timber breif notes,bc 5th sem
UNIT II--- TIMBER
• Timber is wood in any of its stage from felling to readiness for use as structural material for construction or wood pulp for paper production.
• Timber is supplied either in rough or finished.
• Rough timber is a rough material for furniture making and other items requiring additional cutting and shaping. It is available in many species, usually hardwoods but is also available in softwoods such as white pine, red pine and popular due to their low cost per board foot.
• Finished timber is supplied in standard sizes, mostly for the construction industry.
Factors affecting the strength of timber:
There are 5 basic factors affecting the strength of timber.
They are as follows-
• Wood specific gravity
• Slope of grain
• Presence of knots or holes
• Moisture content • Time
In modern construction timber-frame structure offers many benefits:
• It is rapidly erected
• It lends itself well to prefabrication, modular construction and mass-production
• Lends well to pre-fitting the frame usually in bent or wall-sections that are aligned with jig. This allows faster erection on site and more precise alignments. Such pre-fitting in the shop is independent of a machine or hand-cut production line. Valley and hip timbers are not typically pre-fitted.
• An "average"-sized timber-frame home can be erected within 2 to 3 days.
Treatment prior to installation of timber:
• Before installing, the worktop must be treated on both the surfaces.
• Particular attention must be paid to end grain edges, cutouts for sinks and all surfaces which are hidden after installation.
• If not done properly, the worktops may bow and split as a result.
• Oiling should be done at least three times, allowing the oil to dry.
• After installation the worktop must be oiled thoroughly.
• Always work the oil in the direction of the wood grain.
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