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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 and Canada.
Our page top sketch was published in 1931 by the U.S. department of commernce (Phelan 1931), used later 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.
Because we have found the the page top sketch (US Commerce Department Phelan 1931 cited at REFERENCES) 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.
Phelan's 1931 drawing is shown here.
CONTACT us with suggested changes or additions to these terms and definitions.
See BASIC HOME INSPECTION DEFINITIONS OF TERMS, found below.
[Click any image to see a larger, detailed view.]
Note: for brevity this list of house parts, keyed to the illustration shown here, is condensed to keywords and phrases. For more complete, more-eloquent detail about each house part or system, click the links given by various house parts in this list.
1. Chimney - used to vent flue gases from fireplaces or heating equipment.
See CHIMNEY INSPECTION DIAGNOSIS REPAIR
2. Chimney flue top or chimney rain cap (if present), required for safe, proper draft and to avoid water damage to flues.
See CHIMNEY RAIN CAP / RAIN COVER INSPECTION
3. Chimney crown or chimney top seal, seals against leaks around the flue.
See CHIMNEY "CAP" CROWN / TOP SEAL INSPECTION for detailed photos of these components.
4. Chimney Flashing seals the roof penetration to avoid leaks into the structure.
See CHIMNEY FLASHING Mistakes & Leaks.
5. Masonry fireplace,
See FIREPLACES & HEARTHS
6. Fireplace ash pit door or opening is found in the floor of the fireplace, usually near the back (if present at all). This permits sweeping ashes from the fireplace into an ash pit for later cleanout; improper construction risks a house fire.
See CHIMNEY CLEANOUT CLEARANCE to COMBUSTIBLES
7. Fireplace ash pit cleanout door. Access to the ash pit at the base of chimneys serving fireplaces as well as heating appliances.
See CHIMNEY CLEANOUT DOOR
8. Fireplace mantel - horizontal trim attached to wall above fireplace opening.
See FIREPLACES & HEARTHS - home
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) provides exit venting for under-roof ventilation systems.
See ROOF VENTILATION SPECIFICATIONS - home
See RIDGE VENT, ATTIC INSPECTION
See ROOF VENT SOFFIT + RIDGE NEEDED - for an explanation of why both ridge outlet and soffit intake vents are needed.
11. Ridge board (usually present on rafter-framed roofs after 1930), eases roof framing by providing a nail plate for rafters that meet at the roof ridge.
In some construction such as cathedral ceilings the ridge board becomes a supporting ridge beam.
See STRUCTURAL RIDGE BEAM
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)
See ROOF FRAMING TIES & BEAMS for a description of roof framing components including collar ties, rafter ties, structural ridge beams, other roof framing components & problems.
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.
16. Roof shingles (asphalt shingles, clay tiles, slates, wood shingles, or shakes, similar materials) -
See ROOFING INSPECTION & REPAIR for a list of all types of roof coverings
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.
See DRIP EDGE FLASHING for ROOFS
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.
See this GREEK REVIVAL CORNICE [illustration].
Illustrated above: Eaves, soffit, fascia board, cornice molding, cornice, frieze, soffit return or box-end, and at the gable end of this historic home, the rake and barge board and again the soffit return.
[Click to enlarge any image]
Definition of Fascia 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.
Don't 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.
See SHEATHING, EXTERIOR PRODUCT INDEX
See PLYWOOD Roof, Wall, Floor Decks & Sheathing
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
and FLOOR TYPES & DEFECTS
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;
36. Exterior siding (shown: clapboards)
See SIDING TYPES, INSTALLATION, DEFECTS
37. Interior partition wall or center wall partition (may be load bearing, supporting 2nd floor joists)
38. Interior wall covering: Plaster wall scratch coat or masonry for chimney (if present)
See PLASTER TYPE IDENTIFICATION
and DRYWALL HAZARDS, CHINESE
and DRYWALL INSTALLATION Best Practices
and DRYWALL MOLD RESISTANT
39. Grade level (top of soil around building).
See GRADING, DRAINAGE & SITE WORK
40. Foundation wall, along with wall footings (42) supports the structure and holds back earth where a basement or crawl space is included.
See FOUNDATION CRACKS & DAMAGE GUIDE
41. Sill sealer (insulation placed between sill plate and foundation wall top)
See AIR LEAK MINIMIZATION
42. Footing, supports the foundation wall.
See FOUNDATION DEFECTS OF OMISSION - MISSING
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)
See CONCRETE SLAB CRACK EVALUATION -
45. Compacted fill (or gravel atop fill or poly on gravel on fill) below basement floor slab
See BLOCK FOUNDATION BACKFILL DAMAGE
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.
See FRAMING DAMAGE, INSPECTION, REPAIR
47. Backfill around foundation wall.
See GRADING, DRAINAGE & SITE WORK
48. Rim joist or pier cap forms the perimeter framing of the building floor and rests atop the foundation wall. The rim joist, set on edge, is nailed to the sill plate. The rim joist and sill plate rest on pier top where a continuous foundation wall is not present.
See DECK JOIST INSTALLATION for a simple illustration that includes a rim joist design.
See STRUCTURAL DAMAGE PROBING
49. Pier, alternative to a continuous foundation wall, piers may support posts that in turn support perimeter girders or beams carrying the building wall loads.
51. Window jamb or window frame
52. Window sash frame
53. Window header
See WINDOW FLASHING & SEALING GUIDE
54. Window interior trim
55. Entry porch gable
57. Stair tread.
See STAIRS, RAILINGS, LANDINGS, RAMPS
58. Stair riser - the vertical distance between the walking surface of steps or treads, formed by a solid enclosure such as a board except where open risers are permitted.
See STAIR RISER SPECIFICATIONS
59. Stair stringer (structural support for stair treads and risers)
See STAIR STRINGER SPECIFICATIONS
60. Newell post at stair bottom (handrail ends at this post)
See GUARDRAILS on STAIRS
61. Stair rail or handrail; on landings or balconies: guardrail.
See STAIRS, RAILINGS, LANDINGS, RAMPS
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.
See GUARDRAIL CONSTRUCTION, STAIRS
Home inspections performed to ASHI or other professional home inspectors association, state or provincial licensing standards for home 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 or explanation.
Home 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 (American Society of Home Inspectors), the first national professional associations of home inspectors, has building experts examining residential structures in every U.S. State and CAHI (Canadian Association of Home Inspectors) has inspectors in every Canadian Province, these professional home inspectors present an opportunity to contribute to and share data and field experience with other construction-related professional groups and with trade associations.
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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 fascia 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. Don't 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 
At Field Guides to North American House Architecture we list (and you can buy at Amazon) books we have found particularly helpful in identifying architectural styles,
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