1. A passionate self-governing institute which believes in
loyalty and honesty towards its members and the
profession and subscribes to the principles of fairness
and transparency in all it’s activities and conduct with
the vison to stimulate the expression of design and the
application of technology in architecture.
15:28
1
9. DEFINITIONS
expansive soil
fine-grained soil the clay mineralogy of which is such that it
changes in volume to varying degrees in response to
changes in moisture content, i.e. the soil increases in
volume (heaves or swells) upon wetting up and decreases
in volume (shrinks) upon drying out
foundation
that part of a building which is in direct contact with, and is
intended to transmit loads to, the ground
9
10. foundation wall
that portion of a wall between the foundation and the top
of the lowest floor above such foundation
inherent hazard class IHC
classification system whereby a site is characterized in
terms of eight standard inherent hazard classes denoting
the likelihood of an event (sinkhole or subsidence)
occurring, as well as its predicted size (diameter)
10
11. sinkhole
feature that occurs suddenly and manifests itself as a hole
in the ground
slab-on-the-ground foundation
concrete floor that is supported on the ground, and that
incorporates lightly reinforced integral edge and internal
beams
soil horizon
layer of soil that has similar geotechnical properties
strip foundation
rectangular unreinforced or lightly reinforced concrete
foundation that supports masonry walls
11
12. type 1 masonry building
building not used for storage or industrial purposes, and
with masonry walls that are not supported by steel,
concrete or reinforced masonry columns
12
13. H1 GENERAL REQUIREMENT
1. The foundation of any building shall be designed and
constructed to safely transmit all the actions which can
reasonably be expected to occur from such building to the
ground and in such a manner that any local damage (including
cracking), deformation or vibration do not compromise the
efficient use of a building or the functioning of any element of
a building or equipment within a building
2. The requirement of sub-regulation (1) shall be deemed to be
satisfied where the design and construction of such foundation
complies with SANS 10400-H.
13
16. 4 Requirements
4.1 General
4.1.1 The functional regulation H1(1) contained in part H
of the National Building Regulations shall be deemed to be
satisfied where a geotechnical site investigation has been
carried out in accordance with the requirements of 4.2, and
the foundations of a building are in accordance with the
relevant requirements of
16
17. a) SANS 10400-B, and such foundations are designed to
suit site conditions by taking into account
1) all the information contained in the geotechnical site
investigations conducted in accordance with the
requirements of 4.2,
2) the shape, size and construction of the buildings, as
well as the layout and topography of the site,
3) the existing, previous and future vegetation,
4) differential movements,
5) the location of services, and
6) erosion,
provided that the occupancies classified as E4, H3, H4
and H5 also comply with the requirements of annex A;
17
18. b) 4.3 in the case of single-storey type 1 masonry buildings,
provided that in the case of dolomite land, the inherent
hazard class determined in accordance with SANS 1936-2
and dolomite area designation, determined in accordance
with the requirements of SANS 1936-1, are such that
precautionary measures in addition to those pertaining to
the prevention of the concentrated ingress of water into the
ground are not required to permit the construction of
buildings;
18
19. c) 4.4 in the case of free-standing walls and retaining walls,
subject to any soil improvements, by chemical or mechanical
means (or both) undertaken to improve the properties of
soils under the building, executed under the direction and
inspection of a competent person (geotechnical); or
d) 4.1.2 in SANS 10400-A:2010 and SANS 10400-B in the
case of all other buildings.
19
20. 4.1.2 In the case of type 1 masonry buildings, the following
information shall be stated immediately above the title block
in the drawings submitted to local authorities in terms of
SANS 10400-A
a) the site class designation, determined in accordance with
the requirements of 4.2; and
b) the category of expected damage (see SANS 10400-B), if
the design is based on category 2 expected damage.
20
21. 4.2 Geotechnical site investigations
4.2.1 Geotechnical site investigations shall be undertaken
under the direction of a competent person (geotechnical),
who shall document and formulate an opinion regarding the
parameters upon which the design of the foundations is to be
based and, in the case of single-storey or double storey type
1 masonry buildings, shall classify the site in accordance with
the descriptors contained in column 5 of table 1 and the
requirements of 4.2.3.
21
22. Damage due to heaving clays Damage due to
collapsing sands
22
23. 4.2.2 The competent person (geotechnical) shall document
and formulate all opinions in such a manner that a review by
an independent competent person (geotechnical), if
conducted on the same basic data, will arrive at a
substantially similar opinion.
4.2.3 Site class designations shall be derived from an
estimation of the expected range of total soil movements
experienced by single-storey and double-storey type 1
masonry buildings, where the foundation load on a
foundation that has a width that does not exceed 0,6 m in
respect of single storey buildings and 0,8 m in respect of
double-storey buildings, does not cause the soil bearing
pressure to exceed 50 kPa.
23
24. 4.2.4 The competent person (geotechnical) shall investigate
and advise on the necessity of installing subsurface drains on
sites
a) in marshy areas,
b) that have shallow water tables, and
c) that are to be terraced to the extent that the depth of cut
below original ground level exceeds 0,75 m.
24
26. 4.3 Standard foundation solutions for single-storey type 1
masonry buildings
4.3.1 Geotechnical solutions
4.3.1.1 Geotechnical solutions shall be designed by a
competent person (geotechnical) to reduce total soil
movements by, for example,
a) removing the soil horizon that gives rise to movements
outside of the range that a building can tolerate without
distress, and replacing this horizon with adequately
compacted inert material, or reusing the excavated
material in a compacted condition;
26
27. b) founding the foundations at a greater depth than is
commonly associated with normal construction, i.e. on a
suitable soil horizon situated below the problem soil
horizon; or
c) in-situ compaction.
27
28. 4.3.1.2 The competent person (geotechnical) shall take into
account the impact of a geotechnical solution on the
stormwater drainage of the site.
4.3.1.3 The competent person (geotechnical) shall inspect
the works during the implementation of the solution.
28
29. 4.3.1.4 A competent person (civil engineering) or competent
person (geotechnical) shall, in the case of deep strip
foundations for masonry walls (see annex B) on class C1, C2,
S1 and S2 sites,
a) specify any reinforcing of walls, foundations and floors
and precautionary measures that might be required to
minimize the cracking of the walls and floors; and
b) inspect and approve the founding horizon.
29
30. 4.3.1.5 A competent person (civil engineering) or competent
person (geotechnical) shall, in the case of soil rafts on class
H1, H2, H3, C1, C2, S1 and S2 sites and the compaction of
in-situ soils below individual footings on class C1, C2, S1 and
S2 sites
a) ensure, in the case of heaving soils, that the entire active
profile is removed, or that the remaining profile does not
produce surface heave movements in excess of those that
can be accommodated by the design solution adopted;
.
30
31. b) approve the founding material or, in the case of
compressible and collapsible soils, ensure that sufficient
material is removed to permit the use of the design
solution specified;
c) approve the backfill material and institute and review
appropriate quality control checks on the compaction
thereof; and
d) specify any reinforcing of walls, foundations and floors
and precautionary measures that might be required to
minimize the cracking of the walls and floors.
31
32. 4.3.2 Structural solutions
4.3.2.1 General
4.3.2.1.1 The requirements of 4.3.2 apply only in respect of
single-storey type 1 masonry buildings that comply with the
requirements of SANS 10400-K where
a) the height of the wall from the floor level to the top of an
external gable does not exceed 5,0 m;
b) the span of roof trusses or rafters (or both) between
supporting walls does not exceed 8,0 m;
32
33. c) the span of concrete roof slabs between supporting walls
does not exceed the dimensions given in figure 2;
d) the dead load (self-weight) of the roof covering of roofs
other than concrete slabs does not exceed 80 kg/m2;
e) the thickness of concrete roof slabs does not exceed 255
mm if of solid construction, or the equivalent mass if of
voided construction;
f) the height of foundation walls does not exceed 1,5 m; and
g) the height of fill beneath floor slabs does not exceed 1,0
m.
33
35. 4.3.2.1.2 Foundations shall be constructed in accordance
with the requirements of SANS 2001-CM2 and in such a
manner that the bed joint thickness of the first masonry
course above the foundation is not less than 5 mm and not
greater than 40 mm.
4.3.2.1.3 Floor slabs and related fills shall be in accordance
with the relevant requirements of SANS 10400-J.
35
36. 4.3.2.1.4 Masonry walls shall be so located that the distances
between the walls and the centre(s) of any existing shrubs or
tree trunks are not closer than those set out in table 2.
On sites designated as H1 in accordance with the
requirements of 4.2, such distance shall not be less than
0,75 × mature height of a tree.
It shall not be less than 1,0 × mature height of a tree on H2
sites, and 1,5 × mature height of a tree on H3 sites.
36
39. 4.3.2.1.5 On sloping sites steeper than 1:4 where landslip is
not a consideration, the site shall be cut or backfilled (or
both) and compacted to not less than 93 % MOD AASHTO
density at −1 % to +2 % of optimum moisture content
(OMC) and benched into the in-situ material, under the
supervision of a competent person (civil engineering) such
that the fill (see figures 3 and 4)
39
40. a) extends at least 1 m beyond the face of the structure and
has a side slope not steeper than 1:1 with respect to the
horizontal, and the slope of the fill is covered with a
lightly compacted material to reduce the external slope to
1:2 or flatter; or
b) is retained by either a deepened reinforced concrete beam
which forms an integral part of the slab, or by a masonry
foundation wall in accordance with the requirements of
SANS 10400-B or SANS 10400-K, as relevant.
40
44. 4.3.2.1.6 The foundation may be stepped in conjunction with
the requirements of 4.3.2.1.5 in order to reduce the extent
of the excavation or fill, provided that at the change of
elevation, the ground behind any step is adequately drained
and the step waterproofed.
4.3.2.1.7 A competent person (civil engineering) shall design
and inspect the installation of subsurface drains that might
be required to prevent the passage of moisture into the
interior of the building footprint.
44
45. 4.3.2.2 Strip foundations on class C, H, R and S sites
4.3.2.2.1 Strip foundations for single-storey buildings on
class C, H, R and S sites shall
a) have a width as given in table 3,
b) be in accordance with figure 5, subject to the slab not
exceeding 200 m2 where the alternative detail using
thickened slabs is used, and
c) have a thickness of not less than 200 mm, except in the
case of bearing onto solid rock, where the thickness shall
be sufficient to achieve a level surface.
45
46. 4.3.2.2.2 Service trenches shall, as far as is practicable, not
be excavated parallel to buildings within 1 500 mm of the
building perimeter.
4.3.2.2.3 Steps in foundations greater than 400 mm shall be
designed in accordance with the requirements of 4.1.1(a).
46
49. 4.3.2.3 Slab-on-the-ground foundations on class C, H, R and S
sites
4.3.2.3.1 Slab-on-the-ground foundations for single-storey
buildings on class C, H, R and S sites shall be in accordance
with figure 6 where such foundations
a) have a surface area that does not exceed 200 m2,
b) are free of joints,
c) do not contain any changes in surface levels with steps
that exceed 400 mm, and
d) do not support any chimneys or walls which support
concrete roofs.
49
50. 4.3.2.3.2 Edge beams that have a depth greater than 750
mm and steps in the floor at any change in level of slab-on-
the-ground foundations in excess of 400 mm shall be
designed and constructed in accordance with the
requirements of 4.1.1(a).
4.3.2.3.3 Service trenches shall, as far as is practicable, not
be excavated parallel to buildings within 1 500 mm of the
building perimeter.
4.3.2.3.4 Steps in foundations greater than 400 mm shall be
designed in accordance with the requirements of 4.1.1(a).
50
52. 4.3.2.4 Modified normal construction on class C1, H1 and S1
sites
4.3.2.4.1 Modified normal construction for single-storey
buildings on class C1, H1 and S1 sites shall be in accordance
with table 4 and the relevant requirements of figures 7 to 10
where such buildings
a) contain no concrete roofs,
b) contain no arches, and
c) have lintels over openings in accordance with the
requirements of SANS 10400-K.
52
54. 4.3.2.4.2 Steps in foundations greater than 400 mm shall be
designed in accordance with the requirements of 4.1.1(a).
4.3.2.4.3 Apron slabs, where required, shall comprise
concrete slabs cast to falls, that have a width not less than
the greater of 1 000 mm and the roof overhang plus 600
mm. Such slabs shall either be 75 mm thick and be provided
with joints at centres that do not exceed 2,0 m, or be 100
mm thick and be centrally reinforced with fabric reinforcement
ref. 100.
4.3.2.4.4 Articulation joints shall be in accordance with the
requirements of SANS 10400-K.
54
59. 4.3.2.4.5 The interface at the extension between new and
existing buildings shall be in accordance with figure 11.
59
60. 4.4 Foundations for free-standing walls and retaining walls
Foundations for free-standing walls and retaining walls that
comply with the requirements of SANS 10400-K shall be in
accordance with figures 12 and 13, respectively.
60
65. Definitions
floor joist
horizontal beam which is the primary structural member in
the construction of a timber floor
flooring board
board of face side width not less than 50 mm and not more
than 140 mm, which may be tongued on the one edge and
grooved on the opposite edge
foundation
that part of a building which is in direct contact with, and is
intended to transmit loads to, the ground
65
66. foundation wall
that portion of a wall between the foundation and the
lowest floor above such foundation
load
value of a force corresponding to an action
sleeper wall
masonry wall constructed to support a suspended ground
floor
sole plate
strip of timber which is laid on top of walls to level the
underside of flooring joists
66
67. span
distance between the centres of supports
strip flooring
floor that comprises strips of width not less than 35 mm
and not more than 90 mm and that are tongued on the one
edge and grooved on the opposite edge
suspended floor
floor that spans supports
67
68. J1 GENERAL REQUIREMENT
1. Any floor of any building shall –
a) be designed and constructed to safely support its own
weight and any actions which can reasonably be
expected to occur and in such a manner that any local
damage ( including cracking ), deformation or vibration
do not compromise the efficient use of the building or
the functioning of equipment supported by such floor;
and
b) have a fire resistance appropriate to its use and where
required, be non-combustible.
68
69. 2. The floor of any laundry, kitchen, shower-room, bathroom
or room containing a toilet pan or urinal shall be water-
resistant.
3. Any suspended timber floor in a building shall be
provided with adequate under-floor ventilation.
4. Where any concrete floor slab is supported on ground or
filling, such floor shall be so constructed that any
moisture present in such ground or filling is prevented
from penetrating such concrete floor slab.
69
70. 5. The requirements of sub-regulations (1), (2), (3) and (4)
shall be deemed to be satisfied where the design and
construction of any floor complies with SANS 10400-J:
Provided that where the local authority deems it
necessary in order to satisfy the requirements of sub-
regulation (4), such local authority may require that the
entire area within the foundation walls of any building be
covered by a suitable damp-proof membrane, and in the
case of the floor of a basement or semi-basement where
the highest known level of the extreme watertable is
higher than the floor level of the basement to such an
extent that uplift of the floor might occur, the local
authority may require that adequate sub-soil drains under
the floor be provided together with means of removing
the water so drained. 70
72. 4 Requirements
4.1 General
The functional regulations contained in part J of the
National Building Regulations (see annex A) shall be
deemed to be satisfied where
a) floors in any laundry, kitchen, shower room,
bathroom or room containing a toilet pan or urinal
comply with the requirements of 4.2;
72
73. b) suspended floors are in accordance with the
requirements of one of the following:
1) SANS 10400-B and SANS 10400-T;
2) SANS 10082; or
3) 4.3 in the case of occupancies classified as E4, H3,
H4 and H5 (see Regulation A20 in SANS 10400-A) in
single-storey and double-storey buildings where floors
are not exposed to the elements;
73
74. c) slabs supported on the ground are in accordance
with the requirements of
1) SANS 10400-B,
2) SANS 10400-H, or
3) 4.4; and
74
75. d) all timber (see Regulation A13(b) used in the
erection of a building shall be preservative treated in
accordance with SANS 10005, as relevant.
75
76. 4.2 Water-resistant floors
A water-resistant floor shall
a) be constructed of concrete in accordance with the
requirements of SANS 2001-CC1 or SANS 2001-CC2; or
b) comprise an impervious material, fit for its intended
purpose, laid on top of, or bonded to, the flooring system,
which
1) can hold any surface water in such a manner that it
prevents the flooring system from deteriorating in any
way until such time that the water can evaporate, be
drained or be removed, and
2) can accommodate any movement in the flooring
system without losing its impermeable properties.
76
77. 4.3 Suspended timber floors not exposed to the
elements
4.3.1 Floor joists, which are either built into walls with
a minimum end bearing of 75 mm or bolted to walls
by means of joist hangers (see figures 1 and 2), shall
comply with the requirements of SANS 1460 or SANS
1783-2, shall be in accordance with the provisions of
table 1 or table 2, and shall comply with the
requirements of SANS 2001-CT1.
77
82. 4.3.2 Timber flooring shall be in accordance with the
provisions of table 3, shall comply with the requirements of
SANS 2001-CT1, and shall be fixed to floor joists at centres
that do not exceed 600 mm.
82
84. 4.3.3 The clearance between the under-surface of the
ground floor joists and the ground beneath shall be at
least 450 mm (see figure 1). Access to the space below
shall be provided for inspection purposes and shall be
fitted with covers or doors that prevent entry of rain,
termites (in their flying stage), reptiles and vermin. All
debris and the like shall be removed from the void
below such floors upon completion.
84
85. 4.3.4 Ventilation of the subfloor space in suspended
ground floors shall be provided by means of openings
spaced not more than 2,4 m apart with at least one
opening within 0,75 m of each corner. The total area of
ventilation openings provided shall be not less than
1000 mm2 of unobstructed air passage per square
metre of floor area. All ventilation openings shall be
fitted with corrosion resistant screening of nominal
aperture that does not exceed 1,2 mm.
NOTE A 0,220 m × 0,170 m airbrick has an
unobstructed area of between 0,006 m2 and 0,009 m2.
Accordingly, one such airbrick is required to serve
between 6 m2 and 9 m2 of flooring.
85
86. 4.3.5 Floor joists in suspended ground floors shall be
set on and skew-nailed to sole plates that have
minimum dimensions of 38 mm × 76 mm on top of
sleeper walls (see figure 2). Sleeper walls shall be
provided with sufficient openings to ensure good cross
ventilation.
NOTE At the junction of solid and suspended floors,
e.g. at verandahs, ventilation pipes might have to be
provided underneath solid concrete floors. Where
sleeper walls are used, ventilation openings of size at
least 115 mm × 75 mm spaced at 1,0 m centres
should be provided.
86
87. 4.3.6 Metal masonry anchors shall be of the expanding
type, be corrosion resistant, have a diameter and length
of not less than 10 mm and 45 mm, respectively, and
shall be installed in accordance with the manufacturer’s
instructions. Such anchors, when embedded in grade
20 concrete for standard test purposes, shall have a
safe working load in shear of not less than 2,5 kN,
certified by the manufacturer. Such certification shall be
substantiated by test report certificates from an
accredited testing laboratory.
87
88. 4.3.7 Metal punched plate hangers shall have a zinc
galvanized coating of not less than 275 g/m2 and shall
bear a mark which readily identifies the manufacturer or
supplier. Hangers shall be tested by an accredited
testing laboratory to demonstrate that, when bolted or
nailed through predrilled or prepunched holes into
structural softwood (pine) members, they can transfer a
permissible load of at least 4,0 kN across the joint
without slippage occurring.
4.3.8 No timber floor joist or trimmer or any other
combustible material shall be built into any hearth (see
4.4.3 of SANS 10400-V:2010), or within 200 mm of
the inside of a chimney (see 4.3.1(c) of SANS 10400-
V:2010), or penetrate a fire separation element. 88
89. 4.4 Floors supported on ground or filling
4.4.1 A floor supported on ground or filling and which
does not form an integral part of a foundation system,
does not pass over or is not supported on foundation
walls, shall
a) be designed and constructed in accordance with the
requirements of SANS 10109-1 under the direction of
a competent person (civil engineering); or
89
90. b) in the case of a building not used for storage or
industrial purposes, be constructed of
1) impervious floor units, not less than 40 mm thick,
consisting of slate, bricks, natural stone or other
suitable material; or
90
91. 2) a plain grade 10 concrete slab where the slab does
not serve as the final wearing surface, or a plain grade
15 concrete slab where the slab serves as the final
wearing surface, of thickness not less than 75 mm, laid
on a polyolefin underfloor membrane and constructed
in accordance with the requirements of SANS 2001-
CC1, provided that any panel dimension does not
exceed
• 3,5 m where floors are covered with carpets and
flexible floor covering, or
• 2,5 m where floors are covered with semi-flexible or
rigid tiles.
91
92. NOTE 1 Plain concrete panels that have a panel dimension
greater than 2,5 m and 3,5 m, depending upon the
proposed floor covering, fall outside the scope of 4.4.1(b)(2).
Such slabs should be designed by a competent person (civil
engineering) or be fabric-reinforced in accordance with the
requirements for slab-on-the-ground foundations contained in
SANS 10400-H to mitigate the effects of drying shrinkage.
NOTE 2 Plain concrete floors that comply with the
requirements of 4.4.1(b)(2) should perform in accordance
with the relevant requirements of SANS 10400-B. Fabric
reinforcement will be required to improve performance to a
lower category of expected damage (see SANS 10400-B).
Guidance in this regard is provided in SANS 10109-1.
92
93. 4.4.2 A floor supported on ground or filling shall comply
with the relevant requirements of SANS 10400-B or SANS
10400-H should it
a) form an integral part of a foundation system;
b) be constructed of plain concrete and have any panel
dimension exceeding 3,5 m; or
c) pass over or be supported on foundation walls.
4.4.3 Floors provided in terms of 4.4.1 and 4.4.2 shall be
constructed level or have a slope that does not exceed 4
mm/m.
93
94. 4.4.4 Polyolefin underfloor membranes shall have a
thickness of not less than 250 μm or be the subject of
an Agrément certificate and be provided where site
and ground conditions necessitate that the floor be
underlain with such membranes. Such membranes shall
be turned up around the perimeter of the floors by at
least the thickness of the floor and be provided with
an overlap of 200 mm at joints. Penetrations by pipes,
plumbing fittings or punctures shall be taped with a
pressure-sensitive adhesive tape approved for such
use by the manufacturer.
94
95. 4.4.5 Filling beneath floors constructed in accordance with
4.4.1(b) shall comprise material that
a) contains little or no organic material (material produced
by animal or plant activities);
b) excludes stones of average dimensions larger than 75
mm;
c) does not contain more than 10 % rock or hard
fragments of material retained on a sieve of nominal
aperture size 50 mm;
95
96. d) does not contain large clay lumps that do not break up
under the action of compaction, nor be a predominantly
clayey material; and
e) can be placed without significant voids.
96
97. 4.4.6 Filling shall be moistened before compaction so
that a handful squeezed in the hand is firm, but does
not show signs of moisture. Filling shall be placed in
uncompacted layers not exceeding 100 mm in respect
of hand compaction or 150 mm in respect of
compaction by mechanical means. Each layer shall be
well compacted before additional fill material is added.
4.4.7 A competent person (civil engineering) shall
design and inspect fills where the maximum height of
fill beneath floors, measured at any point, exceeds 400
mm.
97
