A routine inspection of structural elements can identify potentially damaging problems in timber. A knowledge of properties which affect the strength characteristics and the durability should be applied to the inspection procedure. Visual observations should be combined with nondestructive techniques in the inspection program [2].

Assessment of in-situ condition of timber was tried using a number of non-destructive evaluation techniques. Techniques such as Schmidt rebound Hammer, Electron Spin Resonance spectroscopy, X-ray Diffraction and Sound Level Meter were found to be of little help in evaluation of structural properties of different species of timber. Tests on a number of samples from six species of timber have shown that Ultrasonic Pulse Method can be used to assess the strength characteristics of timber [3]. Ultrasonic tests were carried out to determine the effect of specific gravity, moisture, content, and internal voids on the pulse velocity. A relationship between pulse velocity and compressive strength parallel to grain was derived, using which a condition- rating method was proposed. Validity of the proposed technique was established by the assessment of deteriorated structural timber elements in a 140-year old church building in Madras. REFERENCES

1. Ashurust, J. N. Practical Building Conservation, Vol. 5, Wood, English Heritage technical Handbook, Grover Technical Press, England, 1988.
2. freas, A. D., "Inspection", Wood Structures: A Guide and Commentary, ASCE Spl. Pub., ASCE, New York, 1982.
3. Shaji, T. L., Nondestructive Evaluation and Inspection of Timber components in Historic Building, M. Tech Thesis, Civil Engg. Dept. IIT Madras, 1993