Hong Kong Regulations

BUILDING (CONSTRUCTION) REGULATIONS - REGULATION 62

Minimum cover of reinforcement

(1) Subject to Part XV, the thickness of the concrete cover to reinforcement
(exclusive of plaster rendering or other applied covering or decorative
finish) shall not be less than the size of that reinforcement or the dimension
as specified in Table 11, whichever is the greater and the cover to the ends
of bars shall not be less than 25 mm.

TABLE 11

MINIMUM THICKNESS OF CONCRETE COVER TO REINFORCEMENT

Reinforced concrete Prestressed concrete
Conditions of exposure Conditions of exposure

Specified grade strength Moderate Severe Moderate Severe Slabs and walls in
enclosed buildings

20 25 30 35 40 45 mm
30
30
30
25
25
25 mm
--
40
35
30
30
30 mm
--
--
30
25
20
20 mm
--
--
35
30
25
25 mm
20
20
20
15
15
15

(2) In marine works or where the concrete is exposed to particularly corrosive
conditions or where the concrete is made with lightweight aggregates the cover
shall be suitably increased. (Enacted 1990)