Glossary of Terms


Air-dried lumber.
Lumber that has been piled in yards or sheds for any length of time. For the United States as a whole, the minimum moisture content of thoroughly air-dried lumber is 12 to 15 percent and the average is somewhat higher. In the South, air-dried lumber may be no lower than 19 percent.

A space between roof insulation and roof boards for movement of air.

Anchor bolts.
Bolts to secure a wooden sill plate to concrete or masonry floor or wall.

The flat member of the inside trim of a window placed against the wall immediately beneath the stool.

A molding attached to one of a pair of swinging doors, against which the other door strikes.

Attic ventilators.
In houses, screened openings provided to ventilate an attic space. They are located in the soffit area as inlet ventilators and in the gable end or along the ridge as outlet ventilators. They can also consist of power-driven fans used as an exhaust system.
(See also Louver.)


Usually small vertical members in a railing used between a top rail and the stair treads or a bottom rail.

A railing made up of balusters, top rail, and sometimes bottom rail, used on the edge of stairs, balconies and porches.

Barge board.
A decorative board covering the projecting rafter (fly rafter) of the gable end. At the cornice, this member is a fascia board.

Base or baseboard.
A board placed against the wall around a room next to the floor to finish properly between floor and drywall.

Base shoe.
Molding used next to the floor on interior baseboard.

Batter board.
One of a pair of horizontal boards nailed to posts set at the corners of an excavation, used to indicated the desired level, also as a fastening for stretched strings to indicate outlines of foundation walls.

Bay window.
Any window spacing projecting outward from the walls of a building, either square or polygonal in plan.

A structural member transversely supporting a board.

Bearing partition.
A partition that supports any vertical load in addition to its own weight.

Bearing wall.
A wall that supports any vertical load in addition to its own weight.

Nailing in such a way that the nailheads are not visible on the face of the work–usually at the tongue of matched boards.

Boiled linseed oil.
Linseed oil in which enough lead, manganese, or cobalt salts have been incorporated to make the oil harden more rapidly when spread in thin coatings.

An inclined piece of framing lumber applied to wall or floor to stiffen the structure. Often used on walls as temporary bracing until framing has been completed.

Brick veneer.
Facing of brick laid against and fastened to sheathing of a frame wall or tile wall construction.

Small wood or metal members that are inserted in a diagonal position between the floor joists at midspan to act both as tension and compression members for the purpose of bracing the joists and spreading the action loads.

Built-up roof.
Roofing composed of three to five layers of asphalt felt laminated with coal, tar, pitch or asphalt. The top is finished with crusted slag or gravel. Generally used on flat or low pitched roofs.

Butt joint.
The junction where the end of two timbers or other members meet in a square-cut joint.


The upper member of a column, pilaster, door cornice, molding and the like.

Molding of various widths and thickness used to trim door and window openings at the jambs.

Collar beam.
Normal one-or-two-inch-thick members connecting opposite roof rafters. They serve to stiffen the roof structure.

In architecture: A perpendicular supporting member, circular or rectangular in section, usually consisting of a base, shaft and capital. In engineering: A vertical structural compression member that supports loads acting in the direction of its longitudinal axis.

In a building: Beads or drops of water (and frequently frost in extremely cold weather) that accumulate on the inside of the exterior covering of a building when warm, moisture-laden air from the interior reaches a point where the temperature no longer permits the air to sustain the moisture it holds. Use of louvers or attic ventilators will reduce moisture condensation in attics. A vapor barrier under the gypsum lath or dry wall on exposed walls will reduce condensation in them.

Conduit, electrical.
A pipe, usually metal, in which wire is installed.

Construction, frame.
A type of construction in which the structural parts are wood or depend upon wood frame for support. In codes, if masonry veneer is applied to the exterior walls, the classification of this type of construction is usually unchanged.

Coped joint.
See Scribing.

Corner bead.
A strip of formed sheet metal, sometimes combined with a strip of metal lath, placed on corners to reinforce them. Also, a strip of wood finish three-quarters-round or angular placed over a drywall corner for protection.

Corner boards.
Used as trim for the external corners of a house or other frame structure against which the ends of the siding are finished.

Corner braces.
Diagonal braces at the corners of frame structures to stiffen and strengthen the wall.

Overhang of a pitched roof at the eave line, usually consisting of facia board, a soffit for a closed cornice, and appropriate moldings.

Cornice return.
That portion of the cornice that returns on the gable-end of the house.

A flashing usually used on chimneys at the roofline to cover shingle flashing and to prevent moisture entry.

Cove molding.
A molding with a concave face used as trim or to finish interior corners.

Crawl space.
A shallow space below the living quarters of a basementless house, normally enclosed by the foundation wall.

A small drainage-diverting roof structure of single or double slope placed at the junction of larger surfaces that meet at an angle, such as above a chimney.

Diagonal bracing between adjacent floor joists, placed near the center of the joist span to prevent joists from twisting.


A rectangular groove across the width of a board or plank. In interior decoration, a special type of wall treatment.

Disintegration of wood or other substance through the action of fungi.

Deck paint.
Enamel with a high degree of resistance to mechanical wear, designed for use on such surfaces as porch floors.

The mass substance in a unit volume. When expressed in the metric system, it is numerically equal to the specific gravity of the same substance.

Temperature at which a vapor begins to deposit as a liquid. Applies especially to water in the atmosphere.

See Lumber dimension.

Direct nailing.
To nail perpendicular to the initial surface or to the junction of the pieces joined. Also termed face nailing.

Doorjamb, interior.
The surrounding case into which and out of which a door closes and opens. It consists of two upright pieces, called side jambs, and a horizontal head jamb.

An opening in a sloping roof, the framing of which projects out to form a vertical wall suitable for windows or other openings.

A pipe, usually of metal, for carrying rainwater from roof gutters.

a) A member of a cornice or other horizontal exterior finish course that has a projection beyond the other parts for throwing off water. b) A groove in the underside of a sill or drip cap to cause water to drop off on the outer edge instead of drawing back and running down the face of the building.

Drip cap.
A molding placed on the exterior topside of a door or window frame to cause water to drip beyond the outside of the frame.

Dry wall.
Interior covering materials such as gypsum board or plywood, which is applied in large sheets or panels.

In a house, usually round or rectangular metal pipes for distributing warm air from the heating plant to rooms or air from a conditioning device or as cold air returns. Ducts are also made of composition materials.


The margin or lower part of a roof projecting over the wall.

Expansion joint.
A bituminous fiber strip used to separate blocks or units of concrete to prevent cracking due to expansion as a result of temperature changes. Also used on concrete slabs.


Facia or fascia.
A flat board, band or face used sometimes by itself but usually in combination with moldings, often located at the outer face of the cornice.

Filler (wood).
A heavily pigmented preparation used for filling and leveling off the pores in open-pored woods.

In the absence of a specific ruling by the authority having jurisdiction, applies to materials for construction not combustible in the temperatures of ordinary fires and that will withstand such fires without serious impairment of their usefulness for at least one hour.

Fire-retardant chemical.
A chemical or preparation of chemicals used to reduce flammability or to retard spread of flame.

Fire stop.
A solid, tight closure of a concealed space, placed to prevent the spread of fire and smoke through such a space. In a frame wall, this will usually consist of two-by-four cross blocking between studs.

Sheet metal or other material used in roof and wall construction to protect a building from water seepage.

Flat paint.
An interior paint that combines a high proportion of pigment and dries to a flat or lusterless finish.

The space or passage in a chimney through which smoke, gas or fumes ascend. Each passage is called a flue, which together with any others and the surrounding masonry make up the chimney.

Flue lining.
Fire clay or terra-cotta pipe, round or square, usually made in all ordinary flue sizes and in two-foot lengths, used for the inner lining of chimneys with the brick or masonry work around the outside. Flue lining in chimneys runs from about a foot below the flue connection to the top of the chimney.

Fly rafters.
End rafters of the gable overhang supported by roof sheathing and lookouts.

A masonry section, usually concrete, in a rectangular form wider than the bottom of the foundation wall or pier it supports.

The supporting portion of a structure below the first-floor construction, or below grade, including the footings.

Framing, balloon.
A system of framing a building in which all vertical structural elements of the bearing walls and partitions consist of single pieces extending from the top of the foundation sill plate to the roofplate and to which all floor joists are fastened.

Framing, platform.
A system of framing a building in which floor joists of each story rest on the top plates of the story below or on the foundations sill for the first story, and the bearing walls and partitions rest on the subfloor of each story.

In house construction, a horizontal member connects the top of the siding with the soffit of the cornice.

The depth of frost penetration in soil. This depth varies in different parts of the country. Footings should be placed below this depth to prevent movement.

Fungi, wood.
Microscopic plants that live in damp wood and cause mold, stain and decay.

A chemical that is poisonous to fungi.

Strips of wood or metal applied to a wall or other surface to even it and normally serve as a fastening base for finish material.


In house construction, the portion of the roof above the eave line of a double-sloped roof.

Gable end.
An end wall having a gable.

Gloss enamel.
A finishing material made of varnish and sufficient pigments to provide opacity. Such enamel forms a hard coating with maximum smoothness of surface and a high degree of gloss.

Gloss (paint or enamel).
A paint or enamel that contains a relatively low proportion of pigment and dries to a sheen or luster.

A large principal beam of wood or steel used to support concentrated loads at isolated points along its length.

The direction, size, arrangement, appearance, or quality of the fibers in the wood.

Grain, edge (vertical).
Edge-grain lumber has been sawed parallel to the pith of the log and approximately at right angles of the growth rings, i.e., the rings form an angle of 45 degrees or more with the surface of the piece.

Grain, flat.
Flat-grain lumber has been sawed parallel to the pith of the log and approximately tangent to the growth rings, i.e.; the rings form an angle of less than 45 degrees with the surface of the piece.

Grain, quartersawn.
Another term for edge grain.

Mortar made of such consistency (by adding water) that it will just flow into the joints and cavities of the masonry work and fill them solid.

A flat wood, plywood or similar type member used to provide a connection at intersection of wood members. Most commonly used at joints of wood trusses. They are fastened by nails, screws, bolts or adhesives.

Gutter or eave trough.
A shallow channel or conduit of metal or wood set below and along the eaves of a house to catch and carry off rainwater from the roof.


a) A beam placed perpendicular to joists and to which joists are nailed in framing for chimney, stairway, or other opening. b) A wood lintel.

The inner or out floor of a fireplace, usually made of brick, tile or stone.

The wood extending from the pith to the sapwood, the cells of which no longer participate in the life process of the tree.

The external angle formed by the meeting of two sloping sides of a building.

Hip roof.
A roof that rises by inclined planes from all four sides of a building.

A device designed to increase the humidity within a room or a house by means of the discharge of water vapor. They may consist of individual room-size units or large units attached to the heating plant to condition the entire house.


A steel beam with a cross section resembling the letter I. It is used for long spans as basement beams or over wide wall openings, such as a double garage door, when wall and roof loads are imposed on the opening.

Insulation board, rigid.
A structural building board made of coarse wood or cane fiber in one-half and 25/32-inch thickness. It can be obtained in various size sheets, in various densities and with several treatments.

Insulation, thermal.
Any material high in resistance to heat transmission that, when placed in the walls, ceiling, or floors of a structure, will reduce the rate of heat flow.

Interior finish.
Material used to cover the interior framed areas, or materials of walls and ceilings.


Jack rafter.
A rafter that spans the distance from the wallplate to a hip, or from a valley to a ridge.

The side and head lining of a doorway, window or other opening.

The space between the adjacent surface of two members or components joined and held together by nails, flue, cement, mortar or other means.

Joint cement.
A powder that is usually mixed with water and used for joint treatment in gypsum-wallboard finish. Often called “spackle.”

One of a series of parallel beams, usually two inches in thickness, used to support floor and ceiling loads and supported in turn by larger beams, girders or bearing walls.


Kiln-dried lumber.
Lumber that has been kiln dried often to a moisture content of six to 12 percent. Common varieties of softwood lumber, such as framing lumber are dried to a somewhat higher moisture content.

In lumber, the portion of a branch or limb of a tree that appears on the edge or face of the piece.


A platform between flights of stairs or the termination of a flight of stairs.

A building material of wood, metal, gypsum or insulating board that is fastened to the frame of a building to act as a plaster base.

A framework of crossed wood or metal strips.

Ledger strip.
A strip of lumber nailed along the bottom of the side of a girder on which joists rests.

Space in a window sash for a single pane of glass. Also, a pane of glass.

A horizontal structure member that supports the load over an opening such as a door or window.

A short wood bracket or cantilever to support an overhang portion of a roof or the like, usually concealed from view.

An opening with a series of horizontal slats or arranged as to permit ventilation but to exclude rain, sunlight or vision. See also Attic ventilators.

Lumber is the product of the sawmill and planing mill not further manufactured other than by sawing, re-sawing and passing lengthwise through a standard planning machine, crosscutting to length and matching.

Lumber, boards.
Yard lumber from two inches to, but including, five inches thick and two or more inches wide. Includes joists, rafters, studs, plank and small timbers.

Lumber, dimension.
Yard lumber that is dressed and shaped on one edge in a grooved pattern and on the other in a tongued pattern.

Lumber, dressed size.
The dimension of lumber after shrinking from green dimension and after machining to size or pattern.

Lumber, matched.
Lumber that is dressed and shaped on one edge in a grooved pattern and on the other in a tongued pattern.

Lumber, shiplap.
Lumber that is edged-dressed to make a close rabbeted or lapped joints.

Lumber, timbers.
Yard lumbers five or more inches in least dimension. Includes beams, stringers, posts, caps, sills, girders and purlins.

Lumber, yard.
Lumber of those grades, sizes and patterns that are generally intended for ordinary construction such as framework and rough coverage of houses.


The shelf above a fireplace. Also used in referring to the decorative trim around a fireplace opening.

Stone, brick, concrete, hollow-tile, concrete block, gypsum-block, or other similar building units or materials or a combination of the same, bonded together with mortar to form a wall, pier, buttress or similar mass.

Metal lath.
Sheets of metal that are slit and drawn out to form openings. Used as a plaster base for walls and ceilings and as reinforcing over other forms of plaster base.

Generally all building materials made of finished wood and manufactured in millwork plants and planning mills are included under the term “millwork.” It includes such items as inside and outside doors, window and doorframes, blinds, porch work, mantels, panel work, stairways, moldings, and interior trim. It normally does not include flooring, ceiling or siding.

Miter joint.
The joint of two pieces at an angle that bisects the joining angle. For example, the miter joint at the side and head casing at a door opening is made at a 45-degree angle.

Moisture content of wood.
Weight of the water contained in the wood, usually expressed as a percentage of the weight of the ovendry wood.

A wood strip having curved or projecting surface used for decorative purposes.

A slot cut into a board, plank or timber, usually edgewise, to receive tenon of another board, plank or timer to form a joint.

A vertical bar or divider in the frame between windows, doors or other openings.

A small member which divides the glass or openings of sash or doors.


Natural finish.
A transparent finish which does not seriously alter the original color or grain of the natural wood. Natural finishes are usually provided by sealers, oils, varnishes, water-repellant preservatives and other similar materials.

A post to which the end of a stair railing or balustrade is fastened. Also, any post to which a railing or balustrade is fastened.

Nonbearing wall.
A wall supporting no load other than its own weight.

The projecting edge of a molding or drip. Usually applied to the projecting molding on the edge of a stair tread.

A crosswise rabbet at the end of a board.


O.C., on center.
The measurement of spacing for studs, rafters, joists and the like in a building from the center of one member to the center of the next.

An extension of a rafter beyond the wall line. Usually a smaller member nailed to a larger rafter to form a cornice or roof overhang.


A combination of pigments with suitable thinners or oils to provide decorative and protective coatings.

In house construction, a thin flat piece of wood, plywood or similar material, framed by stiles and rails as in a door or fitted into grooves of thicker material with molded edges for decorative wall treatment.

Paper, building.
A general term used for papers, felts and similar sheet materials used in buildings without reference to the properties or uses.

Paper, sheathing.
A building material, generally paper or felt, used in wall and roof construction as a protection against the passage of air and sometimes moisture.

A wall that subdivides spaces within any story of a building.

As applied to nails, it originally indicated the price per hundred. The term now serves as a measure of nail length and is abbreviated by the letter ‘d’.

A measure of water vapor movement through a material (grains per square foot per hour per inch of mercury difference in vapor pressure).

A column of masonry, usually rectangular in horizontal cross section, used to support other structural members.

A powdered solid in suitable degree of subdivision for use in paint or enamel.

The incline of a roof or the ratio of the total rise to the total width of a house, i.e., an eight-foot rise and 24-foot width is one-third pitch roof. Roof slope is expressed in the inch rise per foot of run.

Still plate: a horizontal member anchored to a masonry wall. Sole plate: bottom horizontal member of a frame wall. Top plate: top horizontal member of a frame wall supporting ceiling joists, rafters or other members.

To cut a lengthwise groove in a board or plank.

Exactly perpendicular; vertical.

A term used to denote the number of thickness’ or layers or roofing felt, veneer in plywood, or layers in built-up materials, in any finished piece of such material.

A piece of wood made of three or more layers of veneer joined with glue and usually laid with the grain of adjoining plies at right angles. Almost always an odd number of plies are used to provide balanced construction.

Wood cells of comparatively large diameter that have open ends and are set one above the other to form continuous tubes. The openings of the vessels on the surface of a piece of wood are referred to as pores.

Any substance that, for a reasonable length of time will prevent the action of wood-destroying fungi, bores of various kinds and similar destructive agents when the wood has been properly coated or impregnated with it.

The first coat of paint in a paint job that consists of two or more coats; also the paint used for such a first coat.

A type of cement usually made of whiting and boiled linseed oil, beaten or kneaded to the consistency of dough and used in sealing glass in sash, filling small holes and crevices in wood and for similar purposes.


Quarter round.
A small molding that has the cross section of a quarter circle.


A rectangular longitudinal groove cut in the corner edge of a board or plank.

One of a series of structural members of a roof designed to support roof loads. The rafters of a flat roof are sometimes called roof joists.

Rafter, hip.
A rafter that forms the intersection of an external roof angle.

Rafter, valley.
A rafter that forms the intersection of an internal roof angle. The valley rafter is normally made of double-two-inch-thick members.

Cross members of panel doors of a sash. Also the upper and lower members of a balustrades or staircase, extending from one vertical support, such as a post, to another.

Trim members that run to the roof slope and form the finish between the wall and a gable roof extension.

Raw linseed oil.
The crude product processed from flaxseed and usually without much subsequent treatment.

Reflective insulation.
Sheet material with one or both surfaces of comparatively low heat emissivity, such as aluminum foil. When used in building construction the surfaces face air spaces, reducing the radiation across the air space.

Steel rods or metal fabric placed in concrete slabs, beams, or columns to increase their strength.

Relative humidity.
The amount of water vapor in the atmosphere, expressed as a percentage of the maximum quantity that could be present at a given temperature. (The actual amount of water vapor that can be held in space increases with the temperature.

The horizontal line at the junction of the top edges of two sloping roof surfaces.

Ridge board.
The board placed on the edge at the ridge of the roof into which the upper ends of the rafters are fastened.

Each of the vertical boards closing the spaces between the treads of stairways.

Roll roofing.
Roofing material, composed of fiber and saturated with asphalt, that is supplied in 36-inch wide rolls with 108 square feet of material. Weights are generally 45 to 90 pounds per roll.

Roof sheathing.
The boards or sheet material fastened to the roof rafters on which the shingle or other roof covering is laid.

In stairs, the net width of a step or the horizontal distance covered by a flight of stairs.


Two sloping surfaces meeting in a horizontal ridge, used between the backside of a chimney, or other vertical surface, and a sloping roof.

The outer zone of wood, next to the bark. In the living tree it contains some living cells (the heartwood contains none), as well as dead and dying cells. In most species, it is lighter colored than the heartwood. In all species, it is lacking in decay resistance.

A single light frame containing one or more lights of glass.

Fitting woodwork to an irregular surface. In moldings, cutting the end of one piece to fit the molded face of the other at an interior angle to replace a miter joint.

A finishing material, either clear or pigmented, that is usually applied directly over uncoated wood for the purpose of sealing the surface.

Removing moisture from green wood in order to improve its serviceability.

Semi-gloss paint or enamel.
A paint or enamel made with a slight insufficiency of nonvolatile vehicle so that its coating, when dry, has some luster but is not very glossy.

A thick, handsplit shingle, resawed to form two shakes; usually edge-grained.

The structural covering, usually wood boards or plywood, used over studs or rafters of a structure. Structural building board is normally used only as wall sheathing.

Sheathing paper.
See Paper, sheathing.

Sheet metal work.
All components of a house employing sheet metal, such as flashing, gutters and downspouts.

A transparent coating made by dissolving lac, a resin of secretion of the lac bug (a scale insect that thrives in tropical countries, especially India), in alcohol.

Roof covering of asphalt, asbestos, wood, tile, slate or other thick material cut to stock lengths, widths and thickness’.

Shingles, siding.
Various kinds of shingles, such as wood shingles or shakes and non-wood shingles, that are used over sheathing for exterior sidewall covering of a structure.

See Lumber, shiplap.

Usually lightweight louvered or flush wood or non-wood frames in the form of doors located at each side of a window. Some are made to close over the window for protection; others are fastened to the wall as a decorative device.

The finish covering of the outside wall of a frame building, whether made of horizontal weatherboards, vertical boards with battens, shingles or other materials.

Siding, bevel (lap siding).
Wedge-shaped boards used as horizontal siding in a lapped pattern. This siding varies in butt thickness from one-half to three-fourth inch and in widths up to 12 inches. Normally used over some type of sheathing.

Siding, drop.
Usually three-quarters inch thick and six and eight inches wide with tongued-and-grooved or shiplap edges. Often used as siding without sheathing in secondary buildings.

The lowest member of the frame of a structure, resting on the foundation and supporting the floor joists or the uprights of the wall. The member forming the lower side of an opening, as a doorsill, windowsill, etc.

Usually, a wood member embedded in concrete, as in a floor, that serves to support and to fasten subfloor or flooring.

Usually the underside of an overhanging cornice.

Soil cover (ground cover).
A light covering of plastic film, roll roofing, or similar materials used over the soil in crawl spaces of buildings to minimize moisture permeation of the area.

Soil stack.
A general term for the vertical main of a system of soil, waste or ventpiping.

Sole or sole plate.
See Plate.

Solid bridging.
A solid member placed between adjacent floor joists near the center of the span to prevent joists from twisting.

The distance between structural supports such as walls, columns, piers, beams, girders and trusses.

Splash block.
A small masonry block laid with the top close to the ground surface to receive roof drainage from downspouts and to carry it away from the building.

A unit of measure–100 square feet–usually applied to roofing material. Sidewall coverings are sometimes packed to cover 100 square feet and are sold on that basis.

Stain, shingle.
A form of oil plant, very thin in consistency, intended for coloring wood with rough surfaces, such as shingles, without forming a coating of significant thickness or gloss.

Stair landing.
See Landing.

Stair rise.
See Rise.

An upright framing member in a panel door.

A flat molding fitted over the windowsill between jambs and contacting the bottom rail of the lower sash.

Storm sash or storm window.
An extra window usually placed on the outside of an existing one as additional protection against cold weather.

That part of a building between any floor and the floor or roof next above.

Strip flooring.
Wood flooring consisting of narrow, matched strips.

String, stringer.
A timber or other support for cross members in floors or ceilings. In stairs, the support on which the stair tread rests; also stringboard.

Most commonly refers to an outside plaster made with Portland cement as its base.

One of a series of slender wood or metal vertical structural member placed as supporting elements in walls and partitions. (Plural: studs or studding.)

Boards or plywood laid on joists over which a finish floor is to be laid.

Suspended ceiling.
A ceiling system supported by hanging it from the overhead structural framing.


A strip of wood or metal with beveled edges used over the finish floor and the sill of exterior doors.

To drive a nail at a slant with the initial surface in order to permit it to penetrate into a second member.

Tongued and grooved.
See Dressed and matched.
The horizontal board in a stairway on which the foot is placed.

The finish materials in a building, such as moldings, applied around openings (window trim, door trim) or at the floor and ceiling of rooms (baseboard, cornice and other moldings).

A beam or joist to which a header is nailed in framing for a chimney, stairway or other opening.

A frame or jointed structure designed to act as a beam of long span, while each member is usually subjected to longitudinal stress only, either tension or compression.

A volatile oil used as a thinner in paints and as a solvent in varnishes. Chemically, it is a mixture of terpenes.


A coating applied prior to the finish or topcoats of a paint job. It may be the first of two or the second of three coats. In some usage of the word, it may become synonymous with priming coat.

Under layment.
A material placed under the finish coverings, such as flooring, or shingles, to provide a smooth even surface for applying the finish.


The internal angle formed by the junction of two sloping sides of a roof.

Vapor barrier.
Material used to retard the movement of water vapor into walls and prevent condensation in them. Usually considered as having a perm value of less than 1.0. Applied separately over the warm side of exposed walls or as a part of batt or blanket insulation.

A thickened preparation of drying oil or drying oil and resin suitable for spreading on surfaces to form continuous, transparent coatings, or for mixing with pigments to make enamels.

The liquid portion of a finishing material; it consists of the binder (nonvolatile) and volatile thinners.

Thin sheets of wood made by rotary cutting or slicing of a log.

A pipe or duct which allows flow of air as an inlet or outlet.


Water repellant preservative.
A liquid designed to penetrate into wood and impart water repellency and a moderate preservative protection. It is used for millwork, such as sash and frames and is usually applied by dipping.

Narrow or jamb-width sections of thin metal or other material to prevent infiltration of air and moisture around windows and doors. Compression weather-stripped prevents air infiltration, provides tension, and acts as a counter balance.