Im trying to achieve a very ornate crown molding, and Ive gotten the look I want by gluing 3 pieces of crown molding together and it looks perfect. Ive used glue on my sample test run which is only about 1 foot in length. But this will be for a room thats about 12 feet long so Im sure the glue method wont work in real world :)

My question is, whats the best way to actually attach these pieces together and is this just a stupid idea since the areas of attachment are generally so thin?

From my basic internet research it seems like using baseboards on either side and one crown molding looks much more stable, but I simple cannot achieve the look I want with that technique and having 3 crown moldings stacked is what I want to achieve

What does everyone think the best way to attach these pieces together would be?

Thank you!! enter image description here enter image description here

4 Answers 4


Yes, if you apply a plywood backer that's about 3/4 the width of the assembly. Crown mold takes a lot of stress and strain during installation, from fitment, mitering, coping, and nailing. Those thin joints are likely to crack apart during the process.

I'd back it up with either 3/8" BC plywood, or 1/4" birch underlayment (Tecply).

  • oh thank you! Do you mean like the image with nails that I just now added to my first post? Nails are marked in red
    – Mark
    Mar 7, 2016 at 19:11
  • I wouldn't use nails on the face. I'd use wood glue for the molding-to-molding joints and construction adhesive or urethane glue for the backer. I don't know what you had in mind initially, but you could also strategically use hot glue or contact adhesive in conjunction to eliminate the need for clamping.
    – isherwood
    Mar 7, 2016 at 19:18

I agree with Isherwood's Answer & Comment, glue to backer & to each other. But, just to twist in another option. I'd go with 1/2" plywood & use Finish or Trim Screws as your glue clamps so assemblies can go right up. Of course, install with Finish or Trim Screws as well in order to either conform to ceiling & wall (like nails will do) or to leave shy of tight & keep the crown straight.


If the pieces fit together the way you've pictured, an alternative might be to simply install them one-at-a-time. It would, of course, be more finnickey and you'd have to spend more time making sure they lined up the way you wanted, but you'd eliminate the extra thickness of the backing board. (If that's not important, then pre-assembly would likely be the better method as it's easier to line everything up neatly on a workbench than up near the ceiling.)


why dont you just get wider crown moldings? we have installed crowns almost 24" high. your time is worth money too

check these places:



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