What gauge nail gun for molding? Base and Crown


Everywhere I look online to figure out what gauge nail gun I need to install base and crown molding. I’m looking to install regular plain type molding in my house. The basic ones you get at Home Depot or Lowes, nothing too thick.

I currently have the Bostitch compressor and nail gun kit with the 16 and 18 ga. nail guns. I’m fine with buying a 15 ga. gun if I need to.


No need for the 15, you are fine with what ya have, use the right length.


For the base, the 18 is fine, use 2" nails. You’ll lose an inch in the molding and Sheetrock, just mark the stud locations, 1" into the studs will hold well.

For the crown it depends. If you put up a backer strip, you can get by with 2" nails, 18 ga will work fine. I shoot one up nearly vertical into the backer and a second horizontally just above. I found out the hard way it’s more than strong enough when I had to pull a piece out to reposition it. Without a backer, I would step up to 2.5" 16 ga nails.

The 18’s are preferred because they leave a smaller cleaner hole, but when you need more than 2" of nail, the thicker gauge gives you that.


Agreed. Since you already have 18ga and 16ga, use those first. If you want an excuse to buy another tool, 15ga will also work, but will take a little more time and effort to hide the nail holes.


+1 on the 16ga and 18ga for most of the trim that I think you are talking about.
15ga nailers come in handy when conditions may make trim move and pop more than usual with seasonal changes (especially with hot air heating) or when old walls are so irregular as to require the extra holding power. But if the walls are really that wavy - why not fix that issue first? When using trim that’s going to be stained - its always good to try to use the smallest gauge nail possible. When painting trim you will probably be filling, and sanding anyway - but its still an issue for the painters.


While not ideal, I have been installing base, crown and casing in my house with just 18 ga naillers, as that is all that I have. Well 18 ga, plus liquid nails in certain places. The holes cover easy, and the nails, when placed well hold well enough. In addition to the liquid nails, I caulk everything in place before painting, so nothing is coming down until I want it to.


Thanks everyone for the advice. I’ll just keep what I have, I’d rather spend the money on something else tool-related. I do hate filling and touching up the paint. Whatever I used for the last time I did baseboard didn’t work all that well.

Backing strips recommended for the crown molding? Might just have to get a table saw for that…

Once I finish up a couple other projects I’ll start on the baseboard and then once that’s done work on the crown molding.

Hard to find the time to do it, I think my kid is still scared of the nail gun and it wakes her up when she’s sleeping.


Some links regarding backing strips:

Not always needed IMO on ceilings if you can nail into studs, joists or other structure - and you typically can with small crown (say less than 3 inches) using a 2-1/2 inch long 15ga or 16ga finish nail. Doing some nail angled criss-crossing also gives better support.
We had clients who wanted big or built-up crown moldings - (some of them- even though they had only 8 foot ceilings) - so in those cases backers were needed. Backers are also important for crowns installed where only 1 edge is supported (like on cabinets and built ins.)


The 16 and 18ga compressor you are using is fine for the work your doing. For Crown Molding these tools are perfect.