1964_BUILDING_(CONSTRUCTION)_REGULATIONS — Page 125

HK Historical Laws 香港歷史法例 All AI Reviewed

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1985 Ed.]

Building (Construction) Regulations

[CAP. 123

B 125

[Subsidiary]

Construction and Materials

Concrete blocks

Plastered at least 12.5 mm thick

on each side and 1 cell in wall thickness:-

Minimum thickness in mm

(excluding plaster)

for period of

hours hours hour hour

Class 1 Aggregate

Class 2 Aggregate

225

115 75 65

225

Gypsum blocks

Not less than 70 per cent solid:-

No plaster

100

Plastered at least 12.5 mm

thick on each side

CAVITY WALL

CONSTRUCTION-

Walls constructed in accordance

with regulation 60:

(a) of solid bricks or blocks of clay, concrete or sand lime:-

thickness of each leaf

(b) with outer leaf not less than 100 mm thick of solid bricks or blocks of clay, concrete or sand/lime:-

(i) Thickness of inner

leaf of solid or hollow concrete blocks of: Class 1 Aggregate

(ii) Thickness of inner leaf of hollow clay or solid or hollow concrete blocks of Class 2 Aggregate

STEEL OR TIMBER

STUDDING-

Plaster on metal

or timber lathing

Plaster board

with or without

gypsum plaster

Portland cement plaster, Portland cement-lime plaster or gypsum plaster

9.5 mm thick plaster board on

each side

9.5 mm thick perforated plaster

board on each side

Two 9.5 mm thick plaster boards

on each side

12.5 mm thick plaster board on

each side

19 mm thick plaster board on each

side

100

12.5

(neat, single coat)

12.5

Nil

9.5

Nil

In this Table:-

Class 1 Aggregate means foamed slag, pumice, blast furnace slag, crushed brick

and burnt clay products, well burned clinker, crushed limestone.

Class 2 Aggregate means flint, gravel, granite and all crushed natural stones

other than limestone.

Page 125

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Concrete blocks2Plastered at least 12.5 mm thickon each side and 1 cell in wall thickness:-Minimum thickness in mm(excluding plaster)for period of344:hours hours hour hour7550Plastered at least 12.5 mmthick on each side755050with regulation 60:(a) of solid bricks or blocks of clay, concrete or sand lime:-thickness of each leaf(b) with outer leaf not less than 100 mm thick of solid bricks or blocks of clay, concrete or sand/lime:-(i) Thickness of innerleaf of solid or hollow concrete blocks of: Class 1 Aggregate(ii) Thickness of inner leaf of hollow clay or solid or hollow concrete blocks of Class 2 AggregateSTEEL OR TIMBERSTUDDING-Plaster on metalPlaster boardwith or withoutgypsum plasterPortland cement plaster, Portland cement-lime plaster or gypsum plaster9.5 mm thick plaster board oneach side9.5 mm thick perforated plaster751912.5(neat, single coat)12.5Nil9.5NilNilIn this Table:-Class 1 Aggregate means foamed slag, pumice, blast furnace slag, crushed brickand burnt clay products, well burned clinker, crushed limestone.Class 2 Aggregate means flint, gravel, granite and all crushed natural stonesother than limestone.Page 125

Baseline (Original)

Concrete blocks2Plastered at least 12.5 mm thickon each side and I cell in wall thickness:-Minimum thickness in mm(excluding plaster)for period ofبيا3454:hours hours hour hour7550Plastered at least 12.5 mmthick on cach side755050with regulation 60:(a) of solid bricks or blocks of clay, concrete or sand lime:-thickness of each leaf(b) with outer leaf. not less than 100 mm thick of solid bricks or blocks/of clay. concrete or sand/lime:-(i) Thickness/ of inner.leaf of solid or hollow concrete blocks of: Class 1 Aggregate(ii) Thickness of inner leaf of hollow clay or solid or hollow concrete blocks of Class 21 AggregateSTEEL OR TIMBERSTUDDING-Plaster on metalPlaster boardwith or withoutgypsum plasterPortland cement plaster. Portland cement-lime plaster or gypsum plaster9.5 mm thick plaster board oneach side9.5 mm thick perforated plaster751912.5(neat. single cout!12.5Nil9.5!NilNilIn this Table:-Class 1 Aggregate means foamed slag, pumice, blast furnace slag, crushed brickand burnt clay products, well burned clinker, crushed limestone.Class 2 Aggregate means flint, gravel, granite and all crushed natural stonesother than limestone.Page 125!

2026-05-04 08:25:23 · Baseline

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1985 Ed.]

Building (Construction) Regulations

[CAP. 123

B 125

[Subsidiary]

Construction and Materials

Concrete blocks

Plastered at least 12.5 mm thick

on each side and I cell in wall thickness:-

Minimum thickness in mm

(excluding plaster)

for period of

بيا

hours hours hour hour

Class 1 Aggregate

Class 2 Aggregate

225

115 75 65

225

Gypsum blocks

Not less than 70 per cent solid:-

No plaster

100

Plastered at least 12.5 mm

thick on cach side

CAVITY WALL

CONSTRUCTION-

Walls constructed in accordance

with regulation 60:

(a) of solid bricks or blocks of clay, concrete or sand lime:-

thickness of each leaf

(b) with outer leaf. not less than 100 mm thick of solid bricks or blocks/of clay. concrete or sand/lime:-

(i) Thickness / of inner.

leaf of solid or hollow concrete blocks of: Class 1 Aggregate

(ii) Thickness of inner leaf of hollow clay or solid or hollow concrete blocks of Class 21 Aggregate

STEEL OR TIMBER

STUDDING-

Plaster on metal

or timber lathing

Plaster board

with or without

gypsum plaster

Portland cement plaster. Portland cement-lime plaster or gypsum plaster

9.5 mm thick plaster board on

each side

9.5 mm thick perforated plaster

board on each side

Two 9.5 mm thick plaster boards

on each side

12.5 mm thick plaster board on

each side

19 mm thick plaster board on each

side

100

12.5

(neat. single cout!

12.5

Nil

9.5! Nil

Nil

In this Table:-

Class 1 Aggregate means foamed slag, pumice, blast furnace slag, crushed brick

and burnt clay products, well burned clinker, crushed limestone.

Class 2 Aggregate means flint, gravel, granite and all crushed natural stones

other than limestone.

Page 125!

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