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Defects due to wear and tear

Timber wear and tear in inevitable. However, abnormal wear can be a cause for concern.
© Universiti Malaya

Timber members that were designed well and properly used can last a lifetime.

However, over time the timber members especially floors can start to show signs of wear and tear in the form of scratch and scuff marks, bowing and cupping, and rot damage.

What we are concerned with here, are premature wear and tear of timber elements.

Excessive loads can cause timber structural members to sag. This can be caused due to changes in building use or usage not as intended or designed post-construction. In the case of roofs normally, sagging can be induced by the change of covering materials specification that weighs significantly more than the structural timber was originally designed for.

Incorrect supports can also cause sagging in timber members. Supporting column spacing intervals have to be designed and specified according to the structural strength of the timber. Similarly, joists that support timber floor that are spaced too widely can induce repeated movement causing nails or fasteners to be pushed outwards or the nails themselves starts to dig into the floorboards.

Extreme loadings can cause timber beams to fail at the joinery points. It is important to make sure where timber structures are joint, they are designed to occur at the support points such as directly on the columns.

Premature rot

Despite treatments, timber may be prone to disintegration where the protective finish fails from excessive and repeated abrasion. An example is a case of doors not being hung plumb and scraping against the floor. After repeated opening and closing, the protective finish is worn prematurely and with exposure to excessive moisture, the timber door starts to absorb water up to the point that it fails from rot.

© Universiti Malaya
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