• What are cover blocks?

Cover blocks are used to maintain a specified
distance between the TMT rebar and the
shuttering. (Cover blocks for slab)

  • Why we must use cover blocks?

– When doing RCC work it is important to
embed the steel in the concrete (also known
as cover) so that the rebar doesn’t corrode
and to provide fire protection to the rebar.

– If we don’t provide the recommended cover
the rebar will corrode with time and will
ultimately result in premature failure of the

– Thus using cover blocks enhances the life of
the structure significantly without adding
much to the cost

  • What is the right amount of cover?

-The right amount of cover is determined by the application and the
environment (e.g., is the RCC under water, etc.)

-In normal environments, following are typical covers recommended:

ApplicationCover (in mm)
Slab15-20-25 mm
Beam25-30 mm
Columm25 mm
Foundation35-50-75 mm