quantities for ordering

building materials
1. introduction
The quantities given in this pamphlet are approximate. They • The importance of curing cannot be overemphasised.
form a basis for a first estimate of quantities to be used on site. For hardening to occur, cement must have access to water.
Once the concrete is allowed to dry, no further strength
The following notes apply generally. development will take place. Preventing excessive loss
of water is also important to avoid cracking and crazing
• Mix proportions in the tables are based on materials being and the possibility of a weak dusty surface. Cure for at
batched in a loose state, i.e. poured into the batching least 7 days, and longer in cold weather when strength
container without being compacted development slows down.

• “Common cement” complies with SANS 50197-1. “Masonry

cement” complies with SANS 50413-1 strength class 22,5X. 2. materials quantities for concrete
The volume of concrete, for rectangular shapes
• A bag of cement contains 50 kg of cement. such as foundation strips, floor slabs, etc, is:
thickness x length x breadth.
• It is recommended that cement is only batched in
whole bags. If each of these dimensions is measured in metres, the
volume will be in cubic metres.
• The capacity of a builder’s type 5 wheelbarrow
com­plying with SANS 795 is about 65 l. Volumes of 130 l Quantities of materials for concrete suitable for hand
and 200 l are therefore equivalent to two and three compaction (i.e. without the use of poker vibrators) are shown
barrowsful respectively. in Tables 1a-d and do not include allowance for wastage.

• The selection of good quality sand and stone is important.

• Only sufficient water should be used to produce a workable

mix of 60-100 mm slump. Too much mixing water will
reduce the strength of the concrete.

Table 1a: 32,5N or R Common cement, 19 mm stone

Strength Material quantities for 2-bag mixes Quantities per m3 of concrete
at Cement Sand Stone Yield Cement Sand Stone
28 days 50 kg bags m 50 kg bag m m3
Wheelbarrows / Litres 3

LOW 3,5 3,5

2 0,35 5,8 0,65 0,65
15 MPa 230 l 230 l
MEDIUM 2,5 2,5
2 0,26 7,7 0,62 0,62
25 MPa 160 l 160 l
HIGH 2,0 2,0
2 0,22 9,2 0,60 0,60
30 MPa 130 l 130 l
Table 1b: 32,5N or R Common cement, 13,2 mm stone

Strength Material quantities for 2-bag mixes Quantities per m3 of concrete
at Cement Sand Stone Yield Cement Sand Stone
28 days 50 kg bags m3 50 kg bag m m3
Wheelbarrows / Litres 3

LOW 4,0 32,5

2 0,33 6,1 0,80 0,50
15 MPa 260 l 160 l
MEDIUM 2,5 2,0
2 0,24 8,4 0,68 0,54
25 MPa 160 l 130 l
HIGH 2,0 1,5
2 0,20 10,2 0,66 0,50
30 MPa 130 l 100 l

Table 1c: 42,5N or R Common cement, 19 mm stone

Strength Material quantities for 2-bag mixes Quantities per m3 of concrete
at Cement Sand Stone Yield Cement Sand Stone
28 days 50 kg bags m3 50 kg bag m3 m3
Wheelbarrows / Litres
LOW 4,0 4,0
2 0,39 5,1 0,67 0,67
15 MPa 260 l 160 l
MEDIUM 3,0 3,0
2 0,30 6,6 0,64 0,64
25 MPa 200 l 200 l
HIGH 2,5 2,5
2 0,26 7,8 0,62 0,62
30 MPa 160 l 160 l

Table 1d: 42,5N or R Common cement, 13,2 mm stone

Strength Material quantities for 2-bag mixes Quantities per m3 of concrete
at Cement Sand Stone Yield Cement Sand Stone
28 days 50 kg bags m3 50 kg bag m3 m3
Wheelbarrows / Litres
LOW 4,5 3,0
2 0,37 5,4 0,79 0,53
15 MPa 300 l 200 l
MEDIUM 3,0 2,5
2 0,28 7,1 0,69 0,58
25 MPa 200 l 160 l
HIGH 2,5 2,0
2 0,24 8,4 0,67 0,55
30 MPa 160 l 130 l

Notes on mixes in Tables 1a – 1d:

1. Low-strength (15 MPa) concrete is suitable for unrein­forced foundations (single storey only); mass fill, infill concrete in masonry
(only with13,2 mm stone).

2. Medium-strength (25 MPa) concrete is suitable for un­rein­­forced slabs, reinforced slabs and foundations, infill concrete in masonry
(only with 13,2 mm stone).

3. High-strength (30 MPa) concrete is suitable for rein­forced concrete members and precast items such as concrete flagstones.

3. mortar mix proportions

The proportion of each material in the mix should suit the Class ll
type of work being done. Strength requirements and mix Normal loadbearing applications, as well as parapets,
proportions recommended by C&CI are given in Table 2. balus­trades, retaining structures, and freestanding and garden
walls, and other walls exposed to possible severe dampness.
In general, the classes of mortars may be used as follows: In practice, Class II mortars are used for most applications.
Although SANS 10249 refers to a Class III mortar, it is so seldom
Class l used that it has been omitted from Table 2.
Highly stressed masonry incorporating high-strength structural
units such as might be used in multi-storey loadbearing Other proportions may be used if these can be shown by
buildings. Reinforced masonry. test to be satisfactory.
Table 2: Mortar strength requirements and mix proportions
Minimum required Quantity of sand1 Quantities of materials required
compressive strength per 50 kg bag per m3 of mortar
at 28 days, MPa of cement, l (not including wastage)
Mortar
class Preliminary Common2 Masonry3 Common2 Masonry3
Works Sand Sand

laboratory cement cement cement, bags 3 cement, bags
tests m m3
tests 32,5, 42,5 22,5X 32,5, 42,5 22,5X
I 14,5 10 130 l 65 l 9,5 1,23 14,5 1,07

II 7 5 200 l 130 l 7,0 1,34 9,5 1,23

1. Sand is estimated at a 5% moisture content.

2. Common cement complying with SANS 50197-1, strength class 32,5 or 42,5.
3. Masonry cement complying with SANS 50413 -1, strength class 22,5X.

NOTE: The addition of lime is optional. A maximum of 40 l is permitted per 50 kg of Common cement.
Mix proportions do not need to be adjusted. Only yield will increase by 5%.
Do NOT use lime with masonry cement.

Table 3: Quantities of masonry units and mortar

3
4. quantities of masonry units and mortar Masonry unit size, mm Masonry Mortar m per
units2 1 000 100 m2
The dimensions of units given in Table 3 are those of the
Length Width
Height
per m
commonly manufactured sizes. units walling

190 90 90 50 0,27 1,35

Notes:
• The table is based on exact sizes of solid masonry units, 190 190 90 50 0,57 2,85
with 10 mm thick bedding and vertical joints, and no
wastage. For 15 mm thick joints, multiply the quantity of 222 90 73 52 0,29 1.51
mortar required by 1,5; for 20 mm thick joints, multiply by 2.
222 106 73 52 0,34 1,77

• Since no allowance is made for a number of factors 290 90 90 34 0,36 1,21

which could influence mortar quantities, the following
adjustments should be made: 290 90 140 23 0,41 0,92

290 140 90 34 0,56 1,87

1. Allow for wastage which could typically range from
20 % to 200 %. 290 140 140 23 0,63 1,41

2. For hollow units reduce mortar quantities by: 390 90 90 25 0,45 1,13
Width of units, mm % reduction
390 90 190 13 0,54 0.68
90 - 110 mm 20
140 mm 30 390 140 90 25 0,70 1,75
190 - 220 mm 40
390 140 140 17 0,77 1,29
3. For units with perforations or holes increase mortar
390 140 190 13 0,84 1,05
quantities by 15%.
390 190 90 25 0,95 2,38
4. For units with frogs; frog laid face up (as required for
structural walls), increase mortar quantities by 15%. 390 190 190 13 1,14 1,43

5. Once the above adjustments have been made: 440 90 190 12 0,59 0,67
for mortar ready-mixed and delivered into watertight
440 140 190 12 0,90 1,01
containers on site, reduce quantities by 20% as
against site-mixed mortars 440 190 190 10 1,24 1,37

6. For under- or oversized units: 440 110 220 10 0,75 0,75

Measure dimensions of 10 units and use the
440 220 220 10 1,50 1,50
average for calculating the number of units per m2.
5. materials for plaster
Quantities depend on the mix proportions, thickness of plaster and roughness of the background surface.

1 2 3
Exposure Common Sand Yield per Masonry Sand Yield per
conditions cement, kg l batch, l cement, kg l batch, l

External plaster 50 150 120 50 130 108

Internal plaster 50 200 150 50 150 120

1. Complying with SANS 50197-1, strength class 32,5 or 42,5

2. Sand is estimated at a 5% moisture content
3. Complying with SANS 50413-1, strength class 22,5X or 12,5

NOTE: The addition of lime is optional. A maximum of 40 l is permitted per 50 kg of Common cement.
Mix proportions do not need to be adjusted. Only yield will increase by 5%.
Do NOT use lime with masonry cement.

To calculate the approximate area that can be covered by appendix

a batch of plaster, use the following example: Field test for quality of sand for mortar and plaster.
Common cement using a 1:6 mix, This simple field test can be used to confirm that the sand yields
i.e. 50 kg cement to 200 l sand. a smooth, plastic and cohesive mix which does not require
From the table above, the yield = 150 l excessive amounts of water to reach a brick-laying or plastering
For 15 mm plaster thickness and 20% wastage consistence.
= 150 ÷ 15 ÷ 1,2
= 8,3 m2 Where possible, the test should be carried out on a sample of
sand before placing a final order.
6. materials for sand-cement floor screeds
Sand-cement screeds are essentially light-duty flooring The quantities used should be weighed out on a scale which is
elements and are suitable for: in good order, and the test carried out on a smooth impervious
surface. It is also important that the sample used is fairly
• Wearing surfaces of floors of utility rooms in domestic representative of the bulk supply.
premises (eg store rooms, garages)
Procedure
• Floors covered with carpets, plastic tiles or linoleum, etc i) Weigh out the following amounts of material:
and subjected to relatively light traffic such as in offices, 5 kg cement
shops and hospitals. 25 kg of dry sand
5 kg (l) of water
Sand-cement screeds are not suitable for industrial 1 kg (l) of water
premises.
ii) Mix the cement and sand to a uniform colour on a
Quantities of materials depend on the thickness of the screed. non-absorbent surface.
Using a mix consisting of 1 bag of cement and 130 l of coarse
sand, and assuming a screed thickness of 25 mm, quantities for iii) Mix, in succession, each of the amounts of water
2 3
100 m of screed are 23 bags of cement and 3,0 m of sand. (5 l and 1 l)

If 5 l is enough, the sand is of good quality

The suggested wastage factor is 10%.
If 5 l +1 l is enough, the mix is of average quality

Only “good” sands are recommended for exterior plasters.

“Average” sands may be used for interior plaster and mortar.

cement & concrete institute

po box 168, halfway house, 1685
block d, lone creek, waterfall park, bekker road, midrand
tel 011 315 0300 • fax 011 315 0584 • e-mail info@cnci.org.za • website http://www.cnci.org.za
published by the cement & concrete institute, midrand, 2009.
© cement & concrete institute