Crown Molding - Cracking at the seams

I have a fairly new house (3.5 years old) - and every Winter that I have lived in it, the crown molding throughout the house starts to get gaps formed either in between the crown molding and the wall, or the crown molding and the ceiling. Some of the gaps you could put about 3 or 4 credit cards in for the width. What makes these gaps even uglier is that it takes the PAINT off the ceiling...and leaves uneven looking gaps.
This happened for 3 straight winters. The BUILDER has come to the house on 2 different occasions (during the spring) and has put a white caulk in the gaps and fixed the paint job.
Does everyone with crown molding have this problem? Is there a permanent solution to fix? Any other solutions?
Thanks.....
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
i notice those separations in the crown molding ONLY in the winter, so i am sure its humidity (lack of) related.
--
read and post daily, it works!
rosie

"Hell they won't lie to me/ Not on my own damn TV/ But how much is a
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Wood moves from changes in humidity. It is mostly along the width rather than the length of the boards.
You can't prevent the movement, but you can add humidity that will slow or stop it. Get a humidifier and you will breath better, sleep better, as well as keep your house and furniture in better condition. Ed
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
A good whole house humidifier would be the best solution.
However there are others. One is to add a scarf joint a short distance from the corner. The inside of the joint is painted before it is assembled. Generally this will cause the gap to occur at the scarf which will not be very visible.
An elastic caulk along with cutting the paint line with the ceiling and wall (use a sharp knife) will help.
--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Years ago, I had the task of doing a study on an entire high-end development where this was occurring. Relatively new in the houses' lives, wide gaps were appearing at the baseboard molding. I went through the crawl spaces & pored over the blueprints looking for any structural problem behind the gaps. Everything checked out. It was a mystery.
The only clue that surfaced in the investigation was that the housing development had started, then stopped for a period of several months while some financing issues were resolved. In that time, the houses sat partially finished, exposed to the weather. Our theory was that the floor & ceiling joists had absorbed higher than normal levels of moisture during this exposure. A follow-up inspection with a moisture meter backed up that theory. As the framing dried over time to normal levels, the thickness of the ceiling & floor joists shrunk, resulting in the strange gaps.
In my case, the problem was sufficiently documented among many houses to place some liability on the builder for the cost of the repairs. If you're in a development, it might be worth your while to see if your neighbors are having a similar problem.
Joe F.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The short answer as to why this is happening is that the quality of the materials is being lowered, and the knowledge of how to use materials to accommodate dimensional changes has been all but lost.
Problems like you describe are more common in newer construction because of the use of "cheaper" lumber. Lumber doesn't change dimension in the direction of the height of the tree much as moisture content changes. It does however change dimension in the direction perpendicular to the height of the tree.
There are two basic ways of cutting lumber, flat or tangential sawing (looking at the end of the board the growth rings will be somewhat parallel to the width of the board), and quarter or radial sawing (looking at the end of the board the growth rings run parallel to the thickness of the board.) Quarter sawing yields preferable lumber but typically only accounts for about 20% of the lumber sawed today. The remaining 80% of less desirable lumber is flat sawn.
Quarter sawed pine will change dimension with seasonal moisture content changes by perhaps 3% to 4%. Flat sawn pine may move as much as 7+%.
If your flat sawn crown molding is anchored along one edge as the seasonal moisture content changes the other edge may move by as much as 7%. This is about 1/4" over 4". Enough to do what you are describing. Mounting the molding so that it moves relative to the center rather than anchoring at an edge will help. Painting all sides (backside painting) slows the change in moisture, using quarter sawn lumber is desirable. Old growth lumber changed dimension less with moisture than the currently available fast growth lumber.
Another approach is to use PVC extruded crown moldings of the sort that Marley Molding (Bristol, VA) used to sell to Home Depot.
RB
Chris Hagler wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
All good answers.....and I think that a combination of humidity and quality of lumber is at fault. If it gets worse throughout the years, I think the best way is to replace it with the non-wood crown molding - surely that stuff doesn't move as much as lumber does.
Thanks all...
I have a fairly new house (3.5 years old) - and every Winter that I have lived in it, the crown molding throughout the house starts to get gaps formed either in between the crown molding and the wall, or the crown molding and the ceiling. Some of the gaps you could put about 3 or 4 credit cards in for the width. What makes these gaps even uglier is that it takes the PAINT off the ceiling...and leaves uneven looking gaps.
This happened for 3 straight winters. The BUILDER has come to the house on 2 different occasions (during the spring) and has put a white caulk in the gaps and fixed the paint job.
Does everyone with crown molding have this problem? Is there a permanent solution to fix? Any other solutions?
Thanks.....
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The only problem with that is the lumber under it can still move.
--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.