Wood

a short presentation on wood and its types

1. DEEPTASHREE SAHA INTERIOR DESIGN 4 th SEMESTER CONSTRUCTION MATERIALS edexcel logo sourcewww.colossaltraining.co.uk arch logo source : www.sholay.in

2. WOOD

3. What is construction material? Construction material is any material which is used for construction purposes . Many naturally occurring substances have been used to construct buildings : Clay Rocks Sand Wood Twigs Leaves Clay Stone Sand Twig

4. What is wood ? Wood  is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants   It has been used for thousands of years for both fuel and as a construction material .  It is an organic material, a natural composite  of cellulose fibers (which are strong in tension) embedded in a matrix of lignin which resists compression. 

5. Classification of wood

6. NATURAL WOOD

7. Where do we generally find wood ? fuel flooring furniture fuel utensils m usical instruments s ports equipments

8. Wood processing

9. Physical Properties   Wood rings Water content Colour Grains Knots

10. Classification of natural wood

11. Hard wood Hardwood  is wood from  dicot  angiosperm  trees The term may also be used for the trees from which the wood is derived; these are usually broad-leaved . In temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly  evergreen  Hardwoods are not necessarily harder than softwoods

12. Hard wood Characteristics Hardwoods have a more complex structure than softwoods D ark in colour Expensive Slower growth rate Higher density Heavy in weight More fire resistant than soft wood Strong in compression and tension

13. Hard wood Examples - Oak Light in colour Heavy Ring porous Open grain Hard to work with. When treated it looks classy and elegant

14. Hard wood Examples - Oak products

15. Hard wood Examples - Maple   Maple is so hard and resistant to shocks that it is often used for bowling alley floors .  Its diffuse evenly sized pores give the wood a fine texture and even grain . Maple that has a curly grain is often used for violin backs. Burls, leaf figure, and birds-eye figures found in maple are used extensively for veneers .

16. Hard wood Examples - Maple products

17. Hard wood Examples - Mahogany   An easy to work wood reddish brown in colour Expensive Strong  poorly defined annual rings may display stripe, ribbon, broken stripe, rope, ripple, mottle, fiddle back or blister figures excellent carving wood and finishes well

18. Hard wood Examples - Mahogany products

19. Hard wood Examples - Cherry   hard Strong Light to red-brown wood Resists warping and checking Easy to carve and polish

20. Hard wood Examples – Cherry products

21. Hard wood Examples – Rubber wood   light colour Medium density Usually from the tree of rubber plantation Advertised as eco-friendly wood Because It is not grown specially for timber but instead have timber as by product

22. Hard wood Examples – Rubber wood products

23. Soft wood Softwood  is wood from gymnosperm trees such as  conifers  Softwood is the source of about 80% of the world's production of  timber  Softwoods are not necessarily softer than hardwoods The woods of long leaf pine,  douglas fir, and yew are much harder in the mechanical sense than several hardwoods

24. Soft wood Characteristics Cheap comparative to hard wood Faster rate of growth Lower density Softer than hardwood Light in colour Light in weight Poor fire resistant Strength in tension but week in sheer

25. Soft wood Examples - Ash Hardwoods have a more complex structure than softwoods D ark in colour Expensive Slower growth rate Higher density Heavy in weight More fire resistant than soft wood Strong in compression and tension

26. Soft wood Examples – Ash wood products

27. Soft wood Examples - Pine   soft White or pale yellow in colour Light weight Straight grains Lack figures Resists shrinking and swelling knotty

28. Soft wood Examples – pine wood products

29. Soft wood Examples -Cedar   Knotty soft wood Red brown colour with light steaks Aromatic and moth repellant Popular wood for lining drawers, chests and boxes  Brittle wood

30. Soft wood Examples – cedar wood products

31. Soft wood Examples –Red wood   The best quality redwood comes from the heartwood which is resistant to deterioration due to sunlight, moisture and insects Redwood burls have a "cluster of eyes" figure. They are rare and valuable.

32. Soft wood Examples – redwood products

33. NATURAL WOOD seasoning

34. Reduces moisture content of wood There are two main reasons : Woodworking : when wood is used as a construction material, whether as a structural support in a building or in wood working objects, it will absorb or desorb moisture until it is in equilibrium with its surroundings. Equilibration (usually drying) causes unequal shrinkage in the wood, and can cause damage to the wood if equilibration occurs too rapidly. The equilibration must be controlled to prevent damage to the wood. Wood burning : when wood is burned, it is usually best to dry it first.

35. Over exploitation of natural wood on nature D eforestation Desertification Extinction of species Forced migration Soil erosion Ozone depletion Greenhouse gas increase Natural hazard and desert So Need for engineered wood arises

36. ENGINEERED WOOD

37.  Also called  composite wood ,  man-made wood , or  manufactured board Includes a range of derivative wood products which are manufactured by binding or fixing the strands, particles,  fibers , or veneers or boards of wood, together with adhesives, or other methods of fixation to form composite materials  Engineered wood products are used in a variety of applications, from home construction to commercial buildings to industrial products.

38. Engineered wood Plywood   Plywood  is a sheet material manufactured from thin layers or "plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another This alternation of the grain is called  cross-graining  and has several important benefits: it reduces the tendency of wood to split when nailed at the edges It reduces expansion and shrinkage, providing improved dimensional stability It makes the strength of the panel consistent across all directions.

39. Engineered wood Block board   Blockboard is a wood based panel, made up of a core of softwood strips glued together  The strips may be up to about 28mm wide and are placed edge to edge and sandwiched between veneers of softwood, hardwood or thin MDF or particleboard, glued under high pressure The internal strips are generally made of light weight poplar wood or spruce To achieve maximum strength, it is important to ensure that the core runs lengthways has very good screw holding it has a good resistance to warping.

40. Engineered wood Veneers    veneer  refers to thin slices of wood, usually thinner than 3 mm (1/8 inch), that typically are glued onto core panels  Veneer is obtained either by "peeling" the trunk of a tree or by slicing large rectangular blocks of wood known as flitches  The appearance of the grain and figure in wood comes from slicing through the growth rings of a tree and depends upon the angle at which the wood is sliced

41. Engineered wood Laminates    Lamination  is the technique of manufacturing a material in multiple layers, so that the composite material achieves improved strength, stability, sound insulation, appearance or other properties from the use of differing materials A laminate is usually permanently assembled by heat, pressure, welding, or adhesives

42.     also known as chipboard manufactured from wood chips, sawmill shavings, or even sawdust, and a synthetic resin or other suitable binder, which is pressed and extruded It  is a composite material Engineered wood Particle board

43.     made by breaking down hardwood or softwood residuals into wood fibres, often in a  delibrator , combining it with wax and a resin binder, and forming panels by applying high temperature and pressure  MDF is generally denser than plywood It is made up of separated fibres  stronger and much denser than particle board Engineered wood Medium Density Fiber board

44.    also called hardboard  made out of exploded wood fibres that have been highly compressed  It differs from particle board in that the bonding of the wood fibres requires no additional materials, although resin is often added Unlike particle board, it will not split or crack Engineered wood High Density Fiber board