Essential Log Home Key Terms

A complete glossary of terms relating to building your log home.

Written by Log Home Living Editors

Coventry_Burton21_Twilight_11868_2023-05-12_13-34

Log Provider/Designer: Coventry Log Homes; Photographer: Mark Sorenson

A -

Active solar heating: Use of a system that converts and stores energy from solar radiation to heat a home or its water.
Activity zones: Categorization of a home's spaces by what activities each space will accommodate. Used to help design a home's floorplan.
Adhesion: In comparing caulks, adhesion measures a caulk's ability to stick to another object, such as wood. The adhesion of some caulks may be reduced if a wood has been treated with a preservative.
Adhesive: High-performance glue used to adhere wood or other building components. May be used as a sealant in log homes.
Adjustable rate mortgage: Mortgage loan that has a flexible interest rate over the course of its term, as opposed to a fixed rate mortgage.
Adze: A hand tool that resembles an ax, but which has a flat, curved blade. Used to hew, or square, logs.
Air-Dried: Logs are considered air-dried when they have been dried in producers' yards or warehouses for six to 24 months.
Appraisal: An evaluation made by a lender to establish the value of a home before the lender approves a loan on that home.
Awning window: Type of window that opens out from the bottom.

B -

Backfill: Placement of excavated or imported soil or fill around the base of a home's foundation.
Bay window: A window or grouping of windows that protrudes outside of a home's exterior wall.
Beam: Horizontal member of a home's structural frame.
Blueprints: One name for the construction drawings used to build a home.
Borate: Chemical used as an insecticide to inhibit insect infestations in wood.
Brown rot: Along with white rot, one of two kinds of decay caused by fungi. Affected wood is browner than normal and tends to crack across the grain, shrink and collapse. Sometimes mistakenly called dry rot.
Bubble diagram: A preliminary design tool used to assign size and location to rooms within a developing floorplan.
Buck: Frame of dimensional lumber set into a log wall and used to frame windows and doors.
Builder-dealer: Sales representative for a log home producer who also serves as a professional builder or general contractor.
Builder's risk insurance: Insurance policy carried during construction that covers damage to home or property caused by fire, wind, theft or vandalism.
Building code: Standards of construction designed to protect the health and safety of a home's occupants.
Building permit: Permit issued by a municipality that allows construction work on a specific site to go forward according to approved plans. Ensures that all proposed construction work meets building code and is added to the tax rolls.
Building system: The master structural engineering plan that defines how components of a log home are connected to one another and how these components interact once connected. Ensures that every home produced under the system will be structurally sound.
Butt and pass corner: A form of butt corner where one log end extends beyond the intersection with the log in the opposing wall. In this design, every other log extends past the corner, giving a home that distinctive log home look.
Butt joint: Fastening together of two shorter logs end to end to create a longer timber that will span the length of a wall.

C -

Cambium: A thin-walled layer of cells beneath the inner bark of a tree, made of living cells that continually divide and account for the tree's growth. Bark cells are formed on the outside of the cambium, wood cells on the inside.
Cape Cod: A type of home design typified by one and a half stories and a simple gable roof.
Casement window: Style of window that typically opens out with a crank mechanism.
Caulk: The most common type of sealing material used on log homes, available in five different formulations: acrylic, butyl, oil-base, silicone and urethane.
Change order: Written record of a change made to a building project once construction is under way. Builders may charge for each change order a home owner requests.
Character log: Log that contains imperfections, such as scars or burls, that are considered aesthetically pleasing or interesting.
Check: Crack-like opening that forms in a log as it shrinks and dries.
Chinking: Historically a mortar-based material used to seal the gaps between logs, modern chinking resembles mortar, but remains soft and pliable to move with the logs. Chinking is often used as a visual accent to log walls.
Close grain: Wood with close grain has narrow, inconspicuous annual growth rings and/or closely spaced pores.
Closed-film coating: High-gloss wood coating, such as spar varnish or polyurethane, that forms a hard, brittle film on the wood's surface.
Coarse grain: Wood with coarse grain has wide, conspicuous annual growth rings.
Cohesion: In comparing caulks, cohesion is a measure of a caulk's ability to adhere to itself without pulling apart when it's stretched.
Colonial: A type of home design typified by two stories with a central hall and symmetrical window placement.
Comparable: The sales price of a similar home in a similar neighborhood, used to appraise the value of a home.
Compression/compression recovery: In comparing foam gasketing materials as log wall sealants, compression indicates how easy or difficult it is to compress the foam between log courses. Compression recovery indicates how completely the foam recovers to its original height after extended compression.
Conductivity: An inverse measure of the insulating value or resistance to heat flow of a material. The lower the conductivity, the higher the insulating value. Usually expressed as a number of Btu (British thermal units).
Construction draw: Amount of money paid out from a bank-financed construction loan in exchange for proof that labor and materials have been used to complete a certain stage of a building project. Draws usually follow a set draw schedule.
Construction to permanent loan: A single loan that includes both a construction loan e lement and a long-term mortgage. This type of loan may result in lower origination fees than would be required by two separate loans.
Corner post: In this corner style, the ends of the intersecting logs do not touch, but connect with, or butt into, a vertical corner post.
Corner-support system: A method of stacking logs in which the logs only touch at the corners where walls meet. Usually the 1-inch to 3-inch gap between the logs is filled with chinking to create a seal against air infiltration
Cost-plus: Type of contract made between a general contractor and a home owner that stipulates the owner will pay for the cost of building materials as the project progresses, plus an added percentage for the general contractor's fee. This type of contract is opposite of a fixed-price contract.
Cure rate: In comparing caulks, the time it takes for a caulk to form a "skin" that is non-sticky to the touch.
Cutting detail: The extent to which logs in a log package are cut to specific lengths before being shipped to a home construction site.

D -

D-shape: A style of logprofile in which one side of the log is left rounded, while the other is flattened. Allows for flat interior log walls that resemble paneling.
Dogtrot: A type of home design typified by two small log cabins or pens connected by an open breezeway.
Dormer: A structure that protrudes from a sloping roof and contains a window or group of windows.
Double-hung window: A window style with two separate sashes, each of which can be raised or lowered vertically in the window frame.
Dovetail corners: A style of interlocking corner created when the end of each log is cut into a fan-shaped wedge that is narrower toward the middle of the log. Most often used with square or rectangular logs.
Drawknife: A two-handled blade that is used to peel bark from logs.
Draw schedule: A schedule of payments that will be made to a general contractor or builder as work progresses on a building project.
Drift pins: Typically unthreaded steel rods 1 to 2 feet long. Designed to be driven through two or more courses of logs in pre-drilled holes about 1/16-inch less in diameter than the drift pin.
Drip edge: A lip or protrusion on the lower outside edge of logs that forces rainwater to drain down the exterior face of a log wall and past the seams between logs
Durability: In comparing caulks, durability is the ability of a caulk to retain adhesive, cohesive and recovery properties over the 20- to 40-year useful life of the product when subjected to repeated movement and exposure to wind, water, temperature changes and degradation by sunlight and ozone.

E -

Earlywood: In a tree's annual growth ring, the portion formed in the spring, which is light in color.
Easement: Right that one party owns to a portion of another party's property for a limited use. For instance, a utility company might own the right to cross a section of land owned by a private owner.
Elevation: A type of architectural drawing that depicts each facade of a home when viewed straight on.

F -

Fascia: The board that encloses the ends of a roof overhang.
Fasteners: Hardware used to fasten logs to one another and make a log wall more rigid.
Fixed glass window: Also called a picture window, a window that does not open.
Fixed price: A type of contract in which a builder or general contractor sets a price for a construction job up front. Opposite of a cost-plus contract.
Fixed rate: A mortgage loan in which the interest rate remains the same over the entire term of the mortgage.
Flashing: A sheet material, such as metal, that bridges two building elements and prevents water from entering.
Fluorescent: A type of lighting that is energy-efficient, somewhat "cool" in its color spectrum and glare-free.
Foam gasket or tape: Putty- or rope-like extrusions of PVC foam that are used to prevent drafts or moisture from seeping between logs.
Footing: The base of the foundation that supports the foundation walls.
Frass: Sawdust-like debris that is pushed out of holes in wood bored by insects.
Frieze: A horizontal band or board that appears at the top of a wall.
Full-length support system: A method of stacking logs into walls in which the logs intersect at the corners and then rest securely on one another along the entire length of the wall.
Full logs: Logs that are not sawn in half.
Fungi: Plants that cause decay as they feed on the substances found in wood.
Fungicide: Chemical agent that inhibits the growth of fungi on wood.

G -

Gable: The triangular shaped wall at the end of a roof.
Galley: A type of kitchen in which the appliances and cabinetry are lined up against a single wall.
Gambrel: A type of roof, often used on barns, that features two pitches on each side of the roof, the top section typically less steep than the bottom section.
General contractor: A professional who oversees a construction project, including the scheduling, supervision and payment of subcontractors.
Graduated payment mortgage: A mortgage with payments that increase over a five- or 10-year period. Designed primarily to help young, first-time buyers with rising income, the loans are more expensive than other type loans in the long run.
Grain: Wood's grain usually refers to the quality of a log's annual growth rings or to the arrangement of the wood fibers in a log. Annual rings are said to have either a fine or coarse grain.
Green wood: Wood or logs that are used within weeks or sometimes even days of having been cut.
Gunability: In comparing caulks, a caulk's ability to be applied using a caulking gun.

H -

Half logs: Logs that are sawn in half lengthwise and applied to a conventional stud-framed wall to create a wall that looks like full logs.
Halogen: Bright white light source that is highly energy efficient and compact.
Handcrafters: Log producers who do not use mechanization to produce logs of uniform shape or size. Handcrafters typically use some hand tools and craft each log home individually.
Hand-hewn: Log that has been squared through the use of hand tools such as an adze or ax.
Hardscape: In landscaping, refers to structures and features such as walls, pathways, pools and ponds.
Header: Built-up horizontal member of a home's frame that tops a window or doorway.
Heartwood: Found just inside the sapwood of a tree, heartwood consists of inactive wood cells that no longer conduct sap. Usually slightly darker in color and more resistant to decay than sapwood.
Horizontal surfaces: The load-bearing log surfaces that touch when logs are stacked horizontally to form a wall. These surfaces form the top and bottom of the log profile, or its shape as viewed from the end.
HVAC: Heating, ventilation and air-conditioning systems.

I -

Incandescent: Type of light supplied by a bulb with a glowing filament or wire. The light is "warm" in tone but not highly energy-efficient.
Inspection: Review of work on a construction job. May be performed by a local jurisdiction's building inspector to ensure that work is following approved plans and building codes, and by an inspector sent by a lending institution to ensure that work is completed before money is paid out to the general contractor.
Interlocking corner: A more complex type of log home corner in which wood is removed from the four sides of a log, leaving a recessed area that locks into a similar area on the intersecting log and holds both logs rigidly in place in all directions.

J -

Jalousie window: A type of window that features horizontal slats of glass that can be opened or closed.
Joist: A horizontal beam that supports the weight of a floor or ceiling.

K -

Kiln-dried: Logs that are force-dried in a kiln to less than 15 percent moisture content. The logs are subjected to heat and humidity in stages to both dry them and reduce the side effects of drying, such as checking, twisting and warping.
Knot: A portion of a branch or limb that is incorporated in a piece of lumber. Knots interrupt the direction and flow of the wood's fibers and can affect the wood's strength.

L -

Lag screw/bolt: Fastener used in log home construction.
Laminated logs: Built-up timbers that are manufactured by gluing, or laminating, dimensional lumber together, then shaping the timbers into traditional log profiles.
Lap siding: Wood siding material that has a flat exterior surface, characterized by boards that widen at their base.
Lateral load: Those loads imposed perpendicularly to a wall surface by winds and earthquakes.
Latewood: In a tree's annual growth ring, the darker portion, which is formed later in the growing season. Latewood is generally denser and stronger mechanically than earlywood.
Lien waiver: A legal document signed by subcontractors stating that they have been paid for work completed on a construction project and cannot make a claim against the home for lack of payment.
Lignin: A substance found in wood that both bonds the wood's cells together and gives the wood its elasticity.
Linear footage logs: Logs that are delivered to a home construction site without pre-cutting of the logs to any specific length.
Lintel: A horizontal member of a home's frame that forms the top of a window or door opening.
Loan to value ratio: A measurement of the size of the loan in comparison to the value of a home. Many lenders prefer a down payment of 20 percent of the home's value, to establish a loan-to-value ratio of 80 percent when a loan is made.
Log grading: Practice of ranking an individual log's suitability for use in a log home and its overall quality, using set standards.
Log profile: The shape of the log when viewed from its end. The top and bottom surfaces are the horizontal surfaces. The side, or vertical, surfaces are commonly referred to as the visible surfaces because they remain exposed when the logs are stacked into walls.
Log scribe: Tool used to mark the shape and outline of one log onto the log that will sit above it in a log wall.
Log siding: Siding material made up of logs that are sawn into thin strips, which still retain the curved shape of the log.

M -

Manufacturers: Log producers that use mechanized saws, planes and shapers to produce logs that are of uniform size and shape.
Material package: Building materials that are purchased along with the logs for a home.
Microporous film coating: Created by a wood preservative or finish with chemical agents that adhere to the edges of the wood's open pores, making them smaller. Prevents rain or dew water droplets from entering the wood's pores, but allows water vapor from inside the log to pass through to the outside.
Mildewcide: Chemical agent in a wood preservative or finish that inhibits the growth of mildew.
Mill glaze: A thin coating of sap, sugars or water that seep to the surface of a log once it's planed or sawn.
Moisture content: The amount of water present in a log, measured in terms of the weight of the water in respect to the weight of the log.
Mortise and tenon: A joint in which a protrusion (tenon) is inserted into a slot or hole (mortise).

O -

Old growth: A forest in which trees have grown in active competition for sunlight and moisture. Old-growth timber is usually straight and relatively free of knots.
Open-pore coatings: Solutions of oils or waxes in which color pigments and other ingredients are suspended. Designed to soak into the wood's fibers and repel water much the same as oil repels water. This type of wood finish or preservative does not form a film on the wood's surface.
OSB: Oriented strand board; an engineered wood product created by laminating shreds of wood into sheets.
Overlapping corners: A type of corner design in which logs overlap each other at the corners, and the ends of all logs continue past the corner.

P -

Partition wall: A wall that separates spaces in a home. In log homes, partition walls typically are built using conventional stud-frame construction, rather than logs.
Passive solar heating: A system that uses certain building materials (such as masonry) to collect and release energy from solar radiation.
Percolation (or "perc") test: Test performed to measure how porous soil is.
Pier: A type of support used as a foundation, which consists of vertical poles or columns set on footers.
Pith: The soft tissue about which the first wood growth in a tree takes place.
Plate: A horizontal member of the frame of a home on which the rafters rest.
Points: A percentage of the loan amount that lenders charge for making the loan, typically 1 to 5 percent, depending on the term of the loan and the interest rate offered.
Post: A vertical member of a supporting frame.
Post and beam: Type of construction characterized by exposed timbers that form a structural frame. The timbers may be joined by traditional carved wood joinery or by metal hardware.
Preconstruction: Those activities that must be completed before construction of a home can begin, such as site clearing and installation of temporary utilities.
Pre-cut: Extent to which the logs contained in a package are notched and cut to specific lengths at the log producer's manufacturing facility before being shipped to the construction site.
Preliminary sketches: First sets of drawings submitted to a home owner by a professional designer.
Pressure treating: A process in which wood is saturated with a preservative under pressure, allowing the preservative to be absorbed deep into the wood's fibers.
Purlin: A roof support beam that runs parallel to the ridge beam and the long sides of a home.

R -

R-value: A measure of resistance to the flow of heat. Higher R-values indicate a material's greater ability to insulate.
Racking: A reaction to lateral forces pushing horizontally on a wall, racking causes walls that are not rigidly fastened to become deformed.
Random-length logs: Logs that are delivered to a home construction site without pre-cutting of the logs to any specific length.
Recovery: In comparing caulks, recovery measures a caulk's elasticity, or its ability to return to its original shape after repeated stretching and compressing.

S -

Saddle-notch corner: Also called saddle cope, hole saw or round notch corners, this corner style is used with round logs. A semicircular notch is cut in the bottom of each log so that it fits over, or saddles the rounded top of the log it intersects. At the corner intersection of these walls, the log courses overlap rather than butt into one another.
Saltbox: Type of home style in which one side of the roof pitches steeply, while the other has a shallower pitch, allowing for a half-story or loft in the home's second floor.
Salvaged wood: Wood — typically large, old-growth timbers — that is reclaimed from old structures and reused in new construction.
Sap stain: A fungus that discolors the sapwood, usually during storage and air-drying. It can be brown, steel gray, black or blue, but blue stain is the dominant type. May cause a permanent blemish that cannot be removed from the surface.
Sapwood: The wood formed just inside a tree's cambium layer. May comprise the first one to three inches of radial thickness beneath the bark and contains mostly living cells that carry sap from the roots to the leaves.
Sealants: Material used to ensure a weathertight seal between the logs stacked in a wall.
Second growth: A second-growth forest is a newer, managed forest grown on land that was previously cleared. Most of the lumber used in log home construction comes from second-growth forests.
Section: Type of architectural drawing that shows a cross-section view of a particular element of a home, such as a wall.
Seismic load: A measure of seismic pressure that must be taken into account for a home to meet building codes. Homes built in earthquake-prone areas will be required to withstand greater seismic pressures.
Setbacks: Minimum distance required by local zoning ordinances between a property line and the edge of a building.
Settlement: Movement of walls that occurs over time and with the shrinkage of logs as they lose their moisture.
Shear: A lateral force that can affect horizontal log walls by causing the logs to slide along one another. A log wall that's properly fastened will be more rigid and will resist shear force more efficiently.
Shed roof: A roof style with a single, typically shallow, pitch.
Shrinkage: The decreasing in size of a log as it loses some of its moisture content over time.
Sill: A horizontal member of a home's frame that forms the base of a window or door.
Skip peel: A method of removing bark from a log that leaves dark patches of the cambium layer visible on the surface of the log.
Snow load: A measurement of the weight of the heaviest snow load likely to occur in a two-month period in a certain region. Most roof systems are designed to carry a dead load of 20 pounds per square foot. In localized areas of some snow-belt regions, snow loads of 150 pounds per square foot are not uncommon.
Soffit: Boards that cover the underside of a roof overhang.
Softscape: In landscaping, the softscape comprises trees, plants, ground cover and flowers.
Soft rot: A shallow decay that develops slowly and mainly affects thin boards. There is usually an abrupt transition between the wood affected by soft rot and sound wood. Causes structural damage to wood surfaces, leaving cracks and fissures both in and across the grain.
Specifications: Description, in writing, of the materials, fixtures, finishes and methods to be used in building a home.
Specific heat: A measurement of a material's capacity to store thermal energy.
Spiral grain: Irregular grain pattern formed in a tree that has bent or twisted to seek out sunlight. Spiral grain is undesirable in a log, as it may lead to twisting as the wood dries.
Spline: A 1- to 2-inch-high strip of fiberboard or plastic about 1/8-inch thick, inserted into the spline groove on a log to create a physical barrier to air and water infiltration between logs stacked in a wall.
Standing dead: Used to describe standing trees that have been killed by fire, insects or some other cause. Wood in these trees is generally not affected by whatever killed them.
Starter strip: Generally a 1-by-2-inch wood strip nailed to the subfloor, over which the first log is set, creating a seal between the log wall and the subfloor.
Structural insulated panels: Building panels made up of a layer of high-density foam sandwiched between two layers of sheet material such as plywood, tongue-and-groove paneling or oriented strand board (OSB). Also known as stress skin panels.
Subcontractor: Tradesperson who performs a specific task in a construction job, such as installing plumbing, laying carpet or painting, under the supervision of a home owner or general contractor.
Super-insulated walls: Log building system that calls for conventional stud-framed and insulated walls, which are then sided with half-logs on the exterior and some form of finish material on the interior.
System built: Home built using a package of manufactured components.
Swedish cope: Log building method in which a half-moon shaped groove is chiseled out of the length of a log, allowing it to straddle the rounded surface of the log beneath it in a wall.

T -

Tap fee: A fee charged for connecting a home to a public or municipal utility, such as a public water or sewer system.
Thermal mass: A property of wood that slows the transfer of heat through a log wall due to the high heat retention capacity of the wall mass.
Thermal resistance: The insulating value of a material. Usually expressed as an R-value, resistance varies among wood species and depends on the density and other qualities of the wood.
Through-bolts: Threaded metal fasteners, 1/2- to 3/4-inch thick and either 2, 4 or 8 feet long. A length of through bolt is often connected to anchor bolts embedded in the foundation. When the desired length is reached, a washer and nut are added and tightened to pull the wall together.
Timber frame: Type of traditional construction characterized by exposed timbers that form a structural frame. The timbers are joined by traditional carved wood joinery.
Toolability: In comparing caulks, the ability of a caulk to be worked easily with tools.
Tongue-and-groove: System of joining elements in which a protrusion, or tongue, on one element fits into a groove on the other.
Trim: Woodwork, often detailed, that finishes off certain elements in a home, such as windows, doors, stairs and cabinetry.
Truss: Triangular-shaped construction element that supports a home's ceiling or roof, and allows for an open space below, unimpeded by posts.
Turn-key: Construction service that allows home owners to purchase a completely finished home, one that does not require any further work by the home owners.

U -

UV blocker: Chemical agent added to wood preservative or finish to inhibit the sun's graying affect on wood.

V -

Vapor barrier: A waterproof material or film placed between a heated area of the home and an area that is not heated to prevent moisture from seeping between the two areas.
Vent-free: A hearth product, such as a free-standing stove or fireplace, that operates without an exterior venting system.
Vertical loads: Loads on a home that consist of the weight of the roof system, snow loads and upper floors.
Visible surfaces: The vertical surfaces of the log profile that remain visible, inside the house and out, when the logs are stacked horizontally into log walls.

W -

Wane: The bark that remains on an edge of a milled log created by the lack of wood on the edge or corner.
Water absorption: In comparing foam gasketing materials as a sealant between logs, water absorption should be low. Gaskets should repel water from rain or splashing, not absorb it.
Water repellant: Element of wood preservative that forms a barrier to prevent even slight amounts of moisture from reaching the wood.
White rot: Along with brown rot, a major category of decay caused by fungi. Results in the wood losing its color and appearing whiter than normal. Wood affected by white rot will not crack against the grain and will only shrink and collapse when it is severely degraded.
Wind load: Measure of the force of the wind as it affects the structural integrity of a house. Homes built in hurricane-prone areas are required by code to withstand higher winds.
Wood foundation: A type of foundation featuring walls built of pressure-treated studs and plywood that is impervious to rot, decay and insect and fungus attack. The interior of these walls is similar to a conventional stud wall, allowing the basement to be insulated and finished with drywall or paneling.
Wood preservative: Specialized finish formulated to protect wood from the deteriorating effects of wind, rain and sunlight, and attacks by fungus, mold, mildew and insects.
Wood rays: Radial lines that emanate from the pith at the center of a tree to the outer rings of sapwood. Wood rays help store and transfer food within the tree.
Work triangle: Pattern of traffic in a kitchen made up of the steps between the three major work areas: the sink, the refrigerator and the oven or cooktop.
Workers compensation: Guarantees compensation for any worker, contractor or layperson working on a home project who might be injured while working on site.

Z -

Zero-clearance: Self-contained fireplace unit that can be placed in close proximity to other combustible building materials.