Halswell Timber

GLOSSARY OF TIMBER TERMS

Abbreviations and meanings of the timber terms used for finishing, treatment, grading, building and more.

Term Meaning Abb.
Finishes    
Rough Sawn As it comes straight of the saw R/S
Band Sawn Vertical sawcut B/S
Dressed Four Sides Dressed smooth suitable for joinery D4S
Plainer Gauged Machined at high speed to a standard uniform size for the building market P/G
Tongue & Groove   T&G
Tongue & Groove V-Joint   T&G V-J
End-Matched   E/M
Pre-primed Undercoat sealer (oil or water based) P/P
Treatment    
Untreated Untreated U/T
H1.2 Boron Treated for protection against borer H1.2
H3.2 Exterior Treated for exposure to weather but not in ground contact H3.2
H4 Ground Treated for ground contact H4
H5 Treated for ground contact ground near fresh water or in soggy ground H5
H6 Treated ground for near salt water immersion H6
Grades    
Dressing A Knot and defect free D.A.
Dressing B Select Small tight knots on all 4 faces. Will be able to cut some clear out of board. D.B. Select
Dressing B Tight knots with no restriction on the amount per board D.B.
Clears Knot and defect free CL
Clears 2 Clean on 2 edges, 1 face, and small tight knots on 1 face CL2
Dressing Grade Tight knots that can be cracked with no restriction on the amount per board. Hairline cracks in board are possible. D/G
No.1 Framing Knot size no bigger than 1/3 cross section of the board No.1
Boxing Has spike knots, butterfly knots, loose knots and edge knots BOX
Ordinary Building Pinhole borer, cracked knots, hairline cracks in board, large knots O.B.
Double Defect Open defects on back and face of plywood DD
Finger-Jointed   F/J
Durability    
Non Durable 0-2 years  
Moderately Durable 2-5 years  
Durable 5-10 years  
Very Durable 10+ years  
Defects    
Pinhole A hole usually not exceeding 2mm diameter. The insects who create these holes feed off the starch in the sap of the living tress and when the tree is felled, sap dries up and they die.  
Gum Vein A ribbon of gum produced in trees as a repsonse to fire damage  
Shake Splits in the structure of the wood caused by growth defects or shrinkage stress  
Check A small crack running through the grain of a timber surface usually caused by being dried too quickly  
Dry    
Moisture Content The amount of moisture in timber (measured in a percentage) MC
Kiln Dried Has been dried in a kiln to approx 12-15% MC K/D
Air Dried Has been dried by the natural air (usually undercover and strip-stacked) to anywhere between 15-25% MC A/D
Green Wet (MC ranging from 26-100%)  
Measurements    
Lineal Metre Running metre in .300 multiples LM
Square Metre / Area Length x Width M2
Cube Length x Width x Depth M3
Building    
Purlin Sits on top of trusses  
Truss A triangular arrangement of structural members that reduces non-axial forces on the truss to a set of axial forces in the members.  
Stud One of a small series of small closely spaced wall framing members.  
Dwang Block in between studs  
Joist One of a group of light, closely spaced beams used to support a floor deck or flat roof.  
Bearer Heavy section timber which supports joists  
Batten A long thin piece of rectangular shaped material supporting roof tiles or covering joints between panelings.  
Beam A straight structural member that acts primarily to resist non axial loads.  
Post Upright supporting a structure  
Pile A long slender piece of material driven into the ground to as a foundation.  
Plinth Triangular shaped timber for corner  
Lintel A beam that carries the load of a wall across a window or door opening.  
Jamb The vertical side of a door or window.  
Gable A roof consisting of two oppositely sloping planes that intersects at a level ridge.  
Rafter A framing member that runs up and down the slope of a steep roof.  
Baluster One of a series of short posts or pillars that make up a Balustrade and support the rail at the top and stand on the base at the bottom.  
Tread The horizontal portion of a stair which a user places their foot on.  
Riser The vertical portion of a stair.  
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