What is a protruding window sill?

Author: Dr. Henderson Gutmann  |  Last update: Monday, August 4, 2025

A window sill projects into the room further than any other side of your window. A window may have a recess and a sill. If you're unsure, look at your window from the side. Does the bottom of your recess stick out further than the top? If the answer is yes, you have a sill.

What is a protruding sill?

We sometimes hear the term sill in reference to the window recess, but we consider a window sill any protrusion from the bottom of the window opening. Sometimes referred to as a ledge or shelf, we consider it a sill if it projects past the edge of the wall or trim.

What is a protruding window called?

Bay window is a generic term for all protruding window constructions, regardless of whether they are curved or angular, or run over one or multiple storeys. In plan, the most frequently used shapes are isosceles trapezoid (which may be referred to as a canted bay window) and rectangle.

What are the different types of window sills?

Standard window sill materials are wood, particleboard, PVC, stone, and tile. A unique window sill is a great way to introduce additional color or pattern into your home, and to make a design statement.

How far should a window sill protrude?

Hold a scrap piece of your window trim casing against each window side, and at your reveal mark. Mark a reference line on the wall, on each side of the window. Determine your window sill “horn” overhang. I typically use ¾” for an overhang.

How to cut a Window Sill in a bay window. ready for insulated plasterboards

Why do window sills stick out?

It helps stabilise and absorb level changes on your openings, keeps water outside of your home and seals the wall cavity on the foot of your windows. Another key protective trait of sills is how their overhang keeps your glass from the risk of being shattered by, let's say, someone tripping in your living room.

How much does a window sill stick out?

A general assumption is that indoor window sills should not stick out from the wall more than 60% of their length.

What is the difference between a window sill and a window ledge?

A window sill, also known as a window ledge or window bottom, is the shelf-like, flat piece of the window trim found at the base of the window. Window sills are important to the design and functionality of the window. Despite common belief, the window sill is found on the outside of the home.

What is a window sill you can sit on called?

A window seat is called a window bench, window nook or alcove. It is a mini sofa without a backrest for filling the gap of a window. Window benches are a great way to utilize extra or unused space for seating.

Do modern homes have window sills?

They're such a vital part of every kind of modern dwelling that you'll even see them in most manufactured housing units. About the only time you'll find a place that lacks window sills of some sort is if a contractor is currently in the process of redoing the walls.

What do you call windows that protrude?

Bay and garden windows both protrude from the home's exterior. While bay windows form a bevel between 25 and 45 degrees, garden windows are much boxier. They stick out at a 90-degree angle on four sides, with a top panel that slopes to allow precipitation to run off.

What kind of window juts out?

Bay and bow windows are combination windows that protrude outward from the home. Both windows can add character, natural light and open any room. They also commonly give great external views from inside due to the large amounts of glass.

What do you call the part of the house that sticks out?

by Shubham Chinchalkar April 24, 2023. The overhang or projection at the edge of a roof is known by several names, including eave, rake, and fascia. These elements not only add visual interest to a home's exterior but also serve important functional purposes.

What is the difference between window sill and threshold?

The sill acts as a structural element, while the threshold protects the sill and the home's interior from water. Read on for what you need to know to differentiate between a door sill and a threshold.

What is an intrusive sill?

In geology, a sill is a tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or along the direction of foliation in metamorphic rock. A sill is a concordant intrusive sheet, meaning that it does not cut across preexisting rock beds.

Are window sills out of style?

In modern designs, many home builders are eliminating the decorative window sill. They are using flush stools effectively covered up by the window trim or apron. However, you don't have to accept this method for your home.

What is a pocket sill window?

A pocket sill is a design which allows the window sash, or moveable portion of the window, to rest down inside of a pocket created in the frame. The result is that when the window is fully closed, the bottom rail of the sash is mostly hidden and you get more visible glass.

What's the name for a window that sticks out on the outside of a property?

A bay window projects out from the exterior wall line and extends to the floor. Many Victorian and Edwardian houses feature bay windows as a focal point for the living room at the front of the house. Houses at the coast also benefit from the extra panoramic views from the projecting window.

What is a stooled window sill?

Stooled cills

The purpose of the stooling is to give a flat level surface for the brickwork to sit on. If there were no stooling, a large unsightly joint would be required to accommodate for the slope on the cill. This cill may be made to sit flush with the wall or, more usually, have an overhang of approximately 50mm.

What does a window sill sit on?

A window sill in the most general sense is a horizontal structural element below a window opening or window unit in masonry construction or framed construction and is regarded as part of the window frame. The bottom of a window frame sits on top of the window sill of the wall opening.

What is the trim under a window sill called?

Apron – A piece of decorative trim installed beneath the railing or sill.

What is a window reveal?

In its simplest form, a window reveal is the timber surround of the window unit; you might refer to it as the windowsill (although technically, only the bottom horizontal component of a window is called a 'sill').

What is a tongue on a windowsill?

Adding a tongue to a window board simply means we will remove a specified amount of material from the underside of the window board at the back edge to ensure the window board will fit flush over any debris below the window.

Is it expensive to replace a window sill?

Window sill replacement costs an average of $400, and most homeowners pay between $150 and $700 to have a window specialist carry out the work. You could pay as little as $100 to replace an aluminum or vinyl sill on a small hopper window or as much as $1,100 to replace a wooden sill on a larger bay window.

What is the window that sticks out of building?

An oriel window is a form of bay window which protrudes from the main wall of a building but does not reach to the ground. Supported by corbels, brackets, or similar cantilevers, an oriel window generally projects from an upper floor, but is also sometimes used on the ground floor.

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