I have a crown molding question.
I have been in my house now for many years and nearly every winter I get gaps between the crown molding and the ceiling. This does not happen everywhere but only in a few locations. Is this just what I have to put up with because of seasonal changes (I live in Massachusetts) or was the molding installed incorrectly? I have tried caulking the gap and it is OK for a while but the onset of the next winter season opens it up again. Also, I have a whole house humidifier but even with that it is drier in the winter.
If it is improper installation what would I need to do to install it so this does not happen?
Thanks for any advice.
John
Replies
JOHN,
I have a similar situation in my house and I've come to the conclusion that it has something to do with snow loading the roof and the different framing members flexing . Your situation may be different though. Only a guess .
DAVE
Dave,
I never thought of that. The problem does only occur with the crown molding on the second floor. I have never had this issue with the molding on the first floor. If snow loading is the cause I am guessing that this would be very difficult to fix.
John
Others will probably chime in with more details, but it sounds like your rafters are heaving. It's not uncommon for the middle of your rafters to move up and down depending on the season. This lifts the ceiling up away from the wall. Are the gaps mainly along walls in the center of the house ( or under a ridge line ) ?
To avoid this, the crown should be attached to the ceiling only. This way when the ceiling goes up and down, the crown goes up and down with it, thus eliminating the gap. This doesn't sound like an easy trick though.
Yes, the worst area is directly under the ridgeline in a second floor room.
The roof construction is prefab trusses rather than stick built. I wonder if there is any way to strenthen this.
Rehang the trim as mentioned above. Make trim blocking from 3/4" ply ripped and nailed up into an "ell". Make sure it will fit behind the crown mold. Fasten it up into the ceiling, into joists and occasional ez-anchors, sub-floor adhesive helps(only on the ceiling). Insure that the vertical leg of the ell abuts the ceiling with the horizontal abutting the vertical. Rehang the trim using nails just long enough to penetrate the blocking. Now the trim will slide up and down like a sleeve. If the wall is wavy don't caulk to the wall, as the movement will tear the caulk and leave it exposed and hanging when the ceiling heaves. You could float the wall straight at the top foot or so with some topping compound and a long straightedge but then you'd have to repaint.
Another option is to rehang the trim with a "soffit". This could just be a stip of 3/4" ply nailed to the ceiling flush with the top edge of the crown. Next hang the crown with blocking but all fastened to the walls. Finish of with a piece of flatstock or even bed mold that could either reveal half of the crown's top edge or hang below as a shadow line. This soffit concept can be anywhere from a simple 1" flat board to a whole other run of crown, one fastened to the ceiling with one fastened to the wall around a larger boxed soffit. The design possibilities are endless.
Or you could just live with the shadow line as a working example that a home is indeed a "living" structure...
Thanks for the detailed reply. I guess there is no easy fix. If I get real ambitious I will try one of the methods you outlined. Then again, I may just live with it a while longer.Thanks again,John
You have a problem called 'truss uplift", common in winter. Crown is used so you don't have to see the SR joint cracking. The shadow line is preferable than jagged cracks
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
The problem is not installation, it's seasonal changes. The only way to control it is to keep the humidity at a constant level throughout the year. This is very difficult, especially in a cold climate. Wood moves across it's width the most, softwoods more than hardwoods. The wider the piece the more apt it is to shrink and swell. This is a problem cabinet and furniture makers face all the time. Heat rises, so, crown moldings can get effected more than other trim in the house.
Your humidifier is probably not able to supply the necessary moisture for your square footage. You need to pump at least 5 gallons of water per day for every 1000 SF. Even with this much water, lack of proper vapor barriers in the outside walls, air leaks, inadequate insulation can all dissipate that added moisture. Too much humidity can also cause problems. Generally a humidity level of 35%-40% is ideal, not only for your woodwork but for health and comfort.
Beat it to fit / Paint it to match