Home Improvement Glossary

Argon Gas
Argon is a colorless, safe, odorless, non-flammable, non-toxic, inert gas that is used between the glass panes of an insulated Low-E glass unit as an insulation buffer.
Asphalt
A waterproofing coating put on roofing materials during manufacturing to improve durability.
Back Surfacing
Powdered mineral dust applied to the back side of shingles to keep them from sticking and make installation of shingles easier.
Base Flashing
The flashing which is attached to and/or resting on the deck to channel the flow of water onto the roof covering to ensure even drainage.
Bay Window
A three window composite, usually with a large center fixed unit and two flanking units at 30°,45° or 90° degree angles to the wall which create an alcove effect. A bay window is a great addition to a home and makes a profitable home improvement project.
Beading
The narrow, half-round molding which spans the edge of siding.
Beveled Exterior
An angled extension on the frame that used to improve the lines and appearance of a window and which adds an visually pleasing dimension to the window exterior.
Block Frame Window
Used when replacing the wood sash of an old double hung wood window.
Bow Window
A composite of four or more window units in a bow or radial formation.
Bundle
A package of shingles. There are 3, 4 or 5 bundles per square.
Butt Eedge
The lower edge of the shingle tabs
Fiberglass
A polymer matrix composite material with embedded glass fibers. May be used as a diffusing material in sheet form, or as a standard sash and frame element.
Finish
Texture/gloss level of a siding panel. For fiber cement, this refers to the coating used to finish the siding. Usually an opaque paint; solid or semi-transparent stain.
Fixed Window
Non-venting or non-operable window. Also known as picture window.
Flashing
A thin strip of metal or synthetic material that diverts water away from a window or skylight.
Frame
The enclosure in which window sash or door panels are mounted.
Frieze
The horizontal member connecting the top of the siding with the soffit.
Gable
The portion of the roof above the eave line of a double-sloped roof.
Gable Roof
A roof containing sloping planes of the same pitch on each side of the ridge. Contains a gable at each end.
Gambrel Roof
A roof containing two sloping planes of different pitch on each side of the ridge. The lower plane has a steeper slope than the upper. Contains a gable at each end.
Glazing
Glass panes in a window or door; the act or process of fitting with glass.
Glazing Bead
A sealing plastic or wood strip applied to the window sash around the perimeter of the glass.
Glazing Stop
The part of the sash or door panel which holds the glass in place.
Gutter
A trough that directs water from the eaves to the downspouts.
Hanger
A Flat strap installed under the roof material that holds up the horizontal section of the gutter.
Head
The main horizontal member forming the top of the window/door frame.
Header
A horizontal framing member placed over the rough opening of a window to bear the weight of wall or roof.
Hopper
A window unit that the top of the sash swings inward.
Ice Dam
A Hazardous condition at the lower roof edge caused by the thawing and re-freezing of melted snow on the overhang which then forces water up, under and around shingles, causing leaks and long term roof damage.
Insulating Glass
A combination of two or more panes of glass with a hermetically sealed air space between the panes of glass. This space may or may not be filled with an inert gas, such as argon.
Jamb
The main vertical members forming the sides of a window or door frame.
Lineal
Molding of various widths used to trim door and window openings at the jambs. Also referred to as:box post, window and door surround.
Lift
A handle or grip installed on the bottom rail of the lower sash of a double-hung window to make it easier to raise or lower the sash.
Light or Lite
Glazing framed by muntins and/or sash in a window or door.
Lintel
A horizontal member above a window or door opening that supports the structure above.
Low-E Glass
A common term used to refer to glass which has low emissivity due to a film or metallic coating on the glass or suspended between the two lights of glass to restrict the passage of radiant heat.
Masonry Opening
The space in a masonry wall left open for windows or door.
Mullion
A wood or metal part used to structurally join two window or door units.
Muntin
Applies to any short or light bar, either vertical or horizontal, used to separate glass in a sash into multiple lights. Also called a windowpane divider or a grille.
Muntin Bar
Any small bar that divides a windows glass. Also called a grille or windowpane divider.
Nail Hem
The top edge of a siding panel, where it is nailed to a wall.
Overhang
That portion of the roof structure that extends beyond the exterior walls of a building.
Overlap
Area where two pieces of lap siding are overlapped. This dimension is usually 1 1/4".
Panel Projection
The section of siding that projects from the wall. As a rule of thumb, a larger panel projection creates a more pronounced shadow line.
Picture
Non-venting or non-operable window. Also know as a fixed window.
Pitch
The degree of roof incline expressed as the ratio of the rise, in feet, to the span, in feet.
Profile
Side view of a siding or soffit panel.
Rake
Trim members that run parallel to the roof slope and form the finish between the wall and a gable roof extension.
Rail
The top and bottom horizontal members of the framework of a window sash.
Ridge
The uppermost, horizontal external angle formed by the intersection of two sloping roof planes.
Rise
The vertical distance from the eaves line to the ridge.
Rough Opening
The framed opening in a wall into which a window or door unit is to be installed.
R-Value
Resistance to thermal transfer or heat flow. Higher R-value numbers indicate greater insulating value.
Pane
A framed sheet of glass within a window.
Sash
A single assembly of stiles and rails made into a frame for holding glass.
Sash Lift
A protruding handle screwed to the inside bottom rail of the lower sash on a double-hung window.
Seat Board
A flat board cut to fit the contour of a bow or bay window and installed between the sills and the flat wall surface, providing a seat or shelf space.
Shadow Line
The shadow pattern cast by a particular siding in the sunlight. Shadow line is influenced by the style and panel projection of the siding.
Shims
Wood wedges (often wood shingles) used to secure the window or door unit in the rough or masonry opening in a square, level and plumb position during and after installation.
Sidelites
Narrow fixed units mulled or joined to door units to give a more open appearance.
Sill
The main horizontal member forming the bottom of the frame of a window or door.
Simulated Divided Lite
A method of constructing windows in which muntins are affixed to the inside and outside of a panel of insulating glass to simulate the look of true divided light.
Single Glazing
Use of single panes of glass in a window. Not as energy-efficient as double glazing.
Single-hung Window
A double-hung type of window in which the top sash is fixed or inoperable.
Cam Lock and Keeper
The mechanisms which pull the sash together when placed in the locked position.
Casement Window
A window unit in which the single sash cranks outward, to the right or left.
Casing
Molding of various widths, thickness and shapes applied to the framework of window and door units.
Caulk
A mastic compound for filling joints and sealing cracks to prevent leakage of water and air, commonly made of silicone, bituminous, acrylic, or rubber-based material.
Caulking
To fill a joint with mastic or asphalt cement to prevent leaks.
Clapboard
A thin, narrow board with one edge thicker than the other, used as siding. CertainTeed siding brands offer clapboard-style siding in different exposures, several different textures, and even different panel projections.
Collar
Pre-formed flange placed over a vent pipe to seal the roof around the vent pipe opening. Also called a vent sleeve.
Conduction
Energy transfer from one material to another by direct contact.
Convection
Heat transfer by currents that flow from a warm surface to a colder one.
Deck
The surface installed over the supporting framing members to which the roofing is applied.
Dormer
A space which protrudes from the roof of a house, usually including one or more windows.
Double-hung Window
A window unit that has two operable sashes which move vertically in the frame.
Downspout
A pipe for draining water from roof gutters. Also called a leader.
Drip Cap
A molding placed on the top of the head brickmold or casing of a window frame.
Drip Edge
A non-corrosive, non-staining material used along the eaves and rakes to allow water run-off to drip clear of underlying construction.
Double or Dual Glazing
Use of two panes of glass in a window to increase energy efficiency and provide other performance benefits.
Dutchlap
A beveled-edge siding panel that was popularized by early American settlers.
Eaves
The horizontal, lower edge of a sloped roof.
Emissivity
The relative ability of a surface to radiate heat.
Exposure
The width of each "board" of siding. Also called a reveal.
Extrusion
A form produced by forcing material through a die. Most window frames are clad with extruded vinyl or aluminum.
Fascia
Architecturally, "fascia" refers to a flat, horizontal band. A flat board that runs horizontally along the eaves of a roof, typically capping the ends of the roof rafters to give the roof edge a more finished look and provide a base for attaching gutters.
Fenestration
An architectural term referring to the arrangement of windows in a wall. From the Latin word, "fenestra," meaning window.
Slider Window
Both sashes slide horizontally in a double-sliding window. Only one sash slides in a single-sliding window. Ventilation area can vary from a small crack to an opening of one-half the total glass area. Screens can be placed on the exterior or interior of the window unit.
Slope
The degree of roof incline expressed as the ratio of the rise, in inches, to the run, in feet.
Soffit
Usually the underside of an overhang or eaves.
Stile
The main vertical members of the framework of a sash.
Strikeplate
Protects the jamb from the hardware latch on a door. Covers the latch and deadbolt.
Square
Unit of measure for siding equal to 100 square feet (or a 10-foot by 10-foot wall section).
Stool
An interior trim piece on a window which extends the sill and acts as a narrow shelf.
Stop Molding
A molding used to hold, position or separate window parts.
Tempered Glass
Glass manufactured to withstand greater than normal forces on its surface. When it breaks, it shatters into small pieces to reduce hazard. Standard on all doors and large fixed windows.
Thermal Break
The addition of a thermal insulating material between two thermally conductive materials.
Threshold
The bottom part of the door frame, i.e. the area you step on when entering or exiting through the doorway.
Transom
A small window that fits over the top of a door or window, primarily for additional light and aesthetic value.
True Divided Lite
A term which refers to windows in which multiple individual panes of glass or lites are assembled in the sash using muntins.
Underlayment
Asphalt saturated felt used beneath roofing to provide additional protection for the deck.
Valley
The internal angle formed by the intersection of two sloping roof planes.
Vent
Any outlet for air that protrudes through the roof deck such as a pipe or stack. Any device installed on the roof, gable or soffit for the purpose of ventilating the underside of the roof deck.
Vent Unit
A window or door unit that opens or operates.
Vertical Siding
Also referred to as "panel siding", this rectangular shaped siding is typically manufactured in 4 x 8, 4 x 9 or 4 x 10 sizes. Vertical siding is never overlapped. Solid vinyl soffit can also be used as vertical siding.
Vinyl
A plastic material used for cladding or entire window units.
Weatherstripping
A material or device used to seal the openings, gaps or cracks of venting window and door units to prevent water and air infiltration.
Head Jamb
Groove at the top of the window which allows the window sashes to slide into place and seat inside the window frame.
Upper Sash
The top portion of the window comprised of a pane of glass set inside a frame. Is fixed in a single hung window and slides up and down in a double hung window.
Glass Pane
In the window shown at right there are two panes of glass, one in the top sash and one in the bottom sash.
Side Jamb
Grooves in window that allows the window sashes to slide up and down or side to side
Trim
The trim extends beyond the end of the window frame on the outside of the window. This allows the window to fit flush with the exterior wall when the window in installed.
Stop
A wood trim member nailed to the window frame to hold, position or separate window parts. The stop is often molded into the jamb liners on sliding windows.
Lower Sash
The bottom portion of the window comprised of a pane of glass set inside a frame. Is fixed in a single hung window and slides up and down in a double hung window.
Sill
Located at the very bottom of the window, the sill is usually sloped to allow water to run off the bottom of the window in rain or during cleaning.
Flush Fin window
A replacement window with flush fin is used when replacing an existing aluminum sliding window. This is the most commonly used replacement window type.
Block Frame window
A block frame window is used when replacing the wood sash of an old double hung wood window.
Sloped Sill Adapter
A sloped sill adapter is used to cover the gap between the old sloped sill window and the new block frame window. It adapts a new window to the existing sloping sill.