Crown molding
Crown molding encapsulates a large family of moldings which are designed to gracefully flare out to a finished top edge. Crown molding is generally used for capping walls, pilaster
A pilaster is a slightly-projecting column built into or applied to the face of a wall. Most commonly flattened or rectangular in form, pilasters can also take a half-round form or the shape of any type of column, including tortile....

s, and cabinets
Cabinet (furniture)
A cabinet is usually a box-shaped piece of furniture with doors or drawers for storing miscellaneous items. Some cabinets stand alone while others are built into a wall or are attached to it like a medicine cabinet. Cabinets are typically made of wood or, now increasingly, of synthetic...

, and is used extensively in the creation of interior and exterior cornice
Cornice molding is generally any horizontal decorative molding that crowns any building or furniture element: the cornice over a door or window, for instance, or the cornice around the edge of a pedestal. A simple cornice may be formed just with a crown molding.The function of the projecting...

 assemblies and door and window hoods.

In recent times, crown moldings have generally made their appearance as mostly decorated plaster
Plaster is a building material used for coating walls and ceilings. Plaster starts as a dry powder similar to mortar or cement and like those materials it is mixed with water to form a paste which liberates heat and then hardens. Unlike mortar and cement, plaster remains quite soft after setting,...

 or wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

en trim where walls meet ceiling
A ceiling is an overhead interior surface that covers the upper limit of a room. It is generally not a structural element, but a finished surface concealing the underside of the floor or roof structure above....



Crown molding is typically applied along the seams where ceiling meets wall. Usually it is not placed flush against the wall nor against the ceiling. Instead, when viewed from the molding's end (or as a cross-section), it, the ceiling, and the wall form a "hollow" triangle. This adds a difficulty to the installation process, namely the need for complex cuts to form corners where two walls meet.

There are two common ways to fashion inside corners. One is to use a compound miter saw
Miter saw
A miter saw is a saw used to make accurate crosscuts and miters in a workpiece.-Manual miter saw:The basic miter saw is the manual miter saw. It is a saw suspended on rollers in a metal guide that works with a miter box that allows making accurate crosscuts and miter cuts...

 to cut the ends of the corner pieces along two axes simultaneously. The other, called coping
Coping (joinery)
Coping or scribing is the woodworking technique of shaping the end of a moulding or frame component to neatly fit the contours of an abutting member...

, is a two step process, first to cut a simple miter and then to use a coping saw
Coping saw
A coping saw is a type of hand saw used to cut intricate external shapes and interior cutouts in woodworking or carpentry. It is widely used to cut moldings to create coped rather than miter joints. It is occasionally used to create fretwork though it is not able to match a fretsaw in intricacy of...

 to undercut the miters.

Many different companies now manufacture crown molding in materials such as plastic and foam. These typically are offered with corner blocks, and are popular with DIY
Do it yourself
Do it yourself is a term used to describe building, modifying, or repairing of something without the aid of experts or professionals...

 home improvement
Home improvement
Home improvement, home renovation or remodeling is the process of renovating or making additions to one's home.-Types of home improvement:...


Using a coped joint for interior corners saves you the trouble of having to determine and cut the exact inside degree measurement since most corners are not exactly 90/45 degrees. Outside corners must be mitered, but use care because not all outside corners measure true. Measure and cut accordingly. If the angle is not exactly 45/22.5 degrees use a corner measuring device or piece of scrap crown molding to obtain the right measurement before you make your final cut.

Angle calculations

Fitting crown molding requires a cut at the correct combination of miter angle and bevel angle. The calculation of these angles is affected by two variables: (1) the spring angle (or crown angle, typically sold in 45 degree and 38 degree formats), and (2) the wall angle.

Pre-calculated crown molding tables or software can be used to facilitate the determination of the correct angles. Given the spring angle and the wall angle, the formulas used to calculate the miter angle and the bevel angle are:
  • Miter angle
  • Bevel
    A beveled edge refers to an edge of a structure that is not perpendicular to the faces of the piece. The words bevel and chamfer overlap in usage; in general usage they are often interchanged, while in technical usage they may sometimes be differentiated as shown in the image at right.-Cutting...


External links

Online Angle Generator and Crown Molding Installation Tutorials
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