gaps on crown molding
#1
01-09-12, 07:57 AM
gaps on crown molding
Anyone have any idea on the following?
I recently finished putting in a tray ceiling, replete with crown molding within the recessed part and below it, and everything was fine and dandy. Then a month later I had issues with the concrete floor in the room in terms of it being too uneven for the wood floor I wanted to put down, so I had to do a lot of grinding. Even though I had a vac unit I was still generating a lot of dust, so i opened up the windows and turned the AC on at a low temp. to keep air pressure in the house forcing out the dust. During the half day I was doing this the temp. in the house dropped from its regular winter temp. of 74 down to 66. As I finished up for the day I glanced up, and saw that all my new and beautiful crown molding had opened up at most of the join areas! Oddly though, it was only in the room with the tray ceiling - all the other crown molding I've installed in other parts of the house is fine, though it was from a different batch that sat around the house for months.
Is it possible I got a batch with high moisture or something? As I said, it's been up for over a month, so one would think if there were any moisture issues it would have already shown by now.
Back to the drawing board. After all that work to get a nice finish that masked the joins, now I have to go over it again!
I recently finished putting in a tray ceiling, replete with crown molding within the recessed part and below it, and everything was fine and dandy. Then a month later I had issues with the concrete floor in the room in terms of it being too uneven for the wood floor I wanted to put down, so I had to do a lot of grinding. Even though I had a vac unit I was still generating a lot of dust, so i opened up the windows and turned the AC on at a low temp. to keep air pressure in the house forcing out the dust. During the half day I was doing this the temp. in the house dropped from its regular winter temp. of 74 down to 66. As I finished up for the day I glanced up, and saw that all my new and beautiful crown molding had opened up at most of the join areas! Oddly though, it was only in the room with the tray ceiling - all the other crown molding I've installed in other parts of the house is fine, though it was from a different batch that sat around the house for months.
Is it possible I got a batch with high moisture or something? As I said, it's been up for over a month, so one would think if there were any moisture issues it would have already shown by now.
Back to the drawing board. After all that work to get a nice finish that masked the joins, now I have to go over it again!
#2
01-09-12, 08:17 AM
Group Moderator
Unfortunately, I've seen it happen. With wood molding its moisture and with foam moldings they seem to shrink over time. For foam molding I cut them long and bow them to get into position. Wood molding is a real pain. I have not found a good way to deal with wood expanding and contracting other than trying to put it up when it's dry which is a real problem with new construction in the humid summer months and the house's AC is off. Cold dry winter air or the AC dries them out and cracks appear. I've been caulking them which works well if the molding is white and you use white caulk especially if the caulk stays flexible. Plain painters caulk seems to pull away after a couple years showing a crack again.
#3
01-09-12, 09:25 AM
Polyurethane caulk seems works best on crown molding, especially if there is a lot of humidity changes.
How long has the window been closed and the room back to normal temps and humidity?
How long has the window been closed and the room back to normal temps and humidity?
#4
01-09-12, 09:44 AM
Hi again,
The temps have been back to normal for a few days now, and even though the gaps have closed again somewhat they're still in evidence. As it happened mainly on the mid-point joins rather than the corners it's not too hard a fix, but a couple of the corners did also open up, which is tedious - I hate fixing inside corners - so time-consuming and fiddly!
Thanks for the feedback. And by the way, these are the pre-painted MDF variety available in pro-packs from the big box stores. That's why it surprised me somewhat - wood I would have expected to give some trouble, but not this stuff.
I'll also try the polyurethane caulk next time round.
The temps have been back to normal for a few days now, and even though the gaps have closed again somewhat they're still in evidence. As it happened mainly on the mid-point joins rather than the corners it's not too hard a fix, but a couple of the corners did also open up, which is tedious - I hate fixing inside corners - so time-consuming and fiddly!
Thanks for the feedback. And by the way, these are the pre-painted MDF variety available in pro-packs from the big box stores. That's why it surprised me somewhat - wood I would have expected to give some trouble, but not this stuff.
I'll also try the polyurethane caulk next time round.
