How to Transform a Room with Crown Molding

Create a new look in a room by installing crown molding to bridge the gap between walls and ceiling. It's easier than you think!

Atlanta Show House
Project Overview
  • Working Time: 3 hours
  • Total Time: 1 day
  • Skill Level: Intermediate

You don't have to move walls to create a new look for a room. Thankfully, you can dramatically alter your decor by working with much more manageable details: moldings and trim. Along with paint color and window treatments, moldings are a simple way to add style and definition to any room. Crown molding in particular bridges the junction between walls and ceiling, a prominent location where the architectural accent can shine. Our directions show you how to install crown molding in just a few easy steps.

Before You Begin: Choose the Right Molding

Home centers offer a variety of premilled molding materials. For the traditionalist, or if you plan to stain the trim, solid-wood trim available in many species is the best choice, albeit a more expensive one. If paint will cover your molding, consider finger-jointed wood, wood composite, or urethane trims to lower costs.

Urethane molding trim offers additional flexibility: it is lighter weight, can be installed with just construction adhesive, and generally allows you to use heftier profiles.

Custom milling can be done by local woodworking shops, but going this route will add quite a bit to your costs, especially if the shop has to custom-design a cutting blade for the profile you want.

Think ornate and layered for more formal or traditional looks; contemporary styles are best achieved with fewer, simpler profiles.

What You'll Need

Equipment / Tools

  • Measuring tape
  • Stud finder
  • Pencil
  • Electric miter saw or a miter box and handheld saw
  • Coping saw with spare blades
  • Pneumatic finish nailer with air compressor, available at rental stores if you don't own one
  • Drill


  • Molding to go around the room
  • Paint or stain for molding
  • Painters tape
  • Fine-grit sandpaper
  • Caulk
  • Nail set
  • Finishing nails
  • Patching compound or wood filler


  1. Take Measurements

    Measure the width of each wall along the ceiling. Moldings are often sold in standard lengths, so purchase the size that requires the fewest joints for your room.

  2. Prefinish the Molding

    Paint, seal, or stain and varnish the molding before installing. Let dry. Don't worry if it's not perfect; you'll touch up the paint/seal/stain later.

  3. Locate Wall Studs

    Moldings should be nailed into studs or ceiling joists rather than directly into the drywall, so scan the walls and ceiling with a stud finder, and make light pencil marks (or mark with blue painters tape) to indicate the studs and joists. Mark a few inches away from the wall-ceiling joint so you can still see your marks after you put the molding in place.

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    Decide Where to Start

    Work from one point around the perimeter of a room. That way you'll have only one closer piece that must fit precisely against adjacent moldings on each end. Generally, it's a good idea to begin in an inconspicuous corner, such as over the entry door to the room.

    Editor's Tip: Never assume that two surfaces meet at a true 90-degree angle; adjust cut angles to eliminate gaps.

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    Find the Right Type of Corner Joint

    When two molding pieces meet at an outside corner, use miter cuts (cutting the pieces at 45-degree angles) at the meeting end of each. When moldings meet at an inside corner, irregular wall surfaces usually create a poor fit if you use mitered ends. Instead, cut one molding with a square end and the other with an inside 45-degree miter.

    Then use a coping saw to cut along the contoured edge of the mitered molding, removing the exposed end-grain stock. File and sand the cut until the contour fits snugly against the adjacent molding. Use extra blocks of molding to practice first, and make repeated test fits and trim cuts until you get it right. Touch up with caulk and paint or stain after you finish.

    Editor's Tip: Use corner pieces, plinth blocks, and other transition pieces where possible. They make for simpler installation than miter cuts, and joints tend to stay closed despite seasonal changes in humidity.

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    Attach the Molding

    Nail each piece in place, but don't countersink the nails yet. If you are power-nailing with a pneumatic nailing gun, drive in only enough nails to hold the molding securely. That way you can remove molding with little or no damage to the pieces if needed. If you're using a large crown molding, install a hidden nailer strip behind it to provide more surface area to nail into.

  7. Splice Long Pieces

    When a long wall forces you to create a joint between two pieces of molding, cut a scarf joint (overlapping 45-degree beveled ends) for a less conspicuous joint. The exception for this is large crown molding. Making angled cuts in this stock is difficult, so pieces will likely fit better with square cuts butted against each other, creating a butt joint. If possible, always start by precision-cutting one end of the molding and leaving the other end about ¼ inch too long, then position it in place to mark the precise length to cut.

    Editor's Tip: Invest in the proper tools to get good results. Molding requires precise cuts regardless of the style or type. Painted moldings generally make it easier to camouflage imperfect fits. Make practice cuts on some short sacrificial stock before you cut the longer pieces.

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    Tidy Up the Details

    After all molding pieces are fitted properly, finish driving and countersinking the nails. For nails near ends, drill pilot holes to prevent splitting the wood. Fill nail holes with wood filler or patching compound, then sand. Use caulk or wood filler for small gaps at corners. Touch up nail holes and corners with paint or stain.

    Editor's Tip: Keep a consistent scale from floor to ceiling. Although it's tempting to install an impressive wide crown molding and skimp on the base or casings, molding sizes should be balanced throughout the room.

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