling will be 9.27’ (111-1/4”) wide by 15.89’ (190-3/4”) long and I will use 2x6 on 16” centers to span the width. Three of the sides of the new ceiling will be framed by attaching 2x6 rim joists to the existing wall studs and 4x12 beam. The new joists spanning the dining area will attach to the new rim joist on one wall with metal hangars. How to support the opposing joist ends is not clear.

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There are six 2x12’s above where the end of the new 8’ ceiling will abut the existing 9’ ceiling in the living room. I could not find any examples in framing books on how to support this section of the ceiling. I was considering doing the following, but I imagine the code would require some type of metal connector to attach the 2x6 ceiling joists to the 2x4 attached to the existing 2x12 floor joist above. I am hoping someone here will be able to help with the best method of framing this side of the ceiling.

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The tray opening will be framed with 2x6 double header joist and double trimmer joist. The depth of the tray will be 11” and the top of the tray opening perimeter would be defined by 2x4’s attached to the existing 2x12’s above. The sides would consist of 3/4” plywood attached between the 2x6 framed tray opening and the 2x4’s attached to the 2x12’s above.

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Thanks for taking the time to read my post and consider my questions. Comments and suggestions appreciated.

 

I don't like the idea of attaching rim joists to the existing studs. That's a lot of weight to add to them. Headers should be built on each end of the new 2x6s that you plan to install. Yes, you will lose a few inches of space but it guarantees a solid structure.

Of course, a hung ceiling with tiles is another choice.

 

Last tray ceiling I built post construction didn't have ceiling nor wall covering so it was rather simple. I just made modified triangle-to-flat 2x12's and made them long so I could attach them directly to the flat of the stud and to ceiling structure. I attached vertical 2x4's to the ceiling members to overlay the side of the 2x12 for strength. You could possibly use mending plates if they all lined up. Making them identical eased the installation process. With your ceiling and wall covering installed you have a little of a handicap.

 

Thanks for the suggestions. We were going to put a tray ceiling in the kitchen, but that would have severely impaired the air handling capacity of the range hood because of the long vent run and extra elbows. In addition, the curved soffit with breakfast bar would have intruded too far into the dinning area so we though we would extend the kitchen ceiling height into the dining area and define the dining area with a tray ceiling. We decided to go with a straight soffit across the room and leave the dinning room ceiling height at 9’.

 

I'm not enough of an expert in this area to say exactly what you need to do, but have you considered using steel studs? All you need to do is support the weight of you tray ceiling with this stuff. It will also be far straighter and lighter than wood. I see Mike Holmes use that a lot for soffits.