CD/SZNS 070:2022  
 
ICS 91.100.25                             Edition 1  
             
 
 
 
 
 
 
ESWATINI NATIONAL STANDARD  
 
 
 
 
 
 
CONCRETE ROOFING TILES  
 
 
 
 
 
 
 
 
 
 
Published by: Eswatini Standards Authority  
Marble Construction Building, Plot 247 11th Street King Mswati III Avenue West  
P. O. Box 1399, Matsapha, Kingdom of Eswatini  
Telephone: +268 2518 4633, Facsimile: +268 2518 4526  
Website: www.swas a.co.sz  
E-mail: info@swasa.co.sz   
©Eswatini Standards Authority 2019  
 
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 Table of changes  
Clause Changed  Date  Change  
   
 
NATIONAL FOREWORD  
This Eswatini National final draft Standard was prepared by Technical Committee SWASA/TC 30 Construction in 
accordance with procedures of the Eswatini Standards Authority, in compliance with Annex 3 of the WTO/TBT 
Agreement.  
Annexes B to D are for information only.  Amdt 1   
Table of changes  
Change No.   Date   Scope   
Amdt 1  2012  Amended to update referenced standards.  
Amdt 2  2015  Amended to correct the table on sample size for quality 
disputes.  
Amdt 3  2020  Amended to update referenced standards, the subclause on 
materials, and to delete the annex on notes to purchasers.  
 
 
 
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 Contents             Page  
 
 
 
 
 
 
 
  
 
 
 
 
 
 
 
 
 
 
Figures 1 to 7  .................................................................................................................. .............. ......  13 -18  
  
Annex A Deleted by amendment No. 3   
  
Annex B (informative) Surface characteristics ......................................................... .......... ...........   19  
  
Annex C (informative) Efflorescence ......................................................................... ......... ..........   20  
  
Annex D  (informative) Quality ve rification of concrete roofing tiles ............................... .............   21  
  
Bibliography  ............................................................................................................ ............ ............  22   
  Foreword  
   
1 Scope ............................................................................................................... ............ ........... ...   
  3  
2 Normative references  ..................................................................................................... ........ ..   
  3  
3 Definitions, symbols and abbreviations ........................................................................ ...........   
  4  
4 Requirements .......................................................................................................... ........ ..........   
  5  
5 Compliance and sampling .............................................................. ............................ ..............   
  8  
6 Test methods  ........................................................................................................... ...............   
  8  
7 Marking, labelling and packaging ............................................................................ ...............   11  SZNS 070:2022  
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  SZNS 070:2022  
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 Concrete Roofing Tiles  
1 Scope   
This standard specifies requirements for concrete roofing tiles, limited to those described in the text, for assembly into 
pitched roof coverings.  
 
2 Normative  references   
The following standards contain provisions which, through reference in this text, constitute provisions of this standard. 
All standards are subject to revision and, since any reference to a standard is deemed to be a reference to the latest 
edition of that  standard, parties to agreements based on this standard are encouraged to take steps to ensure the use of 
the most recent editions of the standards indicated below. Information on currently valid national and international 
standards can be obtained from th e South African Bureau of Standards.  
 
EN 12878, Pigments for the colouring of building materials based on cement and/or lime – Specifications and methods 
of test.  
SANS 1083, Aggregates from natural sources – Aggregates for concrete.   
SANS 1491 -1 (SABS 1491 -1), Portland cement extenders – Part 1: Ground granulated blastfurnace slag .  
 Amdt 1   
SANS 1491 -2 (SABS 1491 -2), Portland cement extenders – Part 2: Fly ash .  Amdt 1   
SANS 1491 -3 (SABS 1491 -3), Portland cement extenders – Part 3: Co ndensed silica fume . Amdt 1   
SANS 10100 -2, The structural use of concrete – Part 2: Materials and execution of work .  Amdt 3   
SANS 50197 -1/EN 197 -1, Cement – Part 1: Composition, specifications and conformity criteria for common cements.  
SANS 50413 -1/EN 413-1, Masonry cement – Part 1: Composition, specifications and conformity criteria.   
SANS 50450 -1/EN 450 -1, Fly ash for concrete – Part 1: Definition, specifications and conformity criteria. 
 Amdt 1   
SANS 50450 -2/EN 450 -2, Fly ash for concrete – Part 2: C onformity evaluation.  Amdt 1   
SANS 50934 -2/EN 934 -2, Admixtures for concrete, mortar and grout – Part 2: Concrete admixtures – 
Definitions, requirements, conformity, marking and labelling.  Amdt 3  SANS 50934 -6/EN 934-6, Admixtures 
for concrete, mortar and grout – Part 6: Sampling, conformity  
control and evaluation of conformity .   Amdt 3   
SANS 53263 -1/EN 13263 -1, Silica fume for concrete – Part 1: Definitions, requirements and conformity criteria.  
 Amdt 1   
SANS 53263 -2/EN 13263 -2, Silica fume for concrete – Part 2: Conformity evaluation.  Amdt 1   SZNS 070:2022  
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 SANS 55167 -1/EN 15167 -1, Ground granulated blast furnace slag for use in concrete, mortar and grout – Part 1: 
Definitions, specifications and conformity criteria.   Amdt 1   
SANS 55167 -2/EN 15167 -2, Ground granulated blast furnace slag for use in concrete, mortar and grout – Part 2: 
Conformity evaluation.   Amdt 1   
 
3 Definitions , symbols and abbreviations   
3.1 Definitions   
For the purposes of this standard, the following definitions apply.  
3.1.1 acceptable  
acceptable to the authority administering this standard or to the parties concluding the purchase contract, as relevant  
3.1.2 additive  
product which is added in small quantities in proportion to the mass of the cement before or during mixing or during 
an additional mixing operation, causing required modifications to the properties  
3.1.3 aggregate  
concrete component consisting of uncrushed or crushed natural substances  (or both) and artificial mineral substances 
with particle sizes and shapes suitable for the production of concrete  
3.1.4 average transverse strength  
average value of the transverse strengths of the individual tiles  
3.1.5 cement  
hydraulic binder, i.e. finely ground inorganic materials which when mixed with water, form a paste which sets, by 
means of hydration and which, after hardening, retains its strength and stability  
3.1.6 interlocking tile IL  
profiled or flat tile which has a side lock with or without a head lock feature  
3.1.7 irregular front edge IF  
edge of a tile (interlocking and non -interlocking) which, by design, has an irregular varying hanging length across 
the width  
3.1.8 non -interlocking tile NL  
generally flat, c ross cambered or longitudinally (or both) cambered tile, which is usually rectangular in shape, with 
or without a featured front edge  
3.1.9 pigment  
addition inert to the ingredients of concrete and intended to provide colour to the concrete  SZNS 070:2022  
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 3.1.10 quali ty control test  
test performed on samples drawn either from continuous production or from a consignment of finished products, to 
establish whether a batch of products conforms to this standard  
3.1.11 regular front edge RF  
edge of a tile (interlocking and non -interlocking) which, by design, has a constant or regularly varying hanging length 
across the width  
 
3.2 Symbols  and abbreviations   
Cw  
  nominal cover width of one tile  
Cwc  
  cover width closed up value of ten tiles  
Cwd  
  cover width drawn out value of ten tiles  
d  
  profile depth of a tile (see figure 4)  
Fa  
  average transverse strength of tiles  
Fi   transverse strength of an individual tile  
IF  
  irregular front edge  
IL  
  interlocking  
L1  
  hanging length of a tile (see figure 1)  
L2, L3   
  hanging edge length (see figure 1)  
NL  
  non-interlocking  
RF  regular front edge  
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 4 Requirements   
4.1 Materials   
4.1.1  Cementations  binder   Amdt  3  
Common cement that complies with the requirements of SANS 50197 -1 or blends of certain types of common cement 
and cement extenders that comply with the requirements of SANS 55167 -1, SANS 50450 -1, SANS 50450 -2, SANS 
50934 -6, SANS 53263 -1, SANS 53263 -2, or SANS 50934 -2.  Amdt 3   
4.1.2 Extenders   
Extenders used shall comply with the relevant requirements of SANS 10100 -2. Amdt 1; amdt 3   
4.1.3 Pigments   
Pigments used shall comply with the requirements of EN 12878 (see annexes A and B).  
4.1.4 Aggregate   
Aggregates used shall consists of natural sand or crushed or uncrushed gravel, stone or rock or any combination of 
these, that complies with the relevant requirements of SANS 1083.  Amdt 3   
4.1.5 Water   
Water used in the mixing of concrete shall comply wit h the requirements of SANS 10100 -2. Amdt 3  
NOTE   For information on efflorescence see annex C.  
 
4.2 Hanging  length and squareness   
The tile hanging length shall be declared in the manufacturer’s technical specification. For tiles with a regular front 
edge, the values of L1 shall be within ± 4 mm of the manufacturer’s declared value when tested according to 6.1.  
The squareness for tiles with a nominally constant hanging length, when tested in accordance with 6.1, shall be 
calculated as the difference between values L2 and L3, and shall be not greater than 4 mm.  
NOTE   Some tiles are designed, for example for aest hetic reasons, with an irregular front edge (IF). In these cases, the test method and 
requirements do not apply.  
 
4.3 Cover  width   
4.3.1 General   
The stated cover width Cw shall be declared in the manufacturer’s technical specification.  
NOTE   Some tiles are designed, for example for aesthetic reasons, with a random cover width. In these cases, the requirement s specified in 4.3 
do not apply.  SZNS 070:2022  
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 4.3.2 Interlocking  tiles  
When tiles are tested in accordance with 6.2.1, the average cover width  shall be within ± 5 mm of the manufacturer’s 
declared value.  
4.3.3 Non -interlocking tiles   
 When tiles are tested in accordance with 6.2.2, the average cover width shall be within ± 3 mm of the manufacturer’s 
declared value.  
 
4.4 Flatness   
 When tiles a re tested in accordance with 6.3, the gap between any desired contact point and the flat surface shall not 
exceed 3 mm.  
NOTE   For some tile patterns, the test method and the requirements in 4.4 are not suitable and do not apply, for example:  
a) the tiles are designed to have less than four desired contact points to a flat surface; or  
b) the tiles are designed to be irregular, for example, for aesthetic reasons.  
 
4.5 Mass   
The mass of tiles shall be declared in the manufacturer’s technical specific ation.  
When tiles are tested in accordance with 6.4, the average mass shall be:  
a) manufacturer’s declared mass ± 0,2 kg for tiles with a declared mass not exceeding 2 kg; and  
b) manufacturer’s declared mass ± 10 % for tiles with a declared mass greater than 2 kg.  
 
4.6 Fixing  holes (where provided)   
Fixing holes shall be of an acceptable diameter and shall be positioned within 14 mm to 20 mm of the batten lug(s).  
Plain tiles shall have two fixing holes, the centre of each hole being not less than 25 mm and n ot more than 45 mm 
from the adjacent side of the tile.  
Profiled interlocking tiles shall have at least one fixing hole that is as close as practicable to the longitudinal centre 
line of the tile.  
NOTE   It is important that fixing holes be arranged so that a permanent connection between the tiles and the batten can be a chieved.  
 
4.7 Transverse  strength   
When tiles are tested in accordance with 6.5, ( Fa) and (Fi) per millimetre of tile width  shall be not less than the 
appropriate value given in table 1.  
 
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 Table 1 — Minimum transverse strength per millimetre of tile width  
1  2 3   4 
 Interlocki ng tiles N   
Profiled    Flat  
Average  
Fa Individual  
Fi Average  
Fa   Individual  
Fi 
5,00 4,50 4,00   3,50 
  
4.8 Rain  penetration (impermeability)   
When tiles are tested in accordance with 6.6, drops of water shall not have formed on the underside of the roof tiles 
(dampness is permitted).  
NOTE   For information on efflorescence see annex C.  
 
5 Compliance  and sampling   
5.1 Concrete  roof tiles are deemed to comply with this standard when the manufacturer can demonstrate that a random 
sample taken from a production batch in accordance with table 2 satisfies each quality control test requirement.   
If a differ ent quality control system is used, it shall be agreed upon (see annex D).  
Table 2 — Sample size for quality control purposes  
1 2 3 4 5 
Test Requirement 
clause  Test 
method 
clause  Batc h size  
< 10 000  > 10 000  
Hanging length and 
squareness  4.2 6.1 3 5 
Cover widtha 4.3 6.2 ≥ 8 ≥ 8 
Flatness  4.4 6.3 3 5 
Mass  4.5 6.4 3 5 
Transverse strength  4.7 6.5 3 5 SZNS 070:2022  
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 Rain penetration  4.8 6.6 16 16 
a This test is only performed when requested.    
   
5.2 If the results of tests undertaken on the first sample are inconclusive, a second sample shall be taken in 
accordance with table 3, and shall comply with the acceptance criteria given in column 3 of the table.   
Table 3 — Sample size for quality disputes  
1 2 3 
Batch size  Sample size  Acceptance  
(maximum number of 
failures)  
< 151  
151 – 3 200  
3 201 – 35 000  
35 001 – 500 000  
> 500 001  3 
13 
20 
32 
50 0 
1 
2 
3 
5 
Amdt 2  
6 Test  methods   
6.1 Hanging  length and squareness of regular front edge (RF) tiles   
Hang the tile at an angle of 20° to 70° on a steel batten (see figure 1(a)). After having removed any burrs or other 
irregularities (or both), measure the distance from the top face of the batten to the lower front edge of the tile at the 
sides (see figure  1(b)). Record the values L2 and L3 to the nearest millimetre and calculate the value of L1 to the nearest 
millimetre.  
6.2 Cover  width   
6.2.1 Interlocking  tiles (IL)   
Hang or lay a minimum of ten tiles of the same nominal cover width with their locks fitting well, in the manner 
specified by the manufacturer.  
Push the tiles together to their minimum coverage, taking care that the interlocking parts of the tiles do not l ift or 
disengage. Measure to the nearest millimetre and record the closed up value Cwc (see figure 2(a)).  
Pull the tiles apart to their maximum coverage, taking care that the interlocking parts of the tiles do not lift or disengage . 
Measure to the nearest millimetre and record the drawn -out value Cwd (see figure 2(b)).  SZNS 070:2022  
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Calculate the average cover width to th e nearest 0,1 mm as follows:  
 
where  
n is the number of tiles used.  
6.2.2 Non -interlocking tiles (NL)   
Hang or lay a minimum of ten tiles of the same nominal cover width on a batten in the manner specified by the 
manufacturer.  
Push the tiles together. Measure, to the nearest millimetre, and record the width of the tiles. Calculate to 0,1 mm the 
average cover width.  
6.3 Flatness   
Place the tile on a flat level surface with the nibs projecting, as shown in figure 3. Hold the tile  down to ensure that the 
head of the tile is in contact with the surface.  
Use a steel bar with a diameter of 3 mm or Cw/100 mm, to the nearest millimetre, whichever is the greater. Check 
whether any gap between the lower front edge of the tile and the mea suring surface at any nominal contact point 
without lifting the tile, is greater than the specified value.  
Record the results for each tile tested.  
6.4 Mass   
Condition the tiles to be tested in their dry state at ambient temperature.  
Weigh each tile to at least the nearest 25 g. Record the values measured and calculate the average mass of the tiles in 
the sample to the nearest 10 g.  
 
6.5 Transverse  strength   
6.5.1 Conditions  of tiles   
Store the tiles to be tested at ambient temperature for at least 24 h in such a manner that air is free to circulate around 
all sides of each tile.  
 
6.5.2 Apparatus   
An apparatus that consists essentially of two supports in the form of self -aligning steel  bearers (of diameter 40 mm 
and whose distance apart is adjustable) and another steel bearer (of diameter 40 mm), through which the load is applied 
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 by suitable means at mid -span, along a line parallel to the supports. The length of each bearer exceeds the maximum 
width of the tile to be tested.  
6.5.3 Procedure    
6.5.3.1 Measurement  of profile depth, d  
If the manufacturer’s declared value of d is less than 20 mm, measure d for each tile in the sample, and calculate the 
average value for the sample (see figure 4).  
6.5.3.2 Positioning  the tile in the machine   
Place the tile to be tested with the top surface uppermost on the lower bearers of the test machine so that the centre 
line of the hanging length is midway between the two lower bearers (see figure 5). If the tile is not stable in this position 
(e.g. the tile rests in or on a water -lock), move the tile in the direction that brings the tile hanging nibs nearer to the 
bearer by  a distance specified by the manufacturer to ensure stable bearing.  
The angle of the upper bearer (loading bearer), in relation to the fixed lower bearer, does not exceed 10°. Use packing 
pieces with a flat top, as necessary, to achieve this (see figure 6 ). The width of the packing pieces does not exceed the 
diameter of the rounded part of the lower bearers.  
With plain and flat tiles, place an elastomeric pad between the upper bearer and the tile (see figure 5).  
With profiled tiles, arrange a contoured p acking block between the upper bearer and the tile (see figure 5). Use the 
contoured packing block made of hardwood or metal or moulded with plaster, which is 20 mm ± 1 mm wide. Where 
the contoured packing block is made of hardwood or metal, place an elast omeric pad between the contoured packing 
piece and the tile.  
The length of the elastomeric pad is at least equal to the width of the tile and is not less than 20 mm wide and 10 mm 
± 5 mm thick with a hardness of (50 ± 10) Shore A.  
So place the tile that the underlock (if applicable) is not loaded and in such a way that the load can be applied 
centrally on the cover width (see figure 6).   
NOTE   For quality control purposes, the test may be carried out without the use of the elastomeric pad and contoured p acking block.  
6.5.3.3 Load  application   
Apply the load through the upper bearer at a rate not exceeding 6 500 N/min until failure occurs.  
6.5.4 Recording  of test results   
Record the maximum load of each tile to the nearest 10 N. When calculating the total load, include the weight of 
the packing pieces used on the top surface if they exceed 5 N.  
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 6.6 Rain  penetration (impermeability)   
6.6.1 Apparatus   
a) The apparatus consists  of a rain penetration test rig (see figure 7) that simulates rainfall on the tiles. The test 
rig consists essentially of a section of a roof frame constructed at a pitch of 30° and of sufficient area to allow the test 
specimens (see 6.6.2) to be mounted o n it.  
The sides and back of the rig are enclosed and if the rig is used in the open, some form of  cover is needed to protect 
the roof from wind and rain. Access to the underside of the roof is provided for the purpose of observation. If 
necessary, illumination should also be provided.  
A sparge pipe is placed over the top of the roof frame to simulate the rain that would run down fr om higher courses 
of a full size roof. To simulate direct rainfall, a suitable spray or set of sprays is so placed over the area of the frame 
that every tile receives an equal volume of water. The flow is monitored by means of flow meters. The simulated 
rainfall used for the test is 150 mm/h from the sparge pipe and 75 mm/h from the spray. The flow rate required from 
the spray to achieve the simulated rainfall for a given roof area is calculated as follows:  
   Q = 1,25 × A  
  where  
  Q is the flow rate, in litres per minute (L/min);  
  A is the actual roof area, in square metres (m2).  
The flow rate from the sparge pipe is double that from the spray.  
b) A tank having a capacity of at least 100 L.  
c) A suitable pump, capable of delivering th e required flow rates.  
6.6.2 Test  specimens   
Take 16 tiles from the sample. Ensure that the tiles are not damaged in any way.  
6.6.3 Procedure   
In the case of interlocking tiles, lay the tiles on the test rig in a 4 × 4 arrangement with a head lap of 75 mm. In the 
case of plain tiles, lay the tiles in a similar arrangement but with a head lap of 65 mm. Start the flow of water and 
ensure that the r equired flow rate is achieved. Stop the flow after 2 h and inspect the underside of the tiles.  
 
7 Marking , labelling and packaging   
7.1 Products   
Concrete roof tiles complying with this standard shall be marked with the name of the manufacturer or trademark 
or with other means of identification.  
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 7.2 Documents   
The following particulars shall be indicated clearly on the delivery note or invoice or  supplier's certificate, supplied 
with the consignment of concrete roof tiles:  
a) the name or trademark or other means of identification of the manufacturer;   
b) the number of this standard if the tiles comply; and   
c) the name and colour of the product.   
 
(a) 
  
 
(b) 
  
Figure 1 — Hanging length and squareness of regular front edge (RF) tiles  
  
  
  
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(a) 
  
 
 
  
(b) 
  
Figure 2 — Cover width  
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Figure 3 — Flatness  
 
Figure 4 — Measurement of profile depth  
 
Figure 5 — Positioning of flat tile in the machine  
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Figure 6 — Testing with contoured packing blocks  
  
  
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Figure 7 — Permeability test rig  (simulated rainfall test)  
  
 
 
  
  
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 Annex A  
Deleted by amendment No. 3.  
Annex B  
(informative)  
Surface characteristics  
The shape of tiles should be flat or profiled and will be of one of the categories given in table B.1. The actual colour 
and surface coating should be as agreed upon.  
Table B.1 — Categories of concrete roofing tiles  
1 2 3 
Category  Body colour  Surface coating  
1 
2 
3 
4 No 
No 
Yes 
Yes No 
Yes 
No 
Yes 
  
Any surface coating applied to a tile should not contain material that is deleterious to the materials of which the tile 
is made. The tiles should be acceptably free from surface defects.  
The exposed surface of the tiles should have a structure which gives a harmonious appearance to the finished roof. 
However, slight colour variations in single colour tiles may occur as a result of the production process.  
Superficial, non -continuous cracks  may occur on the unexposed surfaces of the tile, resulting from the method of 
production. Scratches and abrasions caused by packaging, loading and transportation, are permissible provided they 
do not prejudice the other quality requirements.  
Changes in c olour and appearance will occur under the influence of natural weathering.  
 
 
 
 
 
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 Annex C  
(informative)  
Efflorescence  
C.1 General   
Efflorescence is a general term for the white deposits that form on concrete products. It is commonly known as lime 
and is more noticeable on dark roofing tiles because of optical contrast. It appears on the surface of the tile, either 
as white patches or as an overall lightening in colour, which is often mistakenly interpreted as colour being washed 
out of the tile.  
C.2 Cause   
Efflorescence results mainly from chemical changes that take place during the hydration period. During this process, 
the free lime  in the cement (in the form of calcium hydroxide) is liberated and migrates to the surface of the tile 
where it reacts with carbon dioxide in the atmosphere to form a white deposit of calcium carbonate.  
C.3 Duration   
The amount and duration of efflorescen ce depend on the chemical reaction in the cement and also on the prevailing 
weather and atmospheric conditions. The occurrence of cold winds and a sharp drop in temperature tend to increase 
the appearance of efflorescence. Efflorescence can develop as long  as the hydration of the cement continues but 
will usually stop after about two years. Rain and wind gradually remove the deposit, so that the true colour of the 
tiles is eventually restored.  
C.4 Conclusion   
The appearance of calcium carbonate efflorescen ce on a tile surface can take place in a number of different ways 
and there is at present no single method of preventing all such forms of efflorescence. It is also not possible to 
prevent efflorescence by the addition of an additive because such an additi ve would have to cover a broad range of 
variables during the process. Efflorescence is purely superficial and does not affect the durability of the tile, the 
strength of the concrete, the original colour or the functional properties of the tile.  
 
 
 
 
 
 
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 Annex D  
(informative)  
Quality verification of concrete roofing tiles  
D.1 When  a purchaser/authority requires ongoing verification of the quality of the roofing tiles, it is suggested that, 
instead of concentrating solely on evaluation of the final product, he also direct his attention to the manufacturer’s 
quality system. In this c onnection it should be noted that SANS 9001 covers the provision of an integrated quality 
system.   
D.2 If no information about the implementation of quality control or testing during manufacture is available to help 
in assessing the quality of a consignmen t, and a purchaser/authority wishes to establish by inspection and testing of 
samples of the final product, whether a consignment of the product complies with this standard, a sampling plan 
based on applicable statistical principles should be agreed upon b etween the supplier and the purchaser/authority.   
It should be noted that :  
a) such a sampling plan  applies only to ready -for-use products sampled in accordance with an agreed 
procedure, and  
b) if another sampling plan is to be used, a clear statement should be  made as to the objective of the sampling 
as described in the method.  
Recommended sample sizes for the inspection and testing of concrete roofing tiles are given in table 2.  
  
 
 
 
 
 
 
 
 
 
 
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 Bibliography  
SANS 9001/ISO 9001, Quality management systems – Requirements.   
SANS 10062, Fixing of concrete interlocking roofing tiles.