Tips for Trimwork
Removing and installing moldings -- a job builders call "finish carpentry" -- isn't especially difficult, but there are a few tricks to the trade. Here's how to get your interior trim project across the finish line.
Off with the old: How to remove trim
Pry off old moldings with care, lest you damage the wall behind the millwork (and the trim itself, if you plan to reuse it). If the trim has been painted, first cut along its edges with a utility knife to break the seal between the molding and the wall. The easiest way to save a base shoe without breaking it is to drive its finish nails all the way through with a nail set, as shown in Figure 1.
With wider elements, such as baseboards, crown moldings, and the like, first drive a pair of taping knives behind the molding, then work a pry bar between the knives and molding, as shown in Figure 2. The knives ensure that the pry bar won't gouge the walls. After you've loosened a few inches, wedge the molding away from the wall with a shim, then move along, prying and wedging as you go.
The best way to mark outside corners
Whenever possible, hold a piece of molding in place and mark it, as shown in Figure 3. This method provides greater accuracy than you'll get with a tape measure, and also lets you indicate the direction of the miter you need to cut.
Ensure a Tight Fit
How to ensure a tight fit
Install door and window casings and other vertical trim before you fit horizontal elements, such as baseboards and chair rails. Mark and cut these pieces about 1/16 inch longer than the space. If you're butting against a piece of casing, make sure it's well-secured so it won't move when you press against it. Install the horizontal pieces by bowing it into position, as shown in Figure 4. This will give you a tight fit at each end.