Bonnie What part of the country do you live in? If you are in a cold climate plan on the wood expanding and possibly closing the gaps when it gets warm. Caulking has its purpose but there will be ongoing maintenance with any caulked area as things expand and contract the caulk will eventually crack too.

Bonnie Post pictures if you can.

Sarah Jorgensen Hi Bonnie, We live in Washington State so it's pretty moist all year round, but we do get all four season...

jacksonwright If you can stick a finger in the gap I would fix it if it were smaller I would caulk it

feeny The seasonal caulking crack is an inescapable phenomenon where we live (Ohio). So in winter it looks like all of our kitchen cabinet moldings and crown moldings (which are caulked and painted), especially in an addition we built onto our older house, have cracks next to the ceiling, where they are pulling away. Then as summer approaches all the cracks disappear and everything looks like new again. Since our kitchen was renovated in the summer we were a bit freaked out the first winter this happened. Now we are used to it.

carolannr Is the crown molding not painted? Even pre-finished moldings are usually painted. These little gaps are typical when you have the crown flush to the ceiling - ceilings are not as flat as moldings even in brand new homes. Caulking is the typical way to handle this, unless the gap is so big you have to add additional shoe or a pc of quarter round molding to the top. If you live in the parts of the country where wood expansion is a problem, caulk usually works best because it is flexible.

Deborah Butler, Brickwood Builders This is always one of the issues with painted cabinetry - against the ceiling and the walls. I think your contractor is correct in that once you caulk it, you will see the difference in color and more painting will need to be done. If everything is not the same white, you may want to have the ceiling painted the same white as the cabinets. You will see the expansion and contraction that feeny and others pointed out as seasons change.

Eidos Designstudio.com take a small peice of veneer with white glue on both side and fill the gap. The veneer can be sanded to make it thinner where the gap is narrower .Sand when it is dry and paint over top.

Sean Crowley Custom Carpentry In my experience as a custom carpenter, I do whatever it takes to eliminate visible gaps in all moulding to drywall/plaster applications. Painted crown moulding (very often white) installed against a white ceiling is always the most difficult installation, but probably the most common. More often than not, ceilings will have "bumps" (convex) or "dips" (concave). Often I can shave a moulding (most profies) with a small block plane to accomodate small bumps in the ceiling but usually not more than 1/8''(depending on the size and profile of the molding). Dips in the ceiling are treated after the moulding is installed. To do this I "float" joint compound over the dips in the ceiling. Essentially replastering the ceiling to achieve a flat plane.( Wall irregularities can be treated the same). This plastering need only be done in areas where the gaps exeed 1/8'' or so, and usually feathered in to the existing ceiling within 6''-8''. This feathering can often be done in one coat (depending on th size of the dip) then sanded and primed. At this point we want any moilding to wall/ ceiling joint to be less than 1/8''. This small joint is then caulked very neatly, taking care not to caulk over the mouldings. Of course any patches will need to be painted, so we often give the ceiling its final coat of paint after the moulding. As far as seasonal movement is concered, I have found that MDF moulding moves less than wood. Looking at my crown moulding now (dry, winter) I can,t see any visible separation.

Bonnie Sean... you sound like an awesome craftsmen!

Sean Crowley Custom Carpentry Thanks Bonnie. I like to think so.

Sarah Jorgensen Here's some photos, I think we are going to either caulk or some other method to fill the small gaps...

Laura Bohn Design Associates Crow molding, leave a 1"space if the ceiling is not level it won' t show,and the space makes the molding stronger looking. If it is already installed take it out it will never look right.