Wood has been used in construction for thousands of years and is still one of the most widely used building materials. Certain properties of wood can be complex in terms of use for construction, but despite this, engineers have successfully harnessed this natural resource to build a variety of structures. From houses to boats and other shelters, as well as furniture and décor, the construction industry has exploited the potential of wood to the fullest. Wood is favoured as a material because of the wide variety of properties depending on type. It is readily available and economically competitive, as well as being extremely strong in relation to its weight. Wood is generally classified as hardwood and softwood. Hardwood is typically heavier and denser than softwood and is usually utilised for construction of walls, ceilings and floors. The highest possible grade of hardwood contains 83% usable material on one face and is suitable for high- quality furnishings, solid wood mouldings and interior joinery. Softwoods are generally used to make more of the inner structures to the frame of hardwoods, such as doors and window frames. It is also used to produce furniture. The words ‘lumber’ and ‘timber’ are often used to refer to wood used specifically in construction work, however there is debate as to which terms should apply to different scenarios. As a rule of thumb, wood which is smaller than five inches wide by five inches thick is referred to as lumber. These pieces are usually machine-planed and sawn for certain dimensions primarily being used in residential construction. Pieces of wood over the lumber dimensions, regardless of length are timber, although any timber pieces that are more than eight inches wide and eight inches thick are called beams. As timber is usually larger in dimension it is used for the frames of structures in buildings and bridges, as well as being used in railroad ties, mine shaft support and crossbeams on utility poles.