Crown molding (interchangeably spelled crown moulding in

British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories and Crown Dependencies. * British national identity, the characteristics of British people and culture ...

and

Commonwealth A commonwealth is a traditional English term for a political community founded for the common good. The noun "commonwealth", meaning "public welfare, general good or advantage", dates from the 15th century. Originally a phrase (the common-wealth ...

English) is a form of

cornice In architecture, a cornice (from the Italian ''cornice'' meaning "ledge") is generally any horizontal decorative Moulding (decorative), moulding that crowns a building or furniture element—for example, the cornice over a door or window, ar ...

created out of decorative moulding installed atop an interior wall. It is also used atop doors, windows,

pilaster In architecture, a pilaster is both a load-bearing section of thickened wall or column integrated into a wall, and a purely decorative element in classical architecture which gives the appearance of a supporting column and articulates an ext ...

s and cabinets. Historically made of

plaster Plaster is a building material used for the protective or decorative coating of walls and ceilings and for moulding and casting decorative elements. In English, "plaster" usually means a material used for the interiors of buildings, while "re ...

or wood, modern crown moulding installation may be of a single element, or a build-up of multiple components into a more elaborate whole.

Application

Crown moulding is typically installed at the intersection of walls and ceiling, but may also be used above doors, windows, or cabinets. Crown treatments made out of wood may be a single piece of trim, or a build-up of multiple components to create a more elaborate look. The main element, or the only in a plain installation, is a piece of trim that is sculpted on one side and flat on the other, with standard angles forming 90-degrees milled on both its top and bottom edges. When placed against a wall and ceiling a triangular void is created behind it. Cutting inside and outside corners requires complex cuts at standard angles, typically done with powered compound miter saws that feature detents at these angles to aid the user. An alternative method,

coping Coping refers to conscious or unconscious strategies used to reduce and manage unpleasant emotions. Coping strategies can be cognitions or behaviors and can be individual or social. To cope is to deal with struggles and difficulties in life. It ...

, is a two step process that begins with cutting a simple miter on both mating trim ends, then uses a coping saw to back-cut at least one of the miters along its profiled edge to provide relief during installation. Simplified crown installation is possible when using manufactured corner blocks, requiring only simple butt cuts on each end of lengths of trim. Plastic and foam versions of crown are now available, typically with corner blocks, for easy installation by DIY

home improvement The concept of home improvement, home renovation or remodeling is the process of renovating, making improvements or making additions to one's home. Home improvement can consist of projects that upgrade an existing home interior (such as electr ...

enthusiasts.

Angle calculations

Fitting crown moulding 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° and 38° formats), and (2) the wall angle. Pre-calculated crown moulding 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

= \arctan\left(\frac\right)

Bevel A bevelled edge (UK) or beveled edge (US) is 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 ...

angle

= \arcsin\left(\cos \times \cos\right)

Gallery

File:Back-cut_crown_molding_return.jpg, The relief on this short 90-degree return of crown molding was back-cut with a coping saw File:Wilkenson 154.jpg, A compound crown molding built up out of several individual trim elements File:Pilaster_topped_with_crown_molding.jpg, Decorative pilaster of natural cherry hardwood topped with crown molding File:Crown_molding_at_Bray_House,_Kittery_Point,_Maine.jpg, Crown molding may be a complex build-up of multiple trim elements, in this case built-out slightly above a window with short 90-degree returns

Application

Angle calculations

Gallery

See also