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How to Install Crown Molding

Of all the interior trim options available, crown molding makes the greatest impact in an otherwise plain room. Gracefully bridging the transition between walls and ceiling, it provides an eye-pleasing line that delineates the space.

To mark for crown molding, use a 3- to 4-foot length of the molding itself as a guide rather than a ruler or tape measure. Holding the molding in place, mark the ceiling first and then the wall line.[GARD align=”right”]

Cutting crown molding can be a bit confusing. As you move from ceiling to saw, it’s easy to lose track of what cut goes where. Here’s an easy way to stay oriented:

Think of the ceiling as a picture in a frame, with the crown molding acting as the frame. When you’re cutting, the surface of the saw table becomes the “picture” and the saw fence the “wall.”

Note the position of crown molding when cutting.

This means that you will make all cuts with the moldings upside down, as shown above. Remember this and you won’t be confused about how to place the stock on the saw.

You should cope joints wherever possible, so inside-corner junctions will have a square cut on one piece and an inside miter on its mate.

Outside corners, if you have any, require outside miters on both mating pieces. Fine-tune the fit with a block plane, rasp, and sandpaper.

Install crown molding with nails and glue, predrilling and driving the nails into the wall framing wherever possible. With large, heavy crowns, you may want to use backing blocks.Cut triangular blocks from 2-by stock of sufficient width to fill in the angled back of the crown. Screw the blocks to the wall framing with 3-inch wallboard screws. Nail the crown molding to the blocks.[GARD align=”left”]

When you fasten crown molding, nail it to the ceiling first and then to the wall. This ensures a true line at the ceiling, where the eye most needs to see it. Any gaps that may appear in the wall line due to irregularities in the wall surface are usually easy to handle.

If the ceiling is uneven, test-fit with the molding resting on the bumps, shimming and caulking in the hollows. This will usually look fine. In extreme cases, you may want to run the molding 1/4 inch below the ceiling and leave it uncaulked.

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How to Join Interior Trim

When two pieces of trim meet at an angle-most commonly a 45-degree angle to form a 90-degree corner-this is called a mitered joint. In the case of a typical window casement, miters are cut across the face of the molding; for a return or scarf joint, the cut is across the thickness. Crown molding requires compound miters, which are cuts across both.

The best joint for inside corners is a 45-degree miter. Accurate  measurements are a key to success.

[/media-credit] The best joint for inside corners is a 45-degree miter. Here, the piece on the right still needs to be cut. Accurate measurements are a key to success.

Outside corners of crown molding, chair and picture rails, and baseboards require outside miters. Inside corners require coped joints. The corners of window and door casings require flat miters that are exactly like the corner joints in most picture frames.[GARD align=”left”]

For the mating pieces to fit together seamlessly, each must be cut at precisely the same angle-preferably 90 degrees. In cases where the angle may not exactly total 90 degrees, you can trim up the pieces after cutting according to the angle guides on your miter saw.

To cut any other size angles, divide the total angle of the corner in half, adjust your miter saw’s guide, cut, and then fit the pieces together. Trim or back cut as needed to produce a tight joint.

After drilling pilot holes, nail in the pieces, and then place one “clinching” nail through an edge to help secure the joint. Keep nails about 3/4 inch from the end of a joint to prevent splitting the wood.

This crown molding is coped to fit its mate.

Where two pieces of trim meet at an inside corner, you may be tempted to cut each at a 45-degree bevel and butt them together. Unfortunately, this method often results in unsightly gaps. Instead, pros use a coped joint, which seems difficult at first but is actually fairly quick and easy to do once you get the hang of it. Use coped joints for baseboard, chair rail, crown molding, and anywhere else two pieces of trim meet at an inside corner.

Emphasize the curved cut you’ll make with a pencil.

To start, cut the first piece of trim at a 90-degree angle, butt it tightly into a corner, and nail it into place. For the next piece, which will be cope cut, use a board that is longer than needed; you will cut it to length after making the coped joint.

The next steps don’t seem as if they will work, but they will. Use a power miter saw or a hand miter box to cut the second piece at a 45-degree bevel, with the back of the trim longer than the face.

Cut the curve with a coping saw.

The face of the trim end now has a profile that will follow the contours of the trim piece already installed; you just have to cut away the back portion. To emphasize the line of the curved cut you will make, run the side of a pencil along the edge.

Use a coping saw, which has a very thin blade that allows you to cut tight curves, to cut along the line. Hold the saw blade at slightly more than a 90-degree angle to the face of the trim so you cut off a bit more of the backside than you need to.

Test the fit; it should be tight all along the profile. If not, you may need to cut away some of the back of the trim using a utility knife.

Hold the cope-cut piece in place and mark it for cutting to length at the other end. Then nail it into place.

How to Create Butt Joints with Trim

Wall Trim Butt Joint

The easiest of all trim joints to create is the butt joint. The end of one piece of trim is simply placed flat against the side of the the other, and then the edges are affixed to the wall with painter’s caulk.

A butt joint is used where two pieces of trim with a square profile come together, such as at an inside corner; where a side casing meets a window stool, plinth blocks, or the floor; or where a thinner piece of molding meets a thicker piece.[GARD align=”left”]
Do not use a butt joint for an outside corner because the exposed end of the one piece cannot be finished in any way that will make it attractive. Though a butt joint is simple to make, the best join with no gapping whatsover. In fact, there should be no visible line without close inspection. While caulk can close up a small gap, it is better to cut the joint to fit tightly as the caulk will fail over time.Fit the pieces together, and then make the necessary adjustments in the mating piece. Continue test fitting until the pieces fit snugly.

How to Repair Gaps Along Moldings

Run a bead of caulk along gaps between moldings before painting.

Molding and trim generally look best when they are fitted tightly to walls and ceilings. Small gaps show shadow lines and leave the trim looking unfinished.

To fill gaps between moldings and the ceiling or walls, apply a bead of siliconized-latex caulk. This is flexible enough to ride out any movement caused by moisture changes.

Apply a 1/8-inch bead of the siliconized-latex caulk with a caulking gun, and then dampen your finger with water and smooth the caulk.

How to Repair Molding Corners

Moldings look great when they are tightly fitted together, but when gaps open up between them, particularly at corners, they can look somewhat shabby. Fortunately, fixing this situation is very easy.

If mitered corners of base moldings are separating, squeeze a little wood glue in the joint and re-nail with finishing nails. Set the heads and fill with wood putty to match. If the nails don’t hold, ask your hardware dealer for trim screws-very narrow screws with a tiny head that can be driven with a drive bit in an electric screwdriver or drill.

If trim around windows and doors begins to separate at the corners, you can squeeze some wood glue at the joint and then pre-drill a pilot hole and drive a 6d finishing nail through the side of one molding piece into the end of the other. Gently set the nailhead beneath the surface (don’t split the wood), and then fill with wood putty or filler and touch up with paint.


Attaching Interior Trim Securely

How to Install Crown Molding

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Attaching Interior Trim Securely

Because trim boards are often thin and narrow, they must be anchored firmly or they could pull away from the wall or joints between trim pieces could develop noticeable gaps.

Finding Wall Studs

In most cases, trim should attach to wall studs, which are usually (but not always) spaced every 16 inches on center, meaning the center of one stud is 16 inches away from the center of the next stud. In newer homes, studs are pretty consistently 16 inches on center, but at the ends of a wall at least one stud will be a shorter distance away from the end. In an older home, stud spacing may be surprisingly inconsistent, so you need to find each stud individually.

A stud is 1 1/2 inches thick. To ensure a good connection, don’t just find the stud, find the center of the stud. Otherwise, you may drive a nail into the stud’s edge, which will make for a weak attachment.

If the wall is drywall, a stud sensor (or stud finder) will reliably indicate stud positions. Or, try rapping along the wall; when you hear a less hollow sound, you are probably rapping at a stud location. Drive a test nail or screw-in a spot that will be covered by the trim piece-to make sure you’ve found the stud.

On an old lath-and-plaster wall a stud finder will be less reliable because there is wood lath nearly everywhere. Test-drive screws or nails to find the studs.

Trim nails should penetrate into wall studs. Photo: Copyright Sunset Publishing Corporation

Hand Nailing

Use trim nails that will penetrate at least 1/2 inch into the studs. To choose the right-sized nail, add to that 1/2 inch the thickness of the drywall, usually 1/2inch, and the thickness of the trim board.

Standard finish nails usually work fine. However, many carpenters prefer to use galvanized finish nails. They hold a bit firmer because they have a slightly rough surface, and they resist rusting, which is occasionally a problem. If you want a very small hole, consider using “hard trim” nails, which are very thin.

Set finishing nail heads below the surface, using a nailset. Photo: Copyright Sunset Publishing Corporation

If you are driving a nail within 2 inches of the end of a board, drill a pilot hole first to ensure against splitting the board. Drill through the molding piece but not deeply into the stud or the nail may not hold tightly. The hole should be slightly narrower than the shank of the nail. In the middle of a board, pilot holes are usually not necessary.

If you miss the nail and hit the board instead, you will produce an unattractive “frown” or “smile” in the board. Practice nailing on scrap pieces until you feel proficient.

Pound the nail until its head is slightly above the surface of the board. Then hold the tip of a nail set against the nail head and tap with a hammer to drive the head about 1/8 inch below the surface of the wood. Once you have driven and set all the nails, go back and fill the holes with wood filler. Allow the filler to dry and then sand lightly.

Using a Power Nailer

Pneumatic nailer makes nailing trim a breeze.

Fastening with a power nailer has great advantages over hand nailing. It goes much quicker, there is less chance of marring the wood (as often happens when you miss the nail with a hammer), you can hold the piece with one hand while you drive the nail with the other hand, and there is less chance of dislodging surrounding pieces with repeated blows of a hammer.

Power nailers are now fairly reasonably priced. A handyperson is usually best off buying a kit that includes two or three nailers and the compressor. For trim, you can use a nailer and/or a stapler. Short staples attach more firmly than short nails. Trim nails for power nailers are quite thin, so you may need to use more of them than you would if you were hand nailing.

The compressor will likely weigh about 45 pounds, but it will not be difficult to carry. You will need to plug in the compressor, attach the hoses, and wait for a minute or two while the compressor (noisily) builds up air pressure.

You can also buy nailers that do not use compressors but instead are powered by cartridges. These are typically more expensive, but you won’t have to schlep a compressor and hose around.

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Accurately Measuring Trim During Installation

Expert advice on how to accurately measure interior trim during installation, from choosing and using the right measuring tools to using a story pole.

When measuring trim boards for cutting, even the pros make occasional mistakes of the “d’oh!” variety. So take the time to measure carefully and recheck your measurement to be sure you will not waste a good piece of molding. Following are some measuring tips. (For installing crown molding, which calls for specific techniques, see How to Install Crown Molding.) how to measure trim

Checking Your Trim Tools

First, test to make sure your measuring tools are accurate. If you are working with a helper, take a measurement with one tool while your helper measures with another and compare your results.

A tape measure’s hook slides back and forth about 1/8 inch-the exact thickness of the hook-so that you get the same measurement whether hooking it or butting it. Test it on a scrap piece to make sure the measurement is the same both ways.

A level often goes out of alignment. Place your level on a flat horizontal surface, note the position of the bubble, and then flip the level over. If the bubble is not in precisely the same position, it may be time for a new level. Otherwise, you will need to flip the level every time you measure and make a line or hold the board in a midway position. Perform the same test while holding the level against a vertical surface to make sure you are getting accurate plumb lines.[GARD align=”left”]

Framing squares rarely go out of square, but they do get bent, which can throw off your measurements. Test yours against two factory edges of a piece of plywood. A solid angle square (also called a speed square) is almost always reliable.

Keep in mind that a power miter saw or circular saw will typically cut a line (or kerf) about 1/8 inch wide. A hand backsaw will probably have a narrower kerf.

Good Trim Installation Habits

Work methodically to ensure that you measure and mark each board in the same way. When using a tape measure, call out to your helper (or softly to yourself) the measurements.

If you use a carpenter’s pencil, take the time to sharpen it cleanly so you can draw thin lines. Many trim carpenters prefer to use a standard pencil; others mark with a knife instead of a pencil.

Draw a V rather than a single line, with the point of the V indicating the precise location for the cut. Then use a square to draw a line through the V, and mark the waste side with an X to make sure you cut the correct side of the line (you want to cut so the line remains on the trim piece).

Dealing with Sixteenths

Counting up sixteenths of an inch is tedious and often results in mistakes, so, for instance, if the measurement is 14 3/16 inches, some carpenters say “14 and a quarter minus,” meaning 1/16 short of 14 1/4. Others say “14 and a quarter short.” Still others say “14 and a quarter; cut the line,” meaning you should cut off the entire width of the line (which tends to be about 1/8 inch wide). To indicate 14 5/16, use “14 and a quarter plus,” or “strong,” or “leave the line.”[GARD align=”left”]

Copyright Sunset Publishing Corporation

A story pole simplifies marking multiple pieces that are the same size. Photo: Copyright Sunset Publishing Corporation

When marking for a cut, use the simplest method with the fewest possibilities for error. Often the best option is to hold a piece in place against the wall and mark it rather than use a tape measure. This method often works when one end of the piece ends at an outside corner, but this will not work when you are measuring from inside corner to inside corner.

Before holding the piece in place, check to make sure the end you will not be cutting is square as you cannot always trust boards to come square-cut from the factory.

When measuring for a door casing, scribe a line along the edge of the jamb indicating the amount of the jamb edge you want to reveal-typically, 1/4 or 3/8 inch. Hold the vertical casing pieces in place and use the scribed line to mark them. Once the two verticals are in place, hold the horizontal in place against the verticals to mark it.

Using a Story Pole

When installing a chair rail or other molding around the middle of a room’s walls, you want all the pieces at exactly the same height. You can do this by drawing level lines, but that’s time consuming. As long as your floors are reasonably level, using a story pole is easier.

You can make a story pole out of a piece of lumber or trim. Mark it with the height of the moldings you want to install. Hold the pole in position and mark the wall at various points or mark either end of a wall and snap a chalk line between the marks.

Measuring tape’s end hook eases measuring. Photo: Copyright Sunset Publishing Corporation

Hooking a Measuring Tape

If a piece is cut at an angle on the end you are not cutting, it will be difficult to hook the tape measure to it. Instead, lay the trim piece along a 1-by board, with its end even with the end of the 1-by, and hook the tape to the 1-by instead.

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How to Strip Paint from Trim

After multiple paint jobs in a home, interior trim can become caked with many layers of paint. When this happens, it can begin to lose the interesting contours, shapes, and details. If this is the case with the trim in your home—or if you want to remove the paint entirely so you can apply a natural wood finish—you may be faced with stripping the earlier finishes from the surface.

Wear rubber gloves when using paint stripper for removing paint.

Wear rubber gloves when using paint stripper for removing paint.

But be warned—this can be a very tedious job. Unless the trim is particularly unique, you may be better off removing it and replacing it with new, matching trim. Stripping paint is not only difficult, but often fails to give you the results that you’re hoping for.

It’s also important to recognize that paint applied before 1978 may contain lead. Before stripping it, it’s important to test for the presence of lead. Sanding or scraping paint that contains lead can be very hazardous to the health of your family. You can buy in inexpensive lead-test kit at home improvement centers.

Chemical strippers generally work best at removing paint from fine woodwork or irregular surfaces. Wear rubber or neoprene gloves to protect your hands, and protective goggles. Be sure to pay attention to the label directions on the stripper, especially regarding the need for proper ventilation. For some chemicals, you will need to wear an organic vapor respirator with new cartridges. Water-based strippers are the least noxious.

Before applying a stripper to your trim, be sure it’s made of wood, not plaster. Strippers can damage plaster trim.

Apply the stripper in one or more thick coats and let it work according to label directions. Don’t scrape too soon. After it has worked its way down into the paint, layers of paint should be easy to lift with a scraper. On vertical surfaces, choose a stripper that has plenty of body so that it doesn’t drip and run.

Be sure to protect the floor with plastic sheeting that has been taped with masking tape around the perimeter. Put newspapers on top to absorb the sludge. Also use painters tape and plastic sheeting to protect the walls from the stripper.

How to Remove Interior Trim

Expert, step-by-step illustrated guide shows you how to remove interior trim without damaging the trim or the wall. 

If moldings and trim are badly damaged, it’s best to replace them. This work isn’t particularly difficult, but it does take a little experience at making accurate cuts using a miter box. If this isn’t something you have done before, you’re probably better off calling a finish carpenter or cabinetmaker to do the work.[GARD align=”left”]

remove interior trim prybar

First insert a prybar behind the trim and pry the against a small wood block.

If you are removing molding and trim as part of a remodel with the intention of reusing them, you may be able to save a few dollars by doing the work yourself.

If paint is binding the molding to the wall, use a utility knife to score the paint along the edges of the molding. Then use a stiff putty knife to separate the molding slightly from the wall and create a space for a pry bar. Slide the putty knife back and forth until you hit the finishing nails that hold the molding to the wall and then follow these steps.

How to Remove Baseboard

1Insert a pry bar at one set of nails and place a scrap of wood behind the bar to protect the wall. Pry gently outward to bow the molding away from the wall and loosen the nails. Move to the next set of nails and repeat the process until you’ve loosened the molding along its entire length.



If a nail won’t pry out, use a nailset to drive it deep into the trim, then pry away the trim.


2Sometimes the nails won’t loosen, and prying will cause the nails to pull through the molding. If the nails are stuck, use a nailset to drive them about three quarters of the way through the molding’s thickness. You need not go all the way through.



You can ease molding away from the wall by prying in two locations.



3Work with a pair of pry bars to remove the molding, leapfrogging the bars in turn to gradually ease the molding away from the wall without cracking or breaking it. With the molding off, use a hammer or pry bar to remove any nails that remain in the wall. Label each piece as you remove it so you know where to replace it later.


Removing Door and Window Trim

Door and window trim is often nailed with a small nail at the mitered corners. If you pry at these points, the wood may split. First, use a mini-hacksaw to cut off the nails at the joint. If you do end up splitting trim when removing it, just glue it together and then put a rubber band around it or tape it with masking tape until the glue dries. copyright-sun


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