Timbering is a method of providing temporary support to the side of the trench and is sometimes called planking and strutting. It is a method to prevent trench side soil against the collapse. If the soil is not hard then during deep excavation the sides of the trench collapse.
The sides of the trench are timbering to prevent collapse.
Question
General Construction What is Timbering of Foundation Trenches?
What is the  importance of timbering in trenches for foundations? What is Timbering of Foundation Trenches?
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