Install Decorative Moulding

Skill Level: Advanced

If you want to give your room a finished look and hide those slight imperfections where corners meet, consider installing decorative chair rail moulding. It is easier than many people believe, especially when you use corner blocks to eliminate miter cuts. The most important tool when working with moulding is patience. Never try to rush trim work. Remember the old adage, measure twice and cut once.

Tools & Materials

Tools Tape measure Dropcloth Drill/driver Dust mask Bits Caulk gun Hammer Paintbrush or staining brush Level Goggles Miter saw Nail set

Materials Wood putty Moulding Stain or paint Nails Caulk

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Installation Options

Decorative hardwood moulding can be installed a two ways. You can use the traditional installation method requiring miter, cope and scarf cuts or use the corner block installation method which allows you to install the moulding using only straight cuts.

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Locating, Cutting and Fitting

• General
• Start by cutting your moulding pieces a little long, you can always trim a little off, but once a piece is too short it can't be fixed.
• Predrill holes for nails to avoid splitting the moulding.
• If you use a power miter saw, use at least a 60 tooth blade.
• In order to establish a level line for a chair rail, measure up from the floor to where the bottom of the chair rail will be and make a mark. Use a level as a straight edge and lightly draw a line around the room. As you install the chair rail, make sure it is even with this line.

• Base and Chair Rail Corners
• Lay the moulding with its back flat against the bottom of the miter box or the bed of the power miter saw. For inside corners, cut through the face at 45° so the edge of the cut is visible from the front. For outside corners, cut through the face at 45° so the edge of the cut is hidden from the front. Cut the pieces as mirrors to each other.

• Crown Corners
  
  
  For outside corners, use a power miter saw and set it as indicated in in our crown moulding adjustment table. For inside corners, you can either miter cut the pieces or cope them.
• To miter the pieces, place the moulding so its top (the part that goes against the ceiling) is flat against the bottom of the miter box or bed of the power miter saw. The bottom (the part that goes against the wall) should be flat against the side of the miter box or the power miter saw's fence. Cut the pieces as mirrors to each other on 45° angles.



• To cope the pieces, butt one piece tight against the wall and nail in place. Place the second piece in your miter box or power miter saw as described above and cut the piece at 45° so the edge of the cut is visible from the front. Use a coping saw to cut a slight back angle following the contour of the exposed moulding profile. Test fit the coped cut and trim as necessary. See the animation below for more information on coping moulding.

• Splicing All Types of Moulding
  
  
  When you are covering a span that is longer than your moulding, splice two pieces together with a scarf joint. Lay the moulding with its back flat against the bottom of the miter box or the bed of the power miter saw. On one piece, cut through the face at 45° so the edge of the cut is visible from the front. On the second piece, cut through the face at 45° so the edge of the cut is hidden from the front. The joint should meet over a wall stud or some other point where it can be nailed.

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Determining How Much You Need

1. Measure the room at the height where each moulding will go to determine the number and the length of the pieces you'll need. Jot these measurements down.
2. Since decorative hardwood moulding usually comes in 8' lengths, divide your footage by eight and multiply that number by 1.1. The result is the total footage needed plus ten percent for waste. Perform this step for each type of moulding, base, chair rail and crown, separately.

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Applying the Finish

1. Apply the finish to the moulding before installing it. You'll save time because you can apply the finish faster. Find a dry, well-ventilated and dust-free area to apply the finish to your moulding.
2. Put down a dropcloth and apply the finish according to the manufacturers' instructions. Apply the finish to the moulding in the same order you intend to install the pieces. Then you won't have to spend as much time waiting for pieces to dry.
3. Set aside a small amount of the finish to touch up any raw edges.

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Installing the Moulding

1. Locate and lightly mark the wall studs (see How to Find Studs in Finished Walls).
2. Measure the distance between two inside corners and cut a piece of moulding to fit between the corners. Predrill the moulding at every wall stud and nail in place. To avoid denting the moulding, use a nail set to finish driving the nails home. You may need someone to help hold long pieces while you drill and nail. In the event you have a span between two corners longer than the moulding, simply make a scarf joint as mentioned above to splice two pieces.
3. Continue installing pieces until all the moulding is up.
4. After all the moulding is up, touch up any raw edges with a light coat of finish. Use wood putty or a filler stick to hide nail holes. For crown moulding, it may be necessary to apply a bead of caulk where the moulding meets the ceiling to close any gaps.

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Installing the Moulding With Corner Blocks

1. Determine how much moulding you need as above.
2. Count the number of inside corners in the room to determine the number of inside corner blocks you will need. Do the same for the outside corners. Plan on using divider (intermediate) blocks in any wall with a measurement greater than 8'.
3. Apply the finish as above.
4. Predrill holes for nails to avoid splitting the moulding or corner blocks. Predrill holes in the inside corner blocks and nail them to the inside corners of the room (see Predrilled Block). Try to drill the holes so the moulding will cover them. If the room has any outside corners, predrill holes in the outside corner blocks and nail them to the outside corners of the room.
5. Measure the distance between the first two corner blocks. Cut a piece of moulding approximately 1/4" longer than the measurement.
6. Butt one end of the moulding tight against one of the corner blocks. Lap the other end over the other corner block and trace the edge of the corner block onto the back of the moulding. Take the moulding down and cut it on the outside of the line to ensure a snug fit.
7. Locate and lightly mark the wall studs (see How to Find Studs in Finished Walls). Touch up the raw edges with a light coat of finish and fit it between the corner blocks. Predrill the moulding at every other wall stud and nail into place. To avoid denting the moulding, use a nail set to finish driving the nails home. You may need someone to help hold long pieces while you drill and nail. Continue this process until all the moulding is up. Use wood putty or a filler stick to cover any noticeable holes.
8. In the event you have a span between two corner blocks longer than the moulding, simply center an intermediate block between the two corner blocks. Install the moulding as you would between corner blocks.
9. In order to establish a level line for a chair rail, measure up from the floor to where the bottom of the chair rail will be and make a mark. Use a level as a straight edge and lightly draw a line around the room. As you install the chair rail, make sure it is even with this line.

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Building Up Moulding

1. Built-up moulding is usually associated with intricate crown mouldings on vaulted ceilings or the ornate mantels of colonial mansions. Although those patterns may overpower the average home today, you can use the same techniques to design your own personalized moulding. Gather several sample profiles. Experiment with them until you find a profile you like. (Learn more about building up moulding or check out our moulding profiles chart).
2. Once you decide on the profile for your built-up moulding, determine which piece should go up first. Select the most rigid piece or a piece that butts to a rigid surface like the floor or ceiling. Starting with the most rigid piece ensures straight lines and eliminates the flex that smaller mouldings can have. Next determine the order for installing the rest of the pieces.
3. Install the first piece as you would a single profile. Install each subsequent profile in its entirety before going on to the next.

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Compound Miter Saw Adjustment for Crown Moulding

Wall Intersection Angle Crown Moulding with 52° and 38° Edges Crown Moulding with 45° and 45° Edges Miter Adjustment Bevel Adjustment Miter Adjustment Bevel Adjustment 85° 33.90 35.52 37.66 31.42 86° 33.43 35.19 37.17 31.14 87° 32.97 34.86 36.69 30.86 88° 32.52 34.53 36.21 30.57 89° 32.07 34.20 35.74 30.29 90° 31.62 33.86 35.26 30.00 91° 31.17 33.53 34.79 29.71 92° 30.73 33.19 34.33 29.42 93° 30.30 32.85 33.86 29.13 94° 29.86 32.51 33.40 28.83 95° 29.43 32.17 32.94 28.54