Definitions & sketch of the 60 basic components of a house structure
HOUSE PARTS, DEFINITIONS - CONTENTS: Home Inspection Definitions & Terms - Glossary of more than 60 basic parts of a house and its structure: part names, where they are found. Home inspection definitions. List of home inspection terms. Home inspection terminology also defines the limits and scope of a home inspection
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
Names & Definitions of the Parts of a House:
This article provides a glossary of the main parts of a house and house structure and we give definitions of common home inspection terms used during home inspections or in home inspection reports. Terms defined here may also appear in home inspection standards and home inspection licensing laws.
This is a public, consumer information document containing a glossary
defining some key terms regarding home inspectors in the United States
Our page top sketch was published by US DHEW and also by New York State in 1955 (Basic Housing Inspection) or earlier.  A key to the numbered items in this house parts list is just below at Glossary of Common House Parts.
Because we have found the the page top sketch (US DHEW and New York State 1955 or earlier ) published in several forms with and without a consistent key to the numbered house parts or even consistent numbers, we have made up our own glossary list keyed to that sketch - below.
CONTACT us with suggested changes or additions to these terms and definitions.
8. Fireplace mantel - horizontal trim attached to wall above fireplace opening.
See FIREPLACES & HEARTHS
9. Hearth - flat surface in front of the fireplace, protects flooring from fire.
See Fireplace Hearth Size
10. Ridge cap or ridge vent (if present)
11. Ridge board
12. Cripple rafters or Jack rafters (between chimney and house eaves - rafters that do not extend the full distance between house eaves and the roof ridge board)
13. Rafter blocking or cross bridging, also found on floor joists and in some wall framing
14. Soffit or lookout or house eaves. The soffit is the enclosed portion of the roof that overhangs the house walls at the roof lower edges. The construction of a typical roof overhang, eave or soffit is shown in our sketch at left.
16. Roof shingles (asphalt shingles, clay tiles, slates, wood shingles, or shakes, similar materials) -
See ROOFING INSPECTION & REPAIR
17. Drip edge (shown on gable end, used at lower roof edges or eaves). The drip edge is special metal flashing intended to divert water off of the roof lower edges into the roof gutter system. Drip edges should spill into the gutter, not behind it.
ROOF FLASHING DEFECTS LIST
18. Gutter (attached over or to fascia board) to collect roof drainage and prevent it from spilling down and along the building walls (leaks) and basement (wet basements).
See GUTTERS & DOWNSPOUTS
Below we include definitions of trim found at or near the top of building exterior walls and thus (usually) lower than the gutter and soffit:
Definition of Cornice molding or cornice trim: The horizontal board running at the top of a building exterior wall is a cornice molding or cornice trim board; some buildings have a decorative cornice while more common on simple residential structures is a plain horizontal trim board.
The cornice is also described in some dictionaries as the uppermost part of an entablature. Cornice molding also is used indoors in some buildings and appears as a trim board mounted at the juncture of wall top and ceiling.
Definition of frieze board: a frieze board is a horizontal decorative board at the top of a wall or between the cornice and the wall covering; a frieze board may appear on the building exterior or on an interior wall as well. A frieze board may appear alone, without cornice molding. Thus some architects and builders may refer to the horizontal board at the top of the wall, below the soffit as simply the frieze board, omitting any discussion of (the more complex) cornice or cornice trim.
Definition of Facia board or fascia trim: The horizontal board running along the outer edge of a soffit, typically covered or mostly covered by a gutter on modern homes, is the fascia board.
Dont' confuse fascia board with cornice molding which is below the soffit and in the plane of the wall itself. On some buildings the water table trim is a bit more complex, using at least two pieces of horizontal trim: a narrow board, perhaps 1-3" in width is placed on an angle sloping away from the wall to form a drip cap atop a 6-10" wide horizontal trim board placed flat against the building.
The water table trim board is described at item 29 below.
19. Downspouts (conduct roof drainage from the gutters to a destination away from the building or into a storm drain system). See DOWNSPOUT / LEADER DEFECTS
20. Downspout leader or downspout extension (hard to see, behind that front right entry porch column)
21. Gable end and gable-end attic vent. The gable end the house wall on a conventional simple gable roof such as shown in our sketch is the triangular end wall (arrows 17, 22, 23, and 31)
See ROOF VENTILATION SPECIFICATIONS
Definition of The rake area of the roof or ends of the roof itself may overhang the gable end wall. The rake is the edge of the gable roof that runs parallel to the sloping roof edge and extends from the ridge or "peak" to the lower roof edges at the gable end walls of the home. Don't confuse "rake" or "gable end" (arrows 17, 22, 23, and 31) with "soffit" or "eaves" of a roof. The eaves are the lower edges of the roof that run parallel to the house walls under the lowest roof edges (arrows 18 and 36 in the sketch).
22. Gable end fascia. See notes at 21 above. The gable end fascia is the trim board attached to the roof edges, extending from ridge to lower roof edge, and where a rake overhang is present, covering the outermost rake rafter or barge rafter.
23. Gable end vent or attic vent at gable end (Not shown: rake intake venting may also be found at the gable ends of a home where barge rafters and framing form an overhang at these walls).
25. Wall Stud basic framing unit of wood frame construction building walls
26. Sill plate (rests atop foundation wall, nailed to rim joist and joists)
27. Wall top plate
28. Diagonal wall bracing (not present on all buildings, modern wood frame construction uses plywood or OSB sheathing to provide wall stiffness and protect against "racking" or diagonal movement in the wood framed structure)
29. Wall sheathing - showing diagonal tongue and groove boards, typically 3/4" thick; modern wall sheathing in wood frame construction uses 1/2" thick plywood or OSB sheathing products. Also see INSULATION INSPECTION & IMPROVEMENT.
Definition of Water table trim board: The horizontal board running along the bottom of a building exterior wall siding such as common on clapboard-sided homes is often called a water table trim board.
Our illustration at left shows the water table horizontal trim board on a building sided with wood clapboards. Best construction practices would include zee flashing atop this board and extending up behind the bottom clapboard just above, or a drip cap atop the water table trim board along with zee flashing.
Cornice, frieze and fascia boards and trim are described above at item 16.
31. Interior partition wall over fireplace mantel; may be plaster over solid masonry or other construction;
32. Floor joist resting on basement beam or center girder.
33. Flooring underlayment (in 1955 this was red rosin paper or 15# roofing felt). Modern floor underlayment uses at least one thickness of tongue-and groove 3/4" plywood. Where carpeting is to be installed builders may use solid-core plywood to avoid accidental punctures of the flooring through the carpeting (stiletto heeled shoes).
See FLOOR DAMAGE DIAGNOSIS
34. Subflooring (shown, diagonal tongue and groove boards) - see #33 above. Additional layers of subflooring over the base underlayment may be installed where tile is to be installed; FLOOR FRAMING & SUBFLOOR for TILE
43. Footing drain or foundation drain (perforated pipe + gravel, should extend to daylight to drain by gravity). FOOTING & FOUNDATION DRAINS
44. Poured concrete basement floor slab (floating slab atop compacted fill inside foundation wall)
45. Compacted fill (or gravel atop fill or poly on gravel on fill) below basement floor slab
46. Main girder resting on supporting posts or pockets in foundation walls (not shown but you can see a post to the right of (30). The main girder carries part of the floor joist load, typically through the center of the home. FRAMING DAMAGE, INSPECTION, REPAIR
62. Stair baluster. Balusters are the vertical supports enclosing the space between the underside of the stair railing and the stair tread upper surface. Typically spaced 4" o.c. to avoid child hazards.
Definitions of Home & Building InspectionTerms
Automatic Safety Controls
- Devices designed and installed to protect systems and components from
excessively high or low pressure and temperatures, excessive electrical
current, loss of water, loss of ignition, fuel leaks, fire, freezing, or
other unsafe conditions.
Central Air Conditioning - see Air Conditioning System Inspection Diagnosis Repair for details.
- A system which uses ducts to distribute cooling and/or dehumidified
air to more than one room or uses pipes to distribute chilled water to
heat exchangers in more than one room, and which is not plugged into an
electrical convenience outlet.
- A readily accessible and observable aspect of a system, such as a floor,
or wall, but not individual pieces such as boards or nails where many similar
pieces make up the component.
Cross Connection - see CROSS CONNECTIONS, PLUMBING for details.
- A plumbing system cross connection is any physical connection or arrangement between potable water and any
source of contamination. A cross connection risks contamination of building water piping or municipal water supply with bacteria.
Common examples of cross connections in buildings include water softeners (see HEALTH RISKS & WATER SOFTENERS) and dishwashers connected to a building drain without an air gap and water powered backup sump pump systems that use municipal water pressure and a venturi to evacuate water from a building or its sump pit (see Sump Pump Types). Leaving a garden hose outlet end in an unsanitary water source such as a garden pond is also a cross connection that may be unsanitary.
Dangerous or Adverse Situations
- Situations which pose a threat of injury to the inspector, and those
situations which require the use of special protective clothing or safety
See Safety for Building Inspectors
- Report in writing a system or component by its type, or other observed
characteristics, to distinguish it from other components used for the same
See Reports: Checklists vs Narrative
- To take apart or remove any component, device, or piece of equipment
that is bolted, screwed, or fastened by other means and that would not
be dismantled by the homeowner in the course of normal household maintenance.
- Analysis or design work requiring extensive preparation and experience
in the use of mathematics, chemistry, physics, and the engineering sciences.
See STRUCTURAL INSPECTIONS & DEFECTS for examples of non-engineering inspection of buildings and structures for visual evidence of defects or unsafe conditions.
- To go into an area to observe all visible components.
- A drain is functional when it empties in a reasonable amount of time
and does not overflow when another fixture is drained simultaneously.
See CLOGGED DRAIN DIAGNOSIS & REPAIR.
- A reasonable flow at the highest fixture in a dwelling when another
fixture is operated simultaneously. See WATER PRESSURE MEASUREMENT.
On-site Water Supply Quantity
- Water quantity is the volume of water that can be drawn from a well under normal usage rates (for private water supply systems. For municipal water supply systems the quantity of water that can be drawn is usually not limited.
But many people who ask about water "quantity" are actually concerned with the rate of flow of water . Flow rate -how fast water comes out of a faucet or shower head, depends on several variables such as pipe diameter and water pressure (see WATER PRESSURE MEASUREMENT).
If the building is served by a private well, both water quantity and flow rate may also be limited by the well itself (see WELL FLOW RATE).
- To cause systems or equipment to function. Usually during a home inspection equipment is operated just by using normal controls and switches intended for use by the occupants of the building.
Primary Windows and Doors
- Windows and/or exterior doors which are designed to remain in their
respective openings year round and not left open for the entire summer. See WINDOWS & DOORS
Readily Openable Access Panel
- A panel provided for homeowner inspection and maintenance which has
removable or operable fasteners or latch devices in order to be lifted
off, swung open, or otherwise removed by one person, and its edges and
fasteners are not painted in place. Limited to those panels which are within
normal reach or from a 4-foot stepladder, and which are not blocked by
stored items, furniture, or building components.
- Spas, saunas, steam baths, swimming pools, tennis courts, playground
equipment, and other exercise, entertainment, or athletic facilities.
- For multiple identical components such as windows and electrical outlets
-- one such component per room. For multiple identical exterior components
- one such component on each side of the building.
Roof Drainage Systems
- Gutters, downspouts, leaders, splash blocks, and similar components
used to carry water off of a roof and away from a building. See GUTTERS & DOWNSPOUTS.
- Tempered glass, laminated glass, or rigid plastic. See WINDOWS & DOORS.
- A piece of equipment or a system is shut down when it cannot be operated
by the device or control which a home owner should normally use to operate
it. If its safety switch or circuit breaker is in the "off" position,
or its fuse is missing or blown, the inspector is not required to reestablish
the circuit for the purpose of operating the equipment or system.
Solid Fuel Heating Device
- Any wood, coal, or other similar organic fuel burning device, including
but not limited to fireplaces whether masonry or factory-built, fireplace
inserts and stoves, woodstoves (room heaters), central furnaces, and combinations
of these devices. See Wood Burning Heaters Fireplaces Stoves for details.
- A component which supports non-variable forces or weights (dead loads)
and variable forces or weights (live loads). See STRUCTURAL INSPECTIONS & DEFECTS.
- A combination of interacting or interdependent components, assembled
to carry out one or more functions.
- An inspection is technically exhaustive when it involves the extensive
use of measurements, instruments, testing, calculators, and other means
to develop scientific or engineering findings, conclusions, and recommendations.
Underfloor Crawl Space
- The area within the confines of the foundation and between the ground
and the underside of the lowest floor structural component.
See CRAWL SPACE SAFETY ADVICE
ASHI Inspections are focused on in-service conditions and do not certify
compliance with building codes. But to be accurately informed and to be
able to recognize important defects in the field, ASHI inspectors may refer
to various building codes and also to other standards for purposes of training
In-service building component failures
ASHI inspectors operate in that zone of discovery between new constructing
code-compliance inspections and post-failure investigations and repair
work. Using essentially visual methods home inspectors examine both major
building components and small details which offer clues suggesting areas
where major repairs may be needed.
ASHI's Contribution to other fields Because ASHI has building
experts examining residential structures in every U.S. State and Canadian
Province, ASHI members present an opportunity to contribute to and share
data and field experience with other construction-related professional
groups and with trade associations.
What do you call the wide board that runs just below the soffits on the vertical side of the house? This would be the board just above the clapboard on a wooden house. Also, what do you call the same board at the bottom on the clapboard between the clapboard and the foundation?
I use to know these terms, but I can’t remember them.
I do find your online information very useful. Thanks for having most of what I need in one place. - M.M. 8/14/2013
Definition of cornice molding or cornice trim: The horizontal board running at the top of a building exterior wall is a cornice molding or cornice trim board; some buildings have a decorative cornice while more common on simple residential structures is a plain horizontal trim board. The cornice is also described in some dictionaries as the uppermost part of an entablature. Cornice molding also is used indoors in some buildings and appears as a trim board mounted at the juncture of wall top and ceiling.
Definition of frieze board: a frieze board is a horizontal decorative board at the top of a wall or between the cornice and the wall covering; a frieze board may appear on the building exterior or on an interior wall as well. Some architects and builders may refer to the horizontal board at the top of the wall, below the soffit as simply the frieze board, omitting any discussion of (the more complex) cornice or cornice trim.
Other sources describe the frieze board as part of a classical entablature located between the architrave and the cornice. But I don't like this usage of architrave when discussing exterior building wall trim because properly an architrave is a decorated / decorative horizontal beam or lintel resting on the top of two or more columns in classical architecture, or found above a building window or door.
Definition of entablature: on a classical building the entablature is a combination of decorative elements that rests atop columns, made up typically of an architrave, frieze, and cornice. The term entablature is used then to describe a built-up combination of horizontal decorative components.
Definition of facia board or fascia trim: The horizontal board running along the outer edge of a soffit, typically covered or mostly covered by a gutter on modern homes, is the fascia board. Dont' confuse fascia board with cornice molding which is below the soffit and in the plane of the wall itself. On some buildings the water table trim is a bit more complex, using at least two pieces of horizontal trim: a narrow board, perhaps 1-3" in width is placed on an angle sloping away from the wall to form a drip cap atop a 6-10" wide horizontal trim board placed flat against the building.
Definition of water table trim board: The horizontal board running along the bottom of a building exterior wall siding such as common on clapboard-sided homes is often called a water table trim board.
A very helpful reference that provides illustrative sketches and definitions of building components and terms is Architectural Graphic Standards, by Ramsey Sleeper 
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
 Basic Housing Inspection, US DHEW, S 352.75 U48, p.144, out of print, but is available in most state libraries; New York State version, ca 1955, source of our page top sketch of house parts. However even this illustration appears to have been copied from a still earlier source and we have seen this identical drawing with different numbers and often published without a consistent key that defines the numbered items.
 Allen, Edward; Thallon, Rob (2011). Fundamentals of Residential Construction. John Wiley & Sons.
 Anderson, Leroy Oscar (2002) . Wood-frame house construction. New York: Books for Business. ISBN 0-89499-167-1.
 Architectural Graphic Standards: Student Edition (Ramsey/Sleeper Architectural Graphic Standards Series) [Paperback]
Charles George Ramsey (Author), Harold Reeve Sleeper (Author), Bruce Bassler (Editor), Wiley; 11 edition (March 3, 2008), ISBN-10: 0470085460 or ISBN-13: 978-0470085462
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.