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Bld62003 timber mak
- 1. TIMBER BLD62003 BUILDING MATERIALS BACHELOR OF QUANTITY SURVEYING (HONS.) BLD62003_MAK_TIMBER 1
- 2. INTRODUCTION • One of the ancient building materials. • Used in almost all parts of the world for centuries. • Loved by all as it is strong and stiff, yet by far the least dense material in the construction sector. Hōryū-ji ( Temple Of The Flourishing Law) year 607 BLD62003_MAK_TIMBER 2
- 3. WHAT IS TIMBER? • Natural material • Renewable source • Aesthetically beautiful with various colors, tones and grains • Creates warm feeling • Has natural thermal insulation qualities • High strength relative to its weight • A degree of natural durability BLD62003_MAK_TIMBER 3
- 5. TYPES OF TIMBER in MALAYSIA BLD62003_MAK_TIMBER 5 AGATIS ALBAZIA KAPUR MEMPHENING NYATOH SERAYA
- 6. 20 TYPES OF MOST POPULAR TIMBER in MALAYSIA BLD62003_MAK_TIMBER 6 • Balau (Shorea spp.) • Bintangor (Calophyllum spp.) • Chengal (Neobalanocarpus heimii) • Dark Red Meranti (Shorea spp.) • Gerutu (Parashorea spp.) • Kasai (Pometia spp.) • Kelat (Syzygium spp.) • Keledang (Artocarpus spp.) • Keruing (Dipterocarpus spp.) • Mengkulang (Heritiera spp.) • Merbau (Intsia spp.) • Nyatoh (Spp. of Sapotaceae) • Kembang Semangkok (Scaphium spp.) • Kempas (Koompassia malaccensis) • Red Balau (Shorea spp.) • Yellow Meranti (Shorea spp.) • Sepetir (Sindora spp.) • Mersawa (Anisoptera spp.) • Merpauh (Swintonia spp.) • Heveawood (Hevea brasiliensis) See more at: http://mtc.com.my/timber-products/#sthash.A8VCa1Zv.dpuf http://www.etawau.com/Timber/Wood.htm
- 7. PRICES OF TIMBER IN M’SIA SPECIES LOGS/TON SAWNTIMBER/M3 18" UP GMS STRIPS SCANTLINGS HEAVY HARDWOOD Chengal 4,000 6,638 2,966 8,828 Balau 2,820 2,825 2,12 6 3,531 Red Balau 2,500 2,966 1,977 3,178 Merbau 2,650 3,778 3,107 2,772 Mixed Heavy Hardwood 830 812 784 742 BLD62003_MAK_TIMBER 7 AVERAGE DOMESTIC PRICES OF LOGS, SAWN TIMBER, PLYWOOD AND MDF IN PENINSULAR MALAYSIA (JUNE 2015) * All prices are in Ringgit Malaysia (RM) * All prices are indicative only
- 8. PRICES OF TIMBER IN M’SIA BLD62003_MAK_TIMBER 8 AVERAGE DOMESTIC PRICES OF LOGS, SAWN TIMBER, PLYWOOD AND MDF IN PENINSULAR MALAYSIA (JUNE 2015) * All prices are in Ringgit Malaysia (RM) * All prices are indicative only MEDIUM HARDWOOD Keruing 1,400 1,766 1,271 2,203 Kempas 1,210 1,780 1,695 2,010 Kapur 1,700 2,248 752 2,331 Mengkulang 1,100 1,412 925 1,575 Tualang 1,310 2,260 1,377 2,295
- 9. PRICES OF TIMBER IN M’SIA BLD62003_MAK_TIMBER 9 AVERAGE DOMESTIC PRICES OF LOGS, SAWN TIMBER, PLYWOOD AND MDF IN PENINSULAR MALAYSIA (JUNE 2015) * All prices are in Ringgit Malaysia (RM) * All prices are indicative only LIGHT HARDWOOD Dark Red Meranti 1,900 2,190 1,601 2,754 Red Meranti 1,760 1,589 1,271 1,624 Yellow Meranti 1,150 1,400 1,165 1,400 White Meranti 1,040 2,119 1,521 1,695 Mersawa 1,470 1,483 989 1,412 Nyatoh 900 777 565 1,201 Sepetir 850 1,107 918 1,118 Jelutong 1,000 1,391 1,285 1,540 Mixed Hardwood 1,150 812 706 648
- 10. PRICES OF TIMBER IN M’SIA BLD62003_MAK_TIMBER 10 AVERAGE DOMESTIC PRICES OF LOGS, SAWN TIMBER, PLYWOOD AND MDF IN PENINSULAR MALAYSIA (JUNE 2015) * All prices are in Ringgit Malaysia (RM) * All prices are indicative only MALAYSIAN RUBBERWOOD Hevea brasiliensis LOGS/TON SAWN TIMBER/M3 160 1" X 1" 2" X 2" 3" X 3" 4" X 4" 706 1,045 1,080 1,186 PLYWOOD 4' X 8' (RM per piece) 4mm 6mm 9mm 12mm 14.60 22.00 34.50 41.50 MDF 4' X 8' (RM per piece) 4mm 6mm 9mm 12mm 12.10 15.80 21.70 28.10 http://www.mtib.gov.my/index.php?option=com_content&view=article&id=8 7&Itemid=88&lang=en
- 15. PROPERTIES OF TIMBER • Not an electricity or heat conductor • Highly combustible hence burns quickly • Varying weight in different sorts of wood compositions • Opaque/ solid • Not a renewable source of energy • Color: brown of slightly red • A biological material • A fuel – producing heat energy when burnt • Shrinks due to water loss through evaporation • The drier the timber is the stronger it will be • Some timber requires moisture to stabilize equilibrium with the outside air by exchanging moisture with relevant temperature & humidity BLD62003_MAK_TIMBER 15
- 17. • Timber is an orthotropic material; grows in a vertical manner. • Fibrous material • Cellular organic material made up mainly of cellulose. • Strength of wood does not depend on the length of fibers but on the thickness of the cell walls. • Wood’s finely porous structure make it a relatively suitable material for insulation BLD62003_MAK_TIMBER 17STRUCTURAL PROPERTIES
- 18. • Dimensional changes in wood may be affected by temperature and moisture. • Heating of wood results in an expansion due to high temperature but also a shrinkage due to the subsequent loss in moisture. • Timber is a poor conductor of heat(denser timbers are better conductors) • Corrosion resistant • Natural product, so it has color variations • High firmness with good elasticity • High absorption capacity • Naturally resistant to chemical action, making it a suitable building material in chemically adverse environments BLD62003_MAK_TIMBER 18PHYSICAL PROPERTIES
- 19. • Resistant to passage of electric current • Some species of wood are decay resistant and resist attack of insects such as termites. • For example: Cedars, Redwood, Cypress, Black walnut and Black locust. • • Cedar Cypress Black locust Red wood BLD62003_MAK_TIMBER 19
- 20. • Wood provides a good sound insulation when combined with other materials in construction. • Sound absorption values for wood differ with moisture content, direction of the grain and density. BLD62003_MAK_TIMBER 20ACOUSTICAL PROPERTIES
- 22. CHARACTERISTICS • Contains: i. 70% cellulose ii. 25% lignin (provides strength) iii. Extractive i.e tannin, starch, oil, resin, fat and wax • Categorized into 2 types: (i) Softwood; (ii) Hardwood. • But in Malaysia, they are categorized into 4 types. BLD62003_MAK_TIMBER 22 TIMBER Heavy hardwoods (Belian, Cengal) Medium Hardwoods (Rasak, jati, merbau) Light Hardwoods (Semangkok, Nyatoh) Softwood (Ramin)
- 24. FORMATION – 2 layers Darker brown lines at the center • Called the late wood, hardwood or summer wood • Dense than the lighter brown Lighter brown lines at the outmost layer • Called the early wood, sap wood or spring wood • Softer than the darker brown BLD62003_MAK_TIMBER 24
- 25. FORMATION – 2 Layers BLD62003_MAK_TIMBER 25 DARKER BROWN LINES LIGHTER BROWN LINES
- 26. Softwood VS. Hardwood Softwood Hardwood Definition Conifer trees, needle- shaped leaves that mostly grows in northern temperate zone. Mostly evergreen. Broad-leafed trees, which loses their leaves in autumn as they are deciduous. Growth rate Has a higher growth rate Has a lower growth rate Density Has a lower density, thus softer than hardwood Has a higher density Cost Less expensive More expensive Fire Resistance Better Poor Uses Wood ware (homes and cabins), furniture, finishes Flooring, furniture BLD62003_MAK_TIMBER 26
- 27. HARDWOOD BLD62003_MAK_TIMBER 27 BENEFITS: • Adds warmth and beauty • Can add lasting value to interior façade (home, office etc) • Offers great design flexibility • Does not retain dust, pollen and other allergens • Low maintenance • Enhances room décor and offers ageless beauty
- 28. HARDWOOD • Hardwoods are mainly obtained from deciduous trees. • Deciduous trees are also known as broad leaf trees. • Timber for engineering purpose is obtained from these trains as the trees have hard woods that are strong and are dark colored. • They are obtained from tress such as oak, walnut, teak etc. BLD62003_MAK_TIMBER 28
- 29. TEAK Properties: Teak is a hard hardwood, it is heavy and strong. It has a high durability and is strong in strength. Teak originated in India and Burma. Uses: Teak is used to build boats, cabinets, other furniture, flooring and decorative veneers. Other: It is best to use an oil finish when using teak. It can also be difficult to glue and its dust has known to be an irritant. AMERICAN BIRCH Properties: American Birch is a hard hardwood, it is heavy and strong but has a low durability. It originated from USA and Canada. Birch also finishes well. Uses: Making furniture, quality joinery, dowels and flooring. It is also used in the manufacture of plywood. ENGLISH ELM Properties: English Elm is a hardwood with an intermediate hardness. It has an intermediate weight and low durability. It finishes well but is not suitable for exterior work. Uses: Used for cabinet making, Windsor chairs, boat building, flooring and coffins HARDWOOD BLD62003_MAK_TIMBER 29
- 30. SOFTWOOD • Softwoods are mainly from coniferous tress. • Coniferous trees are also known as evergreen trees. • These kinds of trees bear softwood that are light in color, light in weight and weak. • They can be used for decorative purpose only. • They are obtained from trees such as larch, pine, spruce etc. BLD62003_MAK_TIMBER 30
- 31. DOUGLAS FIR Properties: Douglas- fir is a softwood, it Uses: Douglas-fir is commonly used in the construction industry. It has also been used for home built aircraft. They are also the most common Christmas tree in the USA WESTERN RED CEDAR Properties: Western Red Cedar is a lightweight softwood that has a high durability and finishes well. It originated from Canada, UK and the USA. It is weak and is soft. Uses: Garden sheds, greenhouses, exterior boardings, fencing and posts. Notes: When nailing Western Red Cedar it is best to use galvanised or copper nails. This timber is not a true cedar YELLOW PINE Properties: Yellow pine is a softwood that has an intermediate weight and is also strong. It also has a intermediate durability and finishes well. Uses: Construction work, shipbuilding, flooring, joinery work, crates and pallets SOFTWOOD BLD62003_MAK_TIMBER 31
- 32. TYPES OF TIMBER BLD62003_MAK_TIMBER 32 Timber Natural solid timber Engineered timber products Plywood Fiber boards Particle boards Block board Laminates Veneers
- 33. NATURAL SOLID TIMBER BLD62003_MAK_TIMBER 33 • The tree logs are converted into commercially feasible sizes. • It is easy to provide carpentry joints in solid timber • It is 100% recyclable material • Depending upon the type of tree it is generally hard, stiff & has high strength and durability • The age of timber furniture is longest : more the 50 years • Repair and maintenance is easy but regular maintenance is advisable • It requires less labor than metallic work and is easily available • It is likely to crack and decay if not properly seasoned and treated • It is not advisable if there is a risk of fire or regions of high humidity and natural storms
- 35. Conversion of Timber • A process of cutting logs into sections before seasoning. Type of Cuts A. Plain sawn / Through and through o Mostly produces tangentially sawn timber and some quarter sawn. o Most economical o The center of the tree (pith) is removed as it is soft and splits o Easily distort during seasoning BLD62003_MAK_TIMBER 35
- 36. PLAIN-SAWING i. Parallel cut of log into boards ii. Varies in grain pattern iii. Tend to twist and wear unevenly Advantage: The most economical way of sawing logs - it gives the greatest possible amount of lumber with the least waste. Disadvantage. Plain sawed lumber usually warps very badly. Effect of warping of lumber. • There is always considerable moisture in the form of sap. • When the tree is cut down, the sap ceases to circulate, and the moisture in the log begins to evaporate. • As the log dries, all of the concentric rings, representing the annual growths, become a little shorter and thus cause the log to crack. • If it has been sawed into boards it will, of course, dry even more rapidly, causing the portion of the rings in each board to shorten considerably, and thus bend or warp the board, as shown in the illustration. PLAIN SAWN BLD62003_MAK_TIMBER 36
- 37. B. Quarter Sawn • Timber is cut with the growth rings meeting the surface not less than 45 degrees. • More decorative and does not distort easily • Produces more waste. • More expensive. BLD62003_MAK_TIMBER 37
- 38. • In order to overcome this tendency to warp, another method of sawing has been devised. • This method also adds great beauty to the appearance of the boards by exposing the medullary rays. • The log is usually cut into quarters as the first operation. • There are a number of different methods of quarter sawing, but they all have the same purpose in view, that of cutting the boards as nearly as possible in a direct line from the bark to the heart. QUARTER SAWING BLD62003_MAK_TIMBER 38
- 39. QUARTER SAWING BLD62003_MAK_TIMBER 39 Section A • Each board perfectly quartered • Very wasteful: so many wedge-shaped pieces that cannot be used Section B • Fairly good results but not as perfect as A. • A wasteful method on account of the great number of small pieces left. Section C & D • Very good quartered effect • Common methods of producing quartered oak lumber. • The irregular pieces left at the corners are usually cut into stock of some other character.
- 41. Rift-sawn boards are probably the least desirable of all the cuts. This is because these cuts can vary quite a bit depending on where in the log they are cut. They also tend to "move" in two directions with makes them poor choices for flooring, table tops and decking. Rift cut is often left for building materials like 2x4, 2x6s, 4x4 and so on. This does not mean that good quality hardwoods are not available in rift-sawn cuts, only that it is often not the ideal cut BLD62003_MAK_TIMBER 41 RIFT SAWING
- 43. Seasoning • A process where the wood is dried or moisture content is reduced to a level where it is suitable to be used. Types of Seasoning A. Air Seasoning o Timber, protected from the ground and rain are stack in layers separated by strips of wood (stickers) which control the passage of air. o The warm air, circulated by the wind removes the moisture. o Timber ends are protected by waterproof coatings to avoid splitting. BLD62003_MAK_TIMBER 43
- 44. B. Kiln Drying • Heating timbers in a closed chamber with precise temperature and humidity • Timber is not degraded • Timber is normally air dried to a fiber saturation and then kiln dried. BLD62003_MAK_TIMBER 44
- 46. VIDEO ON KILN DRYING PROCESS BLD62003_MAK_TIMBER 46
- 48. ADVANTAGES & DISADVANTAGES OF TIMBER BLD62003_MAK_TIMBER 48
- 49. ADVANTAGES BLD62003_MAK_TIMBER 49 Renewable resource High electrical resistance Suitable for construction in all types of climatic zones Reduce waste Improve efficiency of material usage
- 50. BLD62003_MAK_TIMBER 50 Good thermal insulation Good sound absorption Compatible with traditional skills Requires less energy High strength Reduce environmental problems caused by excessive timber harvesting Save cost and waste of sawing Long span of life time Demolished timber structures can be cycled as building material (i.e burnt as fuelwood)
- 51. • High costs and diminishing supplies of timber • Distortions, shrinkage and splitting. Distortions Shrinkage Splitting DISADVANTAGES OF TIMBER BLD62003_MAK_TIMBER 51
- 52. • Extreme hardness of some dried timbers. • Discoloration, brittle and erosion. Discoloration Erosion • High toxicity of chemical preservatives. DISADVANTAGES OF TIMBER BLD62003_MAK_TIMBER 52
- 53. • Wood Decay (Caused of Mold and Fungal Stains) Mold FungiBLD62003_MAK_TIMBER 53 DISADVANTAGES OF TIMBER
- 54. • Termites • Marine Borers BLD62003_MAK_TIMBER 54 DISADVANTAGES OF TIMBER
- 56. Treatments and Protections • Known as control in the case of wood that has already been infested, or as preventive protection, to ensure no infestation takes place. Methods of Protection • Only timber that has been well dried (moisture content less than 20%) should be used. • Fire-retardant treatment (FRT) is done by placing lumber in a vessel and impregnating it under pressure with chemical salts to reduce its combustibility. • Wood preservatives (pesticides, insecticides) are used , but used at a limit to avoid environmental damage. BLD62003_MAK_TIMBER 56
- 57. • Waterborne salts (wood preservative) are most widely used. • Most common is the chromatid copper arsenate (CCA) • These preservative are either brushed or sprayed onto wood. However, pressure impregnation last the longest as it drives the chemical deeply into the fibers. BLD62003_MAK_TIMBER 57
- 60. APPLICATION OF TIMBER • Building structural • Cabinet & furniture • Internal finishes • Construction i. Light frame timber construction ii. Heavy frame timber construction • Wood panel products BLD62003_MAK_TIMBER 60
- 61. VENEER WOOD PANEL • Thin sheets of wood cut form a log. • Thinner than 3mm thick. • Glued onto core panels (typically, wood, particle board or medium-density fiberboard) to produce flat panels such as doors, tops and panels for cabinets, parquet floors and parts of furniture. • Hand selected & assembled panel, made to order. • These panels do not require any extra finishing BLD62003_MAK_TIMBER 61
- 62. LAMINATE WOOD PANEL • Manufactured timber made from thin sheets of substrates or wood veneer. • It is similar to the more widely used plywood, except that it has a plastic, protective layer on one or both sides. • Can be produced as large as possible for beams or in thin layers of furniture. • Reasons to laminate wood: size, shape and quality. • Carry out seasoning before laminate the wood. BLD62003_MAK_TIMBER 62
- 63. LAMINATE FLOORING - Video BLD62003_MAK_TIMBER 63
- 64. PLYWOOD • Made by gluing together thin veneers or piles of softwood or hardwood. • The more veneer the stronger the plywood. • Types of glue and veneers determine suitability for application. • Fresh qualities vary where some have attractive grains whilst some contain knots. • Maybe used as interior or exterior purposes. • Different grades are used for internal and external use depending on water resistance of the glue used to stick the piles together. • Used to form pitched roofs or form folded- plate roof structures. • Lower grade materials used as formwork for in-situ concrete. BLD62003_MAK_TIMBER 64
- 65. PLYWOOD • REGULAR GRADE PLYWOOD Temporary usage • COMMERCIAL PLYWOOD Also known as interior grade or moisture resistant (MR) grade plywood Used for making furniture that is unlikely to get wet • MARINE PLYWOOD Superior quality and also expensive Used for making furniture or products that are subjected to prolonged water exposure Used mainly for industrial purposes and boat building. • WATER PROOF PLYWOOD Also known as exterior grade or Boiling water resistant (BWR) grade plywood. Used for making furniture that is likely to get wet i.e. kitchen furniture. BLD62003_MAK_TIMBER 65
- 78. 1. Wax • Type : or • Characteristic : look like freshly cut unfinished wood, smooth feel, softer than lacquers and varnishes. • Protection : melt at low temperature, little protection against scratches and wear, not penetrating the wood, prevent oxidation. BLD62003_MAK_TIMBER 78
- 79. 2. Paint • Type : • Characteristic : bright white appearance, not preservative, appear in most of the building • Protection : protect wood from weathering, conceal some surface defeat cleanable surface with many color to retard penetration of water BLD62003_MAK_TIMBER 79
- 80. 3. Solid color stain • Type : • Characteristic : long lasting, opaque surface, vibrant color • Protection : waterproof, UV protection BLD62003_MAK_TIMBER 80
- 82. • Small strips of wood are joined together with glue to form a larger element. • Stable • High Bearing Capacity • It can used as a building structure or finishing element. BLD62003_MAK_TIMBER 82 GLUED LAMINATED TIMBER (GLULAM)
- 83. Laminated Veneer Lumber (Microlam) • It uses many layers of thin wood treated with adhesives. • Economical • Lower tendency to shrink or twist • Suitable in columns, beams and purlins BLD62003_MAK_TIMBER 83
- 84. Plywood • Manufactured by laminating a series of thin timber layer • Grains direction are at right angles to each other • Used as a lining, flooring surface, complex roof structures, formwork BLD62003_MAK_TIMBER 84
- 85. Wood Particleboard (Chipboard) • Uses wood waste or forest thinning, which are converted into wood chips. • Made by compressing the sawdust and plane shavings with adhesives. • Used in furniture industry BLD62003_MAK_TIMBER 85
- 86. Cement-bonded particleboard • Manufactured from a mixture of wood particles and cement. • Contains 75% of cement to fill up voids • Good sound-insulation • Resistant to fire, water and fungal • Used as soffits, roofing, and flooring BLD62003_MAK_TIMBER 86
- 87. Oriented Strand Board (OSB) • Made from long strands of wood compressed and glued into three to five layers. • Strands are oriented in the same method as plywood. • Used for sheathing and subflooring of light frame wood buildings. BLD62003_MAK_TIMBER 87
- 88. Fiberboard • Fine-grained board made of wood fibers and synthetic resin binders. Medium Density Fiberboard o Manufactured by dry wood fibers in addition of adhesives o Used as furniture panels and as internal load bearing applications. BLD62003_MAK_TIMBER 88
- 89. Hardboard (HDF) • Densest fiberboard • Density of 900kg/𝑚3 • Used as paneling, wall and ceilings linings, floor underlays and furniture. BLD62003_MAK_TIMBER 89
- 90. Comparison of Timber Products Laminated Veneer Lumber (LVL) and Plywood LVL Plywood Orientation of Grains (Veneer Layers) Grains are parallel to each other Grains are in a direction that are perpendicular to each other to have uniform strength and reduce moisture movement BLD62003_MAK_TIMBER 90 LVL vs. Plywood
- 91. Plywood and Oriented Strand Board (OSB) Plywood OSB Composition of Material Thin layers of veneers that are glued and laminated. Dried wood strands mixed with adhesives an wax to form thick mats. Cost More expensive Less expensive Economical Uses good logs called peelers Uses small trees and branches BLD62003_MAK_TIMBER 91 Plywood vs. OSB
- 92. Particleboard and Fiberboard Particleboard Fiberboard Materials used Wood dust Wood fibers Durability Weaker Stronger Ability to mold Hard to mold as it is easily chipped Easy to mold into shapes as it is hard to chip or break BLD62003_MAK_TIMBER 92
- 94. Wood Defect Features Caused By Effect Solution Blue Stain A bluish gray discoloration on the woods surface. This feature is most common in woods like Holly, Pine, and Sycamore. Mold that grows in warm and moist area, usually poorly ventilated. Discoloration of wood. Can be cut off, placed out of sight, or concealed with a dark stain. Bow A curve along the face of a board that usually runs from end to end. Improper storage. Usually moisture evaporation from one side and not the other. Stock is difficult to work with and cut. Cut in to smaller pieced, even out on a jointer, or nail (screws are better) in place with bow bulging out. Checks or Splits Breaks at the end of a board that run along the grain. Checks and splits are usually restricted to the end of a board. Rapid Drying. Can effect the strength and appearance of the board. Should be cut off or worked around. BLD62003_MAK_TIMBER 94
- 95. Blue Stain Checks or splits Worm hole Dead /Loose knotGum, Sap, or Pitch Cup BLD62003_MAK_TIMBER 95
- 96. Wood Defect Features Caused By Effect Solution Crook Warping along the edge from one end to the other. This is most common in wood that was cut from the center of the tree near the pith. Can be caused by improper drying and storage or the presence of reaction wood. Can be difficult to work with. The higher spots can be cut away on a table saw or jointer using a special jig. Cup Warping along the face of a board from edge to edge. This defect is most common of plain- sawn lumber. This defect can be caused when one board face dries at a faster rate than the other. Stock can be difficult to work with. Trying to "force it flat" can cause cracking along the grain. You can try allowing the board to dry at the same moisture content under pressure, rip it into smaller pieces on a table saw, or use a jointer to remove the high spots. Dead or Loose Knot A dark, usually loose knot. This is caused by a dead branch that was not fully integrated into the tree before it was cut down. Can mar the appearance of the wood, fall out, become loose, or weaken stock. Should be cut out, around, or glued in place and filled with a wood putty. Gum, Sap, or Pitch Accumulations of a resinous liquid on the surface or in pockets below the surface of wood. Injury to the tree. May cause difficulty when finishing. Should either be cut off or scraped out and filled. BLD62003_MAK_TIMBER 96
- 97. Machine Burn Dark streaks along the face of a board. Usually caused by planer blades that are dull or spun on a part of the board for too long. Discoloration to the surface. Sometimes the burn can penetrate into the board. Can be sanded off or cut down with a jointer. The depth of the board often determines the amount of work needed. Ring check Breaks in the wood along the annual growth rings. Improper drying or damage during transport. Can effect strength or appearance. Should be cut around, place out of sight, or glued down. Tight knot A know which is tightly integrated into the surrounding wood. This was once a branch that was incorporated into the tree as its girth increased. Does not effect the lumber's strength. May be removed for appearance purposes. Some lumber such as Knotty Pine, is highly prized for this feature. Twist Warping in lumber where the ends twist in opposite directions. (Like twisting a towel) Growing conditions, uneven drying or the presence of wood reaction. Can be difficult to work with. Can be cut into shorter boards or the high spots can be removed on a jointer. Wormholes Small holes in the wood. This is caused by insects boring through the wood. Can be used to simulate old or wormy wood. Cut around worm holes or uses as is for decorative purposes. Be sure the insects are dead. Wood Defect Features Caused By Effect Solution BLD62003_MAK_TIMBER 97
- 113. ADDITIONAL INFO ON SAWING TRUNKS BLD62003_MAK_TIMBER 113
- 120. References 1. Book References Allen, E. and Iano, J. 2009. Fundamentals of Building Construction : Materials and Methods. 5th ed. Hoboken: John Wiley & Sons Inc. American Institute of Timber Construction, 2005. Timber Construction Manual 5th ed., John Wiley & Sons, INC. BLD62003_MAK_TIMBER 120
- 121. Lyons, A., 2007. Materials for Architects & Builders. 4th ed. Oxford: Elsevier Ltd. Slavid, R., 2009. Wood Architecture, Laurance King Publishing Ltd. Spence, WP., and Kultermann, E., 2011. Construction Materials, Methods, and Techniques: Building for A Sustainable Future 3rd ed. Cengage Learning. BLD62003_MAK_TIMBER 121
- 122. Steiger, L., 2007. Basics Timber Construction, Birkhauser. Stulz, R. and Mukerji, K., 1993. Appropriate Building Materials. Oxford: Intermediate Technology Publications. Torre, F., 2008. Materials: A Sourcebook for Walls and Floors, Steward, Tabori & Chang. BLD62003_MAK_TIMBER 122
- 123. TUTORIAL QUESTIONS • Explain TWO (2) types of the conversion of timbers. • Differentiate FIVE (5) characteristics of softwood and hardwood. • Explain FIVE (5) examples of Natural and Seasoning timber defects, respectively. • Describe THREE (3) applications of timber. • Name and explain TWO (2) types of timber seasoning. BLD62003_MAK_TIMBER 123