Glossary of House Building Terms

Use this glossary to look up residential architecture and construction terms you may encounter while reviewing blueprints, comparing house designs, or preparing to build. Jump to a letter BCDEFGHJKLMNPQRSTVW 84 terms B Baseboard A molding that runs around the perimeter of a room at the base of the walls. It covers expansion gaps, protects walls from scuffs, and creates a clean transition between the flooring and wall surface. Base Cabinet A storage cabinet that rests on the floor, typically with a toe-kick and countertop. Base cabinets support countertops, sinks, and some appliances while providing storage through doors, drawers, or shelves. Batten A narrow strip of wood, metal, or composite material used to cover joints, secure panels, or add detail. Battens are commonly seen in board-and-batten siding, wall treatments, and roof assemblies. Bay Window A window structure that projects outward from a building’s main walls, creating a small nook or alcove inside. It typically has a central window flanked by two angled side windows. See window design options for a new house plan. A bay window projects from the stone exterior of this home. Beam A horizontal structural member that carries loads across a span and transfers weight from floors, ceilings, or roofs to walls, columns, or posts. Beams may be made of wood, steel, or reinforced concrete. Bearing Wall A wall that carries a structural load from the floors or roof above. Removing or altering a bearing wall can affect the structure and usually requires review by a qualified professional. Why it matters: Bearing walls affect open layouts and the feasibility of later modifications. Bifold Door A door made of hinged panels that fold together as the door moves along a track. Bifold doors are often used for closets because they need less clear floor area than a swinging door. Birdsmouth A notch cut into the bottom of a roof rafter or timber so it can rest securely on the top plate of a wall. The cut helps align the rafter and transfer roof loads to the wall. Blueprint – Floor Plan A scaled, top-down drawing showing the arrangement of rooms, walls, doors, windows, and major fixtures. Learning how to read a floor plan helps you evaluate circulation, room relationships, and furniture placement. Why it matters: Floor plans help buyers compare room flow, dimensions, privacy, and everyday livability. Bow Window A curved window assembly made from four or more window units. The connected sections project from the main wall in a gentle arc, bringing in light and creating a shallow interior nook. Box Window A three-sided window projection similar to a bay window. Its side panels are perpendicular to the main wall, and its center panel runs parallel to it, creating a squared rather than angled projection. The box window is highlighted to the right of the garage. Bridging A short framing member installed between studs, joists, or rafters to keep them aligned and help distribute loads. In wall framing, similar pieces may be called blocking or fire blocking. Read more about the framing used to build a house. C Casing The finished trim that surrounds a door or window opening and covers the joint between the frame and the wall. See examples of architectural trim and how it is used. Casement Window A window hinged on one side that opens outward like a door, usually with a hand crank. When closed, the sash presses against the frame to form a tight seal. Cathedral Ceiling A high ceiling with two sloping sides that generally follow the roofline and meet at a central ridge. Cathedral ceilings increase the perceived volume of great rooms and other main living spaces. A cathedral ceiling follows the roofline above this great room. Chair Rail A horizontal molding installed partway up a wall. Originally used to protect plaster from chair backs, it is now also used to divide wall finishes or add traditional architectural detail. A chair rail separates the upper and lower wall finishes in this dining room. (Plan #163-1020) Coffered Ceiling A ceiling divided into a grid of recessed panels by intersecting beams or trim. Coffers add depth and rhythm to a room and can help define an open living area. Read more about how ceiling design affects a home. A coffered ceiling defines the family room within an open layout. Construction Documents (CDs) The coordinated set of drawings and notes used to permit and construct a home. Depending on the plan package and local requirements, the set may include floor plans, elevations, sections, structural information, and other technical details. Why it matters: Construction documents are used for permit review, estimating, and building. Crown Molding A decorative molding installed where a wall meets the ceiling. Its profile softens the transition between the two surfaces and is most often associated with traditional interiors. Crown molding finishes the wall-to-ceiling joint in this dining room. D Dormer A roofed projection that extends through a sloped roof and usually contains a window. Dormers bring daylight and headroom to upper floors or attic spaces and can change the character of the exterior. Three dormer windows bring light into the upper floor. (Plan #206-1015) Dropped Ceiling A ceiling plane built below the structure above it. A dropped ceiling may conceal ductwork, plumbing, or wiring, or it may be used to create a lower, more defined area within a larger room. Dutch Gable Roof A roof that combines a hip roof on the lower portion with a gable above. Also called a gablet roof, it adds attic space and a gable face while retaining hip roof planes on all sides. E Eaves The lower edges of a roof that project beyond the exterior walls. Eaves help direct water away from the siding and foundation and may include the fascia, soffit, and gutter. Blue outlines identify the projecting eaves on this home. Edge Flashing Metal trim installed along the edge of a roof to direct water away from the roof deck and fascia. At the eave, it is commonly called drip edge. Egress A safe, code-compliant means of leaving a building. Building codes establish minimum clear-opening dimensions and other requirements for egress doors and windows, including those in sleeping rooms. Elevation A flat, scaled view of one exterior side of a home. Exterior elevations show height, roof shape, window and door placement, exterior materials, and other architectural details. Why it matters: Elevations explain the home’s exterior composition and provide information used during construction. A blueprint sheet showing multiple exterior elevations of one house design. F Fascia A horizontal board attached to the ends of rafters or roof trusses at the roof edge. Gutters are commonly fastened to the eave fascia; fascia at a gable end is called gable fascia. Fixtures Items attached to a building and intended to remain in place, such as sinks, tubs, light fixtures, water heaters, and furnaces. The exact legal meaning can vary by contract and jurisdiction. Footing A widened concrete base that spreads the load of a foundation wall, bearing wall, pier, or column over the soil. Footing size and reinforcement depend on the loads and site conditions. Frieze A horizontal trim board placed near the top of an exterior wall, where the wall surface meets the soffit or eave. G Gable The triangular portion of an exterior wall between the sloping sides of a pitched roof. Its shape, windows, vents, and trim often contribute strongly to the front elevation. The highlighted wall section is a front-facing gable. Gable Roof A roof with two sloping sides that meet at a ridge, forming a triangular gable at one or both ends. It is a straightforward roof form used across many architectural styles. Why it matters: Gable roofs shed water efficiently and often provide usable attic volume. Gambrel Roof A symmetrical roof with two slopes on each side. The upper slope is shallower, and the lower slope is steeper, creating more room beneath the roof than a typical gable form. A gambrel roof creates a broad upper story on this traditional home. Girder Truss A specially designed truss that carries the ends of other trusses. It is often used where roof framing changes direction or spans an opening. Gull Wing Roof A roof with two slopes on each side of a ridge, arranged opposite a gambrel: the upper section is steeper, and the lower section becomes shallower toward the eaves. The outlined roof planes show the gull wing profile on this mid-century modern home. Gutters Channels installed along roof edges to collect rainwater and direct it to downspouts. Properly sized and maintained gutters help limit water exposure at the siding and foundation. H Half-Hip Roof A roof with a shortened hip at the top of a gable end. Also called a clipped gable or jerkinhead roof, it combines a mostly gabled profile with a small sloping section near the ridge. This home uses clipped gables, also called half-hips, at several roof ends. Hearth The noncombustible floor area at the base of a fireplace, extending into the room. A hearth may be flush with the floor or raised. See current fireplace design trends. Hip Roof A roof that slopes down toward the exterior walls on all sides. Because there are no full-height gable ends, the eaves typically remain level around the house. A low hip roof slopes toward all four sides of this ranch home. HVAC Heating, ventilation, and air-conditioning systems and equipment. HVAC design affects comfort, energy use, equipment placement, and the space needed for ducts or other distribution systems. Review these heating and cooling considerations. J Joist A horizontal framing member installed at regular intervals to support a floor or ceiling. Joists transfer loads to bearing walls, beams, or girders. K Knee Wall A short wall commonly found where a sloped roof meets an upper floor. It may close off the low space beneath the roof and can create storage along the edges of a bonus room or finished attic. Knee walls create low sidewalls beneath the sloped ceiling of this bonus room. (Plan #141-1239) L Landing A level platform at the top, bottom, or midpoint of a stair run. Landings provide a place to change direction and are sized according to stair design and code requirements. Lites Individual panes or visually divided areas of glass in a window or door. Muntins or grilles may separate true panes or create the appearance of multiple lites. M Mansard Roof A four-sided roof with two slopes on each side. The lower slopes are steep, often containing windows or dormers, while the upper slopes are much shallower and may be difficult to see from the ground. Modification A custom change made to an existing house plan, such as moving walls, resizing rooms, changing the garage, or adjusting the exterior. The designer or a qualified local professional prepares the revised drawings. Why it matters: A modification personalizes an existing design without starting with a completely custom plan. Monolithic Slab A concrete slab and its thickened perimeter footings poured as one continuous placement. Reinforcement and thickened areas are designed to carry wall and building loads. N Newel A substantial vertical post that anchors a stair railing at the beginning, end, landing, or change in direction. Newels provide support for the handrail and balustrade. A square newel anchors the handrail at the bottom of the stair. P Pier Foundation A foundation system that supports a structure on individual piers rather than a continuous wall. Piers may be concrete, masonry, steel, or treated wood and must be designed for the loads and soil conditions. Pillar A vertical element that supports a beam, roof, arch, or other load. Pillars may be wood, masonry, concrete, or metal and can also contribute decorative character to a porch or interior. Heavy timber pillars support beams in this Craftsman interior. (Plan #163-1027) Plinth Block A decorative block installed at the bottom of a door casing where it meets the baseboard. It creates a finished transition between trim pieces with different profiles or thicknesses. Pocket Door A sliding door that disappears into a framed cavity in the wall when open. It saves the floor and wall clearance required by a swinging door but needs unobstructed wall space for the pocket. Pony Wall A short wall that does not extend to the ceiling. Depending on the context, it may define spaces, support a counter or railing, or extend a stepped foundation wall to the floor framing. A pony wall separates the stair from the adjacent living area. (Plan #161-1048) Q Quoin A masonry unit or applied trim detail used to emphasize the outside corner of a building. Quoins may be structural in historic masonry or purely decorative in newer construction. The highlighted corner blocks are decorative quoins. (Plan #153-1868) R Rafter An inclined roof-framing member that extends from the eave toward the ridge. Rafters support the roof sheathing and transfer roof loads to exterior walls, beams, or other supports. Exposed rafters frame the vaulted great room of this rustic home. (Plan #161-1076) Rebar Steel reinforcing bar embedded in concrete to improve its tensile strength. The size, spacing, placement, and required concrete cover depend on the structural design. Reproducible License Permission to build the same house plan more than once, subject to the terms of the license. A standard plan purchase usually grants a single-build license unless stated otherwise. Why it matters: Builders and developers must confirm build rights before reusing a design. Ridge The highest horizontal line of a roof, where two sloping roof planes meet. In framed roofs, a ridge board or structural ridge beam may run along this line. Right-Reading Reverse A mirrored version of a house plan in which the layout is flipped left to right while the text and dimensions remain readable. It is different from a simple mirror-reverse print, where notes also appear backward. Why it matters: A right-reading reverse can improve driveway placement, views, solar orientation, or the fit on a particular lot. Rim Joist A framing member installed around the perimeter of a floor system, perpendicular to the floor joists. It closes the joist ends, helps keep them aligned, and supports the edge of the floor assembly. S Saltbox Roof An asymmetrical gable roof with one long, low rear slope and a shorter front slope. The off-center ridge is a defining feature of traditional saltbox houses. Section View A vertical cut-through drawing that shows relationships not visible in a floor plan, such as floor and ceiling heights, roof structure, stairs, foundations, and the connections between building levels. Why it matters: Section drawings help explain volume, structure, and concealed construction. Sheathing Panels or boards fastened to wall, roof, or floor framing to create a continuous surface and help brace the structure. Material selection depends on the assembly and performance needs. Compare exterior wall sheathing options. Shed Roof A roof made from one sloping plane. A shed roof may cover an entire small structure or be combined with other roof forms over additions, porches, and dormers. Slab Foundation A foundation in which the home’s lowest floor is a concrete slab placed on or near grade. It may use separate stem walls and footings or be poured as a monolithic slab. Compare slab, crawlspace, and basement foundations. Slider Door A door with one or more panels that move horizontally along a track. In a typical two-panel patio door, one panel slides in front of a fixed panel. A sliding barn-style door closes the pantry without using swing space. Soffit The finished underside of an architectural element. Exterior soffits close the underside of roof overhangs; interior soffits may conceal ducts or fill the space above cabinets. Split-Level A house in which adjoining sections are set at different floor heights and connected by short flights of stairs. The arrangement can separate living zones while keeping the overall footprint compact. A split-level home with staggered floor and roof heights. (Plan #126-1083) Stair Riser The vertical face between two stair treads. Building codes regulate riser height and consistency because uneven risers can create a tripping hazard. White stair risers contrast with the wood treads. Stem Wall A short foundation wall built between a footing and the framed floor or slab above. Stem walls raise the structure above grade and transfer loads to the footing. Stepped Foundation A foundation wall or footing built at a series of different elevations to follow sloping ground. Each step must be detailed to maintain proper support and load transfer. Stile A vertical member in the frame of a cabinet door, passage door, or face frame. Horizontal members between the stiles are called rails. Stringer An inclined structural member that supports stair treads and risers. A stair may use cut stringers, housed stringers, or a central steel or wood stringer. An angled stair stringer supports the treads and risers. (Plan #161-1048) Stud A vertical framing member used to build walls and partitions. Stud size, spacing, species, and grade depend on the wall height, loads, and building requirements. T Termite Flashing Sheet metal or another approved barrier installed at vulnerable transitions between a foundation and wood framing to help block concealed termite entry. Requirements vary by climate and local code. Top Plate A horizontal framing member installed across the tops of wall studs. It ties the wall together and distributes loads from ceiling joists, rafters, or trusses. Transom Window A window installed above a door or another window. Transoms bring daylight deeper into an entry or room and may be fixed or operable. A transom window brings light above the main entry. (Plan #146-2810) Trimmer A shortened framing member used beside an opening or around an interruption in a floor or roof system. At a wall opening, a trimmer stud supports the end of the header. Truss An engineered assembly of connected members designed to span a distance and support roof or floor loads. Roof trusses are commonly triangular and use internal web members to distribute forces. Truss Chord A main outer member of a truss. The top chords generally follow the roof slope, while the bottom chord often supports the ceiling below. V Valley Flashing Flashing installed where two sloping roof planes meet in an inside angle. It directs concentrated runoff down the valley and helps prevent water from reaching the roof deck. W Wall Cabinet A cabinet mounted to the wall, usually above a base cabinet or counter. Unlike a base cabinet, it has no toe-kick or countertop. Wall cabinets provide storage above the bathroom countertop. (Plan #153-2019) Webbing – Truss The internal diagonal and vertical members that connect the top and bottom chords of a truss. The web pattern distributes loads through the assembly. Window Sill The horizontal member at the bottom of a window opening. An interior stool may project into the room, while the exterior sill is shaped or flashed to direct water away. The highlighted horizontal member is the interior window sill.