I want to install a wood single piece crown molding. Given that my ceiling trusses only run one direction, I will have nothing to nail into on two of the 4 ceiling sides of my room. I dont want to glue a backer board to my ceiling. Dont want to glue anything to my walls in case I need to take crown molding down. Is it necessary for me to nail the crown molding to the ceiling as long as I am nailing the crown molding into the studs in the walls? thx

  • Why would you need to glue the backer board? Just nail it to whatever blocking is carrying the corner of the ceiling.
    – Comintern
    Sep 20, 2015 at 3:29
  • Can you provide the dimension of the crown molding? Unless this molding is of the very huge variety you should be able to make a nailer strip that has a 45 degree right triangle cross section. This strip can be nailed or screwed to the top end of the studs along the wall. For larger profile molding you could consider cutting individual triangles out of 3/4" board that you attach to the wall at each stud location.
    – Michael Karas
    Sep 20, 2015 at 11:32
  • If you're desperate to avoid nailers (and your crown isn't bigger than 4"), shoot lots of nails at 90 degrees to each other. (In other words, shoot a nail at 45 degrees, then put another one nearby at the other 45 degrees.) Wherever you see a sag, shoot a pair like this. Caulk generously and call it a day. If you're a perfectionist, take some of the other advice here. (Oh, and if you do go with angled nailing strips, best figure out if you have 45 or 38 or other degree crown.) Sep 20, 2015 at 20:55
  • Great info. Thx for all the advice guys.
    – sdbqwert
    Sep 23, 2015 at 16:00

1 Answer 1


Yes you definitely need to nail your crown molding into the ceiling joists as well it will prevent the top edge that is attached to the ceiling from sagging over time. I've done trim carpentry for ever 20 years.

  • OK. If the ceiling joists are parallel with the wall I am installing the crown molding on then there may not be a ceiling joist for me to nail into. If this is the case, what option do I have other then gluing a beveled 1X4 strip onto the ceiling that I can nail into. I really dont want to glue anything to my sheet rock.
    – sdbqwert
    Sep 20, 2015 at 3:31
  • Nail as high as you can on the crown moulding into the top two by four of the wall would be my best answer if you do not want to use a wood nailer strip behind the crown molding Even if you do have problems it wont be for a while and it would only be a slight separation from the ceiling to the top of your crown which can probably be cured with caulking anyway. It's just that the ideal circumstance of course is to nail it into the ceiling joists as well so you won't have any of those issues but if that's not available I understand your circumstances being unique that you are opposed to a nailer
    – user41750
    Sep 20, 2015 at 3:49

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