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crown molding cracks

BruceT999 | Posted in Construction Techniques on December 21, 2006 07:02am

HO asked me if I could fix the cracks at joints of their crown molding. Painter filled the cracks with Bondo, of all things, and two months later cracks are back. What do you finish carps use to caulk the cracks of mitered corners?

I also saw a strange crack in mid run – FJ perhaps?

I doubt there is any way to fix the butt joint, is there?

Thanks,

BruceT
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Replies

  1. CAGIV | Dec 21, 2006 07:07am | #1

    what is causing the cracks?  Movement or just drying out?

    Team Logo

  2. bc | Dec 21, 2006 07:35am | #2

    your home's heater is causing the wood to dry out and shrink. fill the cracks in with pyutty and re-paint... no biggie...

    and ya the strange crack is the first time i have seen one like that...

    1. MSA1 | Dec 24, 2006 07:20am | #21

      That strange crack looks like the piece was broken somewhere along the line and he (the installer) tried to save it. The crack is too big to be a finger joint.

  3. Allon | Dec 21, 2006 08:35am | #3

    Generally we (finish carpenters) don't do the caulking, but when I do I use Big Stretch (as all best painters do).

    I probably wouldn't putty it because as it shrinks or stretches it will crack again.

    -Allon

    1. User avater
      PaulBinCT | Dec 21, 2006 03:55pm | #4

      From the way those corners are cracked, it looks to me like the fit was really bad to start with... if there's tons of any kind of putty in there I think it will crack again someday, just from poor bonding and different expansions. (IMHO of course)

      1. Allon | Dec 22, 2006 08:14am | #10

        So like I said, use Big Stretch or DAP Dynoflex (as recommended by other reader). They have more glue, so they will bond with the material and just stretch as much as needed, never cracking again.

  4. john_carroll | Dec 21, 2006 04:25pm | #5

    I had a similar problem once. In my case, though, the crack was along the top of the crown, where it met the ceiling. I called the 800 number on a tube of DAP caulk and the the guy told me to use DAP Dynoflex 230. It really stretches and can be painted. It solved my problem.

  5. User avater
    SamT | Dec 21, 2006 04:35pm | #6

    What the heck is going on???

    Only one of those follows the joint line?

    #3.jpg!?!?!?

    SamT

    Now if I could just remember that I am a businessman with a hammer and not a craftsman with a business....."anonymous". . .segundo  

    1. User avater
      PaulBinCT | Dec 21, 2006 04:36pm | #7

      My point exactly... (I bet #3 shows a piece that was cracked in rough handling during install and just showed up now due to drying or expansion stresses)

      Edited 12/21/2006 8:43 am ET by PaulBinCT

    2. User avater
      JDRHI | Dec 21, 2006 05:18pm | #8

      Yep......I don't think the problem is the joint at all. I think its the paint.

      Happy

      Holidays 

      1. FastEddie | Dec 21, 2006 05:20pm | #9

        Should have used structural paint. 

        "When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it."  T. Roosevelt

        1. User avater
          BruceT999 | Dec 22, 2006 08:41pm | #12

          Structural paint? Can you explain, please?
          BruceT

          1. User avater
            McDesign | Dec 22, 2006 09:16pm | #13

            <Structural paint? Can you explain, please?>

            It's got those little fibers in it, like in some concrete.  Also dissolved unobtainium.

            ;-)

            Forrest

          2. User avater
            JDRHI | Dec 22, 2006 09:46pm | #14

            He was joking about using it in this instance.

            Its typically used in the commercial building industry....block walls, cement floors, etc.

            Happy

            Holidays 

          3. FastEddie | Dec 24, 2006 06:05am | #15

            Wrpong.  Some "finish" carps I knopw use structura;l paint over structural; cau;lk to keep the door frames in place and fill the 1/2" gaps. 

            "When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it."  T. Roosevelt

          4. calvin | Dec 24, 2006 06:10am | #16

            Ed, good thing I had my decoder ring.A great place for Information, Comraderie, and a sucker punch.

            Remodeling Contractor just outside the Glass City.

            http://www.quittintime.com/

             

          5. FastEddie | Dec 24, 2006 06:12am | #17

            Keys are dpoub;le hitting.  Sopmetimes I gop back and c;lean uop, this time I ;let it gop.  man is this frustrating. 

            "When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it."  T. Roosevelt

          6. User avater
            AaronRosenthal | Dec 26, 2006 01:55am | #30

            Hey, Eddie, re your other post and the frustration you have.....
            Ever considered an accessory keyboard which can be plugged into one of the Dell's USB ports?Quality repairs for your home.

            AaronR ConstructionVancouver, Canada

             

          7. User avater
            JDRHI | Dec 24, 2006 08:35pm | #22

            REALLY?

            I think you're being incredibly generous, refering to them as finish carps.....even with the quotes.

            1/2" gaps aren't acceptable for framing....forget finish.

            Happy

            Holidays 

          8. Jer | Dec 24, 2006 06:34am | #20

            The ol' one two Bruce my boy. You can find structural paint in the same aisle as the left handed hammers and the skyhooks.

          9. User avater
            BruceT999 | Dec 24, 2006 09:14pm | #24

            "...same aisle as the left handed hammers and the skyhooks"Left-handed hammers, you say. Sounds like a sinister plot to me :)
            BruceT

  6. Jer | Dec 22, 2006 03:30pm | #11

    Is the crown FJ? Wood can move end to end even though 90% of wood movement is cross the grain. Winter is heating and dry season in a house, and typically new wood trim will tend to move. Is that a straight butt joint I see in the span? Should be a glued up angled scarf backed up with some sort of plate glued & nailed (or trim screwed), to the backside of both pieces. Some would say it's overkill but there's never the heartache that you have now.

    In any event, Allon is right. You should use a good flexible caulk in these cases and never putty for cracks like the ones shown here because it does nothing but move and re-crack. I use the Dynoflex, it's good stuff. Bondo is death for something like this. I would just caulk and repaint for now. Keep an eye on it though, it may want to move back.

  7. User avater
    Fonzie | Dec 24, 2006 06:23am | #18

    BrueT999,

    I'm going on a limb here and say that crown is plastic and you're seeing movement - that can't. The puzzle break doesn't look like wood to me - rather that starfoam stuff with a hard veneer. Have there been temp changes?

    1. FastEddie | Dec 24, 2006 06:25am | #19

      The geometric break is finger joint wood, cut flat rather than "quartersawn" 

      "When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it."  T. Roosevelt

  8. User avater
    dieselpig | Dec 24, 2006 08:51pm | #23

    I'd dig out all the other band-aids that have been tried there and start fresh.  Scrape/dig out the bondo and whatever else and then caulk with a good flexible paintable caulking.  Someone mentioned Big Stretch.  I'd carefully tool it to look as nice as a caulk filled mistake can look and re-paint.  Personally, I wouldn't offer any guarantees on it not resurfacing again sometime, but I think that's the best you can do given what you've got to work with.

    View Image
  9. User avater
    Pondfish | Dec 25, 2006 12:12am | #25

    Good demonstration why you should cope crown, even paint-grade.

    Recommending the use of "Hide Signatures" option under "My Preferences" since 2005
    1. DougU | Dec 25, 2006 02:10am | #26

      How can you tell if they coped or mitered!

      Doug

      1. User avater
        Pondfish | Dec 25, 2006 05:19pm | #27

        Post asked "whaddya use to caulk your miters", but also the bottom of the crown is a miter.  Could be a nice touch to a cope where one miters the last 1/4 inch, but the poster's comment said miter.  I'm guessing miter all the way through.

        Looking at the amount of dry shrinkage, even a cope would have opened up and revealed a lot.  But still, copes on a basic colonial crown aren't hard to do and will hide movement better.Recommending the use of "Hide Signatures" option under "My Preferences" since 2005

        1. DougU | Dec 25, 2006 08:12pm | #28

          Yea, all that that you said!

          I was just making a comment about the joint itself, I cant tell weather or not its a cope or miter, so full of fill of some sort.

          Doug

        2. User avater
          BruceT999 | Dec 25, 2006 09:02pm | #29

          Thanks for all your suggestions and conjectures, guys. I'll try the Dynoflex material. Should be real fun getting the bondo out of those corners. Young couple has limited budget. Maybe I'll wait for some really dry weather to shrink everything to the max, then try working Dynoflex into the existing cracks. CAGIV asked "what is causing the cracks? Movement or just drying out?"We live in earthquake country, but there hasn't been a temblor since they painted and no heavy rain to cause settling of the slab foundation, so I have to assume shrinkage. Since the HO's bought only 6 months ago, there's no telling how long the crown has been there or what type of material. We had unseasonably humid weather this summer, so the stuff probably did shrink sometime after the cracks were caulked. Pondfish said "I'm guessing miter all the way through."That's what I assumed when I looked at it, especially since the installer made an un-bevelled butt joint on one long run. A guy who doesnt bevel-cut butt joints wouldn't take the trouble to cope the corners either. You can't see it well in my poorly focused pics, but the bondo in the corners is distinctly rounded to at least 1/2" radius, as if the painter just ran his finger down it. That is almost certainly what caused the cracks in the corners to zig-zag.Thanks again guys
          BruceT

  10. spikeit | Dec 26, 2006 06:00am | #31

    looks like the installer had the same job as when he worked in the grocery store....butcher.......

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