Proper installation of crown molding can be a mystery to the first timer. The following question was asked by Jason Falejczyk, and the responses he received tell a lot about how the process is done.
Jason Falejczyk asked:
I just called my hardwood dealer explaining how the addition of two angles are more than 90 degrees. They said it's supposed to be back beveled a little in order to make for a tight fit. I understand back beveling for that purpose, but I'm a little concerned about when it wraps around an outside corner: will it show a gap. Oh well, only one way to find out.
Steve, Furniture Crafters, Dallas, TX
Jason, you should be able to place the crown molding between the fence and the table just like between the wall and ceiling except upside down. Pretend the table is the ceiling and the fence is the wall.Now when you make a 45 cut it will be oriented properly.
Actually, most wall/ceiling junctures run somewhere around 92* to 95* on the really bad ones today. Stick a framing square up and and check the corner at a number of places around the perimeter of the room. What happens is that even if the framing of the house is square, (pretty likely) the drywall finishers tape the corner, then bury the tape, then feather this out into the rest of the surface. So in the corner, the mud may be 3/16" (or even 1/2") thick, feathered both ways to nothing in 8" to 12", leaving greater than a true right angle. Yes, I"ve worked in lots of expensive places with true lathe and plaster work, and the work is usually more "craftsman" like, but not always any squarer.
If your walls and ceiling are dead square, then just choose one back surface of the molding and adjust the angle with a jack plane. 32 ft might take you 15 minutes, including time to think of a stable approach.
It is poor form (shoddy workmanship) to miter inside corners, they should always be coped. It's easier, it allows for slight wood movement, and it allows you to perfectly match the outside corners by allowing some slight leeway in the length of the piece that will be covered by the cope.
I usually cut any cope cut first, and the other end last, That way if the cope goes really wrong, it can be recut before the stick is too short. It is seldom necessary to make a cope cut on both ends of a molding if you have planned the room right. When it does happen, it is usually the last piece, and there will have been ample time to figure how the ceiling rolls, so to speak, so you can guess pretty well where to compensate. This brings to mind, of course, Always do your longest runs first; hopefully your closing pieces will be short ones and you will have three or even four pieces of short end to get it right without actually wasting anything.
When coping molding corners, I plan it so that, when entering the room (or from the most frequent viewing point) the viewer looks along the coped molding, and into the solid member behind it. In other words, If you look along the first piece put up, you are looking into the crevice and will notice any irregularities. But if you are sighting along the second member installed, you hardly notice the joint. So I plan the cutting of the coped joints to be most pleasing to the eye from the most frequent view point (usually the point of entry into the room).