Home Theater Crown Molding Notes 

This page contains notes on specific construction issues I ran into, including working with crown molding and panel molding. 

Crown Molding. Cutting crown molding is challenging, and I designed my theater to minimize beveled crown molding cuts. Nonetheless, there were a small number of 90 degree angles that I had to cut. DeWalt's website has some good notes on cutting crown molding. The common advice to try your cuts on scrap material is very important. The angles are very hard to get right, even using a reference table like the one on the DeWalt website. I personally concluded that trying to get the angles right by using an angle reference table and doing a compound angled cut was beyond my skill level. So I ripped a 45 degree block of wood to put against the fence on my saw, and then simply held the molding against the angled piece of wood and cut the angle I needed. This worked quite well. 

One problem I ran into was trying to align the outside corners of the two pieces of molding at the tops of the columns. I initially tried nailing each of the pieces of molding separately, but getting the ends to come together cleanly, at the right angle, and nailing each piece precisely enough so that the joint was snug seemed just about impossible. Part of my problem is that the columns aren't 100% square to the walls in the corner or to ceiling (and for that matter I don't think the walls are 100% square to each other or to the ceiling), and that compounded the problem of trying to get these pieces of molding turned and twisted so that the rested against (a) the column, (b) the ceiling, and (c) each other all at the same time. I ended up gluing the corners of the molding together on a workbench before I nailed the molding into place. Once the glue sets, the joint is so strong that you can bend the molding quite a bit without breaking the glued joint, and that made installing the molding at the tops of the columns a lot easier.  

Another issue I ran into was how to keep the long runs of molding in place securely and to make them strong enough to hold the wire runs that I was putting in them. I didn't want to pound a million nails into the molding. I started out by putting nailing blocks behind the molding. This is a standard technique where you cut a 45 degree piece of wood to put behind the molding; you nail that into the wall, and then you nail the molding into the nailing block. That gives you a better angle for the molding nail and helps keep you from splitting the molding. That worked OK, but it still wasn't as secure as I wanted. Since the molding was nailed well enough to stay up for awhile, I ended up just placing additional 45 degree blocks of wood between the molding and the wall with a little bit of glue on them. Once the glue dried, those blocks provided most of the support for the molding. If I'd discovered this technique earlier, I would have put even fewer nails into the molding--just enough to keep it up while the glued-blocks dried.