To estimate steel from R.C.C.
structures when cover of concrete to reinforcement is not mentioned the minimum
standard cover to the reinforcement (exclusive of plaster or other decorative
finish) shall be as follows:
- At each end of reinforcing bar not less than 25 mm nor less than twice the diameter of such bar.
- For longitudinal reinforcing bar in a beam, not less 25 mm nor less than the diameter of such bar.
- For tensile, compressive, shear or other reinforcement in a slab not less than 15 mm nor less than the diameter of such bar.
- For a longitudinal reinforcing bar in a column not less than 40 mm nor less than the diameter of such bar. In the case of columns of minimum dimension of 200mm or under whose reinforcing bars do not exceed 12 mm a cover of 25 mm may be used.
- For any other reinforcement not less than 15 mm nor less than the diameter of such bar. Increased cover thickness may be provided when surfaces of concrete members are exposed to the action of harmful chemicals and such increase of cover may be between 15 mm and 50 mm.
- For reinforced concrete members totally immersed in sea water the cover shall be 40 mm more than that.
- For reinforced concrete members, periodically immersed in sea water or subject to sea spray, the cover of concrete shall be 50 mm more than that.
- For concrete of grade M 25 and above, the additional thickness of cover specified in above may be reduced to half. In all such cases the cover should not exceed 75 mm.
