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Home Exterior Anatomy

Talk to your general contractor like a pro with this home exterior terminology guide. It's hard to know what you are paying for when you don't know the lingo. With this guide, you can talk to your GC with an educated vocabulary. We've included the most common words that home exterior companies will use with you, that you'll need to know. Don't ever hesitate to ask questions if your GC uses a term you don't recognize. This basic diagram might help you understand, but here's a longer list of terms to dive deeper into the language of home exteriors.

Walls, Siding, Roofing:

Batten- Thin vertical strips that cover the seams of vertical siding panels

Beveled Siding- AKA Clapboard, a type of siding that has a thick bottom and thin top, overlapping for water resistance

Channel- Corners and other places that require trim. J channel or F Channel are terms used commonly for this.

Dutchlap- AKA Shiplap- the piece of trim that is placed below the roof line after the siding is installed.

Fascia Board- Boards that cover the end of the rafter of a roof, closing it in and finishing the roof

Flashing- A strip, usually aluminum that is used to deflect water, placed behind siding and trim pieces to protect the backer board.

Gable- triangular section of usually siding between the roof ridges.

Insulation- a layer of wool or reflective foil that goes inside the walls to keep heat in.

J Channel- Used for trimming around around window and doors etc. F Channel is used to slide into soffit to hold it onto the house. Both allow you to make 90 degree turns with siding.

Lap- the place where two pieces of trim or siding panels overlap each other

Shake- A Shingle/siding piece that is split form a log producing a mixture texture. There are also vinyl shakes that are made to replicate this log split texture.

Sheathing- The first layer of outer wall covering nailed to the studs. This is a common word used and important to understand because often times sheathing repair is necessary when completing a siding replacement job.

Soffit- material on outer edge overhang of the rood bridging the gap between the siding and roofline- also known as eaves.


Windows can be hard to understand if you don’t have previous window knowledge. So there are a lot of terms to understand when purchasing or repairing windows. Know what your talking about and not getting ripped off with this list. As always, ask if you don't understand something.

Awning Window- A Window that is hinged at the top and opens outward from the bottom with a manual crank or push.

Bay window- Three or more window units that project outward from the wall.

Bow Window- a composite of four or more window units in a radial formation

Brickmould- A wooden trim piece that covers the gap between the window frame and the exterior of a building.

Casement window- hinged on the top or bottom and opens outward manually with a crank- includes awning windows

Casing- Decorative strips surrounding a window opening on the inside of the frame

Clad window- wood on the interior, but a more sturdy exterior material, often aluminum or fiberglass

Coil, or coil stock- a sheet usually pre-finished aluminum, generally 12 to 20 inches wide on a 50 foot roll used for external covering and trim

Composite- a solid material composed of two or more substances

Double hung- when a window has two movable portions that operate independently.

Egress- A window in a basement large enough to be used as an emergency exit

Frame- Lining of the window opening between the sash and siding/wall.

Fixed window- AKA picture window, a window that isn't operable

Flashing- material installed to shed water away from joints, usually metal.

Glass stop- AKA glazing bead- removable piece of trim that fastens the glass in place and seals it.

Glazing- a pane of glass that is treated and sealed

Grilles- AKA Muntins- the decorative dividers on the glass of the window

Infiltration- Describes the tendency of a window to allow air or water to move into or out of the building

Jamb- Groove that allows the window sashes to slide into place

Lift- the handle attached to an operable window

Lintel- the structural beam over a window (or door)

Low E- Low Emissivity- a common glass treatment that reflects heat, keeping heat in or out of the house depending on weather.

Obscure Glass- one of several types of specialty glazing that are textured for privacy or decoration.

Sash- Inner frame piece that holds in the glass

Shim- a slice of material for filling and leveling frames and other hardware

Solar Heat Gain Coefficient- The amount of solar radiation let through the window from outside in. The lover the SHGC the less heat and light is let through.

Tempered Glass- often known as safety glass due to the way it’s been treated making it up to 4 times stronger.

Weather stripping- a narrow strip of material places between window sashes to keep out rain.


Many of the door and window terms are interchangeable so some of those we didn't include here. For example both have frames and the concept is the same. So if you purchase a door and they use one of the terms listed under windows, you can apply that to your door conversation as well.

Double acting- a door with glass panes through it's length

In-swing- a door that opens inward

Mull post- the part of the door frame between the door and the side lite

Multipoint lock- one handle that locks the door in multiple places.

Out- Swing- a door that opens to the exterior

Panel- the parts of the door that is raised or sunk in the rest of the door to create texture or depth

Pre-hung: a full door unit including the frame, jamb, sill and moulding that is already hinges.

Roller- a mechanism located at the bottom of a sliding door that gives the door the ability to slide.

Sidelights- Tall narrow, usually fixed glass panels that are attached on either side of the door frame.

Sill- the bottom of the frame

Storm Door- a second door installed on the exterior door to provide more insulation during bad weather and ventilation during nice weather.

Sweep- an energy efficient and weather resistant system at the bottom of the door that forms a seal against air and water.

Threshold- a decorative component that lies at the bottom of a sliding or hinged glass that serves as a transition from the door sill to the interior flooring.

Thumbturn- the component of a door that extends or retracts with a dead bolt or latch bolt by grasping with the thumb and fingers turning.

Transom- the fixed glass panel that is installed above the door.

Have further questions? Call Z Double B at 303-997-8168 or email us at You can also visit our website to request an appointment at

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