8 Tips for Installing Wood Molding Like a Pro

Combine Moldings for Extra Drama

I love looking around old houses to see how wood moldings are combined to create baseboards, casings and cornices. I’ve even been surprised when removing old moldings to discover more layers than I originally noticed. The builders knew the advantages of combining small wood moldings. In addition to allowing endless possibilities for customization, smaller moldings are easier to cut and install than large moldings and allow more flexibility on wavy or irregular walls. Plus, combining small wood moldings can often achieve a great effect for less money. I made the decorative ceiling cornice shown above using moldings I found at a home center.

The best way to plan wood molding combinations is to get your hands on some short lengths of molding and play around with them. Many full-service lumberyards have wood molding samples available. At home centers, you may have to purchase short lengths of each molding you’re considering or ask for scraps.

Inspect Before You Buy

Wood moldings can vary quite a bit in looks and quality, so it pays to examine them closely when you’re picking them out. It’s not as critical if you’re installing trim that will be painted, but for stained moldings, there are several things to watch for. Make sure moldings that will be close to each other have a similar grain pattern and that the wood is about the same tone.

Chatter from shaper blades is another common problem to pay attention to. Although you can’t avoid chatter marks entirely, choosing wood moldings carefully can keep them to a minimum and significantly reduce your sanding time.

Also, watch out for “snipe,” gouge cuts near the end of the molding that is caused by the molding machine. That 10-ft. stick of molding you need may not give you a full 10 ft. of usable molding.

Put the Pinch on Miter Joints

I recently ordered four miter clamps and a special pliers-type tool to install them, and I am amazed at how well they work. These handy little clamps are basically bent spring steel with sharp points that grab the moldings and squeeze them together. They’re perfect for holding small pieces of mitered trim together while the glue dries and for clamping crown molding miters while you pin them together. They’re also great for picture frame assembly.

Spice Up Your Project With Reveals

Like every other rule, this one has many exceptions. But in general, when I combine wood moldings or add moldings to plain boards, I offset the parts so that the edges aren’t perfectly aligned. The exposed band of molding or board is called a “reveal.” Creating reveals has two big advantages. First, it allows a bit of flexibility since the two edges don’t have to be perfectly aligned. Second, reveals look better in most situations.

The typical method of creating a reveal is to set back the edge of the molding from the edge of the board, as shown here. However, an equally effective method is to allow the molding to protrude. Some reveals are set by tradition. Door and window casings, for example, are usually moved about 3/16 in. from the edge of the jamb. In other cases, you’ll have to trust your eye to determine the right amount.

Attach Small Parts With Super Glue

Mitered returns are tough to attach. They’re usually too small to nail unless you have a micro pinner. I’ve tried attaching small parts with wood glue, but often, the moisture from the glue causes the thinnest part of the trim to warp before the glue dries.

Use Nearly Invisible Nails

I was talking to John Frost, a local cabinetmaker, about how he installs wood moldings. After giving me many good tips, he said, “And of course you know about micro pinners.” Actually, I didn’t. John explained that a micro pinner is a finish nail gun that shoots super-thin 23-gauge pins.

He uses a micro pinner because the small-diameter pins leave smaller, almost invisible holes after filling them. Plus, the tiny pins allow him to nail very small parts without splitting them as thicker pins might.

Add an Auxiliary Fence

I asked a cabinetmaker friend if he ever added a fence to his miter saw, and he said, “Absolutely, always.” An auxiliary fence has several advantages. It reduces the gap under and behind the molding to only what the blade needs to fit through. The small gap helps prevent splintering on the back of the board and keeps small cutoffs from dropping through the fence and getting flung by the blade. You can also use the saw kerfs in the fence to help you line up your cut.

An auxiliary fence needs to be accurate but not fancy. I like to build fences from MDF because it’s straight, stable and inexpensive. Another good choice is 3/4-in. plywood. Make the back of the fence as tall as possible without letting it interfere with the motor housing or blade guard. If you need several short pieces cut to the same length, make the fence long enough to attach a stop.

Be sure the bottom and back are exactly perpendicular and that you don’t put fasteners where the blade will cut. If you own a plate joiner, use glue and biscuits to join the back and bottom—no need to worry about hitting fasteners. Attach the auxiliary fence with screws through your miter saw fence.

Create Original Designs With SketchUp

For this article, I worked on SketchUp, a drawing program from Google, to design a fireplace mantel and simple wainscot and window trim. I used moldings that I found at a home center and a local full-service lumberyard. The SketchUp model and some of the building details are shown here. I’ve been dabbling in SketchUp for a few years, but I still have plenty to learn.

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What I like best about this versatile 3-D drawing program is how quickly you can learn the basics and create useful drawings. You’ll be drawing 3-D shapes in minutes and be able to draw a simple bookcase with a few hours’ practice. I use SketchUp routinely to design sheds, build bookcases, or work out tricky building details.

TMB STUDIO