When renovating an old house that consists of old timber structure, it is always essential to evaluate the structural integrity and load bearing capacity of the structure’s elements. This assessment must be done by professional experienced engineer simply because the evaluation report dictates the extent of remediation plan that could be sometimes costly and may result in unnecessary remediation work.
Timber structure that was not maintained properly during its life span tends to develop deterioration in its structural capacity and integrity. The most common reasons to this phenomenon are: fungal decay, insect infestations, over loading or mechanical damage. The structural engineer must understand how each of these harming states has been developed and how it affects the structure integrity. Base on this knowledge, the structural engineer would be able to draw appropriate rectification plan that tackles the source of the problem on one hand and reinforces the structure to cope with loads appropriate to its intent of use on the other hand within affordable budget limits. Moreover, the engineer shall provide maintenance plan to the building owner to avoid such a damage to occur again in the future.
Moisture is the greater enemy of timber structures. Fungal decay also known as rot fungi is the most prevalent condition in deteriorated timber structures, it thrives and grows when the surrounding area of the structure is humid and warm. The infected structure will lose mass and strength as decay progresses and the rot fungi digest the wood fibre.
Another dominant cause to structural impairment in timber structures can be associated with insect infestation that damage the wood from its core and diminish its structural strength capacity to none.
There are several species of insects that bore into or feed on wood tissue. One of the most common types is termites. They tunnel into a building below ground and climb up into the timber structure. They consume and digest wood tissues as they tunnel along the grain of a timber. The fatal damage to the timber cannot be seen as they avoid to breakthrough to the surface and leave the timber member intact from outside. The main difference between species of termites is in their rate of progress of damage they incur to the structure of the house.
The integrity assessment for an old house before renovation begins with a visual examination of the property to evaluate the extent of damage that has been made to the structure and to identify signs of structural impairments. An awl is a simple indispensible tool for identifying the depth and extent of damaged timber by examining the sound and stiffness of the element. Where more comprehensive probe is required, there are non-destructive evaluation systems (NDE) that provide better perception of the house structure condition.
At Engineering Vision we have gained extensive experience in providing comprehensive engineering solutions to wide variety of projects from extension and renovation of houses to restoration of heritage buildings.