My design drawing has a simple trim around window but my contractor did not ask me and applied stucco around the window. Now I can only add the trim on top of stucco. I want to make sure the trim is weather resistant and its application should not subject the stucco wall to leakage.

I would like to know what is the best material for window trim on stucco? Is HardiTrim (HZ10, 1" x 3.5") too heavy to be placed on stucco?


You can use wood molding on top of stucco. I had the exact same situation as you describe and I did the following:

  • use a mortar scraper or similar tool to smooth rough stucco in the area where molding is to be installed

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  • drill mounting holes in molding and countersink
  • mark stucco at mounting hole locations and drill and install plastic plug anchors, filling anchor holes with weatherproof caulk prior to tapping in anchors.
  • install molding with screws that sit flush (countersink), fill plastic anchors and molding holes with weatherproof caulk first.
  • cover countersunk screw heads with exterior spackle and sand smooth.
  • use paintable caulk all around molding perimeter.
  • prime and paint

I'd use a moulding rather than a trim and glue it on.

  • I always thought trim and moulding are the same thing. What makes them better than the generic wood trims? I just need a 3.5" wide smooth trim around my windows. Can I glue wood or fiber cement trims on stucco instead? My main concern is waterproofing and durability. – some user Mar 24 '17 at 18:54
  • To me, trim is wood and moulding is foam. Foam can be shaped, cut, fit like trim, but it's inert so it won't rot if you don't get it sealed to the house exactly right. That way you can leave your existing exterior finish "as is" and just add moulding. – Lee Sam Mar 24 '17 at 19:59
  • I researched on the foam trim and watched a youtube video of how it is installed. It seems much more complicated than I anticipated. Basically, it is not just clued on but also stucco is to be applied on surface all around. Which means it will not have the simple look that I am after. I am less concerned about wood trim rotting as it can be replaced but rather I am concerned if nailed on, rain will penetrate through the gaps and causing water damage. – some user Mar 25 '17 at 4:52
  • I agree, nailing trim on is not "best", because of the possibility of leaks at nails, and yes, foam is a lot of work. – Lee Sam Mar 25 '17 at 6:35

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