UGANDA STANDARD  
  DUS 816  
Second  Edition  
2019 -03-05 
 
 
 Reference number  
WDUS 816 : 2019 
© UNBS 2019   
  
Clay roofing tiles and ridges  — specification  
 DUS 816: 2019  
ii © UNBS 2019  – All rights reserved  
 Compliance with this standard does not, of itself confer immunity from legal obligations  
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible for its co rrect application  
© UNBS yyyy  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, including photocopying and microfilm, without prior written 
permission from UNBS.  
Requests for permission to reproduce this document should be addressed to  
The Executive Director  
Uganda National Bureau of Standards  
P.O. Box 6329  
Kampala  
Uganda  
Tel: +256 41 4 333 2 50/1/2/3  
Fax: +256 41 4 286 123  
E-mail: info@unbs.go.ug  
Web: www.unbs.go.ug  DUS 816:2018  
© UNBS 2019  – All rights reserved  iii 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ .............................  v 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4 Manu facture  ................................ ................................ ................................ ................................ ...........  2 
5 Physical requirements  ................................ ................................ ................................ ..........................  2 
5.1 Appearance  ................................ ................................ ................................ ................................ ............  2 
5.2 Shape  ................................ ................................ ................................ ................................ ......................  2 
5.2.1  Tile................................ ................................ ................................ ................................ ...........................  2 
5.2.2  Ridge  ................................ ................................ ................................ ................................ .......................  5 
5.3 Lugs (for Mangalore and Marseille tiles) ................................ ................................ .............................  6 
5.3.1  Batten lug  ................................ ................................ ................................ ................................ ...............  6 
5.3.2  Eaves lugs  ................................ ................................ ................................ ................................ ..............  6 
5.4 Corrugations and cross ribs  ................................ ................................ ................................ ................  6 
5.5 Water absorption and breaking load  ................................ ................................ ................................ ... 6 
5.6 Dimensions and  tolerances  ................................ ................................ ................................ ..................  6 
6 Performance requirements  ................................ ................................ ................................ ...................  7 
6.1 Weight  ................................ ................................ ................................ ................................ .....................  7 
6.2 Methods of test  ................................ ................................ ................................ ................................ ...... 7 
6.2.1  Water absorption  ................................ ................................ ................................ ................................ ... 7 
6.2.2  Permeability  ................................ ................................ ................................ ................................ ...........  7 
6.2.3  Breaking load  ................................ ................................ ................................ ................................ .........  7 
7 Marking  ................................ ................................ ................................ ................................ ...................  7 
8 Sampling and compliance with specification  ................................ ................................ .....................  7 
9 Inspection  ................................ ................................ ................................ ................................ ...............  8 
9.1 Appearance and marking  ................................ ................................ ................................ .....................  8 
9.2 Shape and dimensions  ................................ ................................ ................................ .........................  8 
Annex  A (normative)  Water abso rption test  ................................ ................................ ................................ ... 9 
A.1 Test specimen  ................................ ................................ ................................ ................................ ........  9 
A.2 Procedure  ................................ ................................ ................................ ................................ ...............  9 
A.3 Results  ................................ ................................ ................................ ................................ ....................  9 
Annex  B (Normative)  Permeability test  ................................ ................................ ................................ .........  10 
B.1 Test specimen  ................................ ................................ ................................ ................................ ...... 10 
B.2 Apparatus  ................................ ................................ ................................ ................................ .............  10 
B.3 Procedure  ................................ ................................ ................................ ................................ .............  10 
Annex  C (Normative)  Determination of break ing load (for Mangalore and Marseille tiles)  .....................  11 
C.1 Test specimen  ................................ ................................ ................................ ................................ ...... 11 
C.2 Apparatus  ................................ ................................ ................................ ................................ .............  11 
C.3 Procedure  ................................ ................................ ................................ ................................ .............  11 
C.4 Results  ................................ ................................ ................................ ................................ ..................  11 
Annex  D (Normative)  Determination of breaking load (for Roman and Portuguese tiles)  ......................  12 
D.1 Test specimen  ................................ ................................ ................................ ................................ ...... 12 
D.2 Apparatus  ................................ ................................ ................................ ................................ .............  12 
D.3 Procedure  ................................ ................................ ................................ ................................ .............  12 
D.4 Results  ................................ ................................ ................................ ................................ ..................  12 DUS 816: 2019  
iv © UNBS 2019  – All rights reserved  
 Bibliography  ................................ ................................ ................................ ................................ .....................  15 
 DUS 816:2018  
© UNBS 2019  – All rights reserved  v 
 Foreword  
Uganda Nat ional Bureau of Standards (UNBS) is a parastatal under the Ministry of Trade , Industry and 
Cooperatives established under Cap 327 , of the Laws of Uganda , as amended .  UNBS is mandated to co -
ordinate the elaboration of standards and is  
(a) a member of Internat ional Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex Alimentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT  Agreement  of the World Trade Organisation (WTO).  
The work of preparing Uganda Standard s is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a given field or area and consists of key stakeholders 
including government, academia, consumer groups, private sector and other interested pa rties.  
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda S tandards by the National Standards Council.  
The committee responsible for this document is Technical Committee UNBS /TC 03, Building and 
Construction . 
This second  edition cancels and replaces the first edition ( US 816:2008 ), which has been technically revis ed.  
 
 
 UGANDA STA NDARD  DUS 816: 2018  
 
© UNBS 2019  – All rights reserved  1 
 
 Clay roofing tiles and ridges  — Specification  
1 Scope   
This standard specifies requirements for  roofing  tiles and ridges intended for use as roof covering where 
durability and appearance are required to provide a weather -resistant surface of spe cified design.   
2 Normative references   
There are no normative references in this document . 
3 Terms and definitions  
For the purposes of this document, the following terms and definitions apply.  
ISO and IEC maintain terminological databases for use in sta ndardization at the following addresses:  
— ISO Online browsing platform: available at http://www.iso.org/obp  
3.1  
clay  
earthy or stony mineral aggregate consisting essentially of hydrous silicate of alumina; plastic when sufficiently 
pulverized and wette d; rigid when dry; and vitreous when fired to a sufficiently high temperature  
3.2  
clay roofing tile  
solid unit of clay formed into any of a range of generally rectangular planar shapes while plastic and fired in 
kiln and are used for roofing  
3.3  
ridge  tile  
solid unit of clay formed into a triangular shape covering the apex of two slopes on a pitched roof  
3.4  
defective  
tile or ridge that fails to comply with the relevant requirements of the specification  
3.5  
lot  
not more than 20 000 roofing tiles  of the same type and nominal dimensions, from one manufacturer, 
submitted for inspection and testing  
3.6  
drying shrinkage  
percentage reduction in length or volume of tiles on drying, due to the removal of the film of water which 
surrounds the individua l grains in the plastic form   
2 © UNBS 2019  – All rights reserved  
 
 3.8  
face of tile  
upper surface of the tile when fixed on the roof  
3.9  
back of tile   
lower surface of the tile when fixed on the roof  
3.10  
breaking load  
load at which the roofing tile or ridge breaks during testing  
3.11  
water absorption  
percentage amount of water absorbed by the roofing tile or ridge term  
4 Manufacture  
The roofing tiles shall be made from clay of even texture and shall be burnt throughout. They shall be free 
from irregularities, such as twists, bends,  cracks and laminations.  
The roofing tiles shall be free from impurities like particles of stone, lime or foreign materials visible to the 
naked eye either on the surface or on the fractured face of the tile obtained by breaking the tile. When struck, 
the tile shall give a characteristic ringing sound and when broken the fracture shall be clear and sharp at the 
edges.  
5 Physical requirements  
5.1 Appearance  
Tiles and ridges shall be well burnt and free from cracks and unslaked lime particles, and from ex crescences 
and depressions not forming part of the pattern of the tile or ridge. Surface grazing shall not be regarded as a 
defect.  
5.2 Shape  
5.2.1  Tile  
The patterns of Marseille, Mangalore, Portuguese and Roman are shown in figures 1, 2, 3, and 4 respe ctively.  
The gap at the corners of the tiles, when placed on plain surface in the normal position, shall be not more than 
8.0 mm. The design shall provide a good interlocking arrangement securing the roof against leakage or rain 
water. The tiles shall be free from faulty shape or any other defects liable to affect their strength or suitability 
for use.   DUS  816: 2019  
 
© UNBS 2019  – All rights reserved  3 
 
 
  
Figure 1 — Typical details of a Mangalore  tile   
4 © UNBS 2019  – All rights reserved  
 
 
  
Figure 2 — Typical Marseille tile  
Dimensions in millimetres  
  
Figure 3 — Typical Portuguese tile   
 DUS  816: 2019  
 
© UNBS 2019  – All rights reserved  5 
 
  
   
Figure 4 — Typical Roman tile   
5.2.2 Ridge  
The pattern of ridge is as shown in Figure 5.  
Dimensions in millimetres  
  
Figure 5 — Typical Ridge tile   
6 © UNBS 2019  – All rights reserved  
 
 5.3 Lugs (for Mangalore and Marseille tiles)  
5.3.1 Batten lug  
The tile shall have at least two ba tten lugs with a base thickness (thickness at the bottom) not less than 15 
mm and  a thickness at the top not less than 10 mm. The projection from the surface of the tile shall be 
between 7 mm and 12 mm (see Figure 1 and Figure 2).   
5.3.2  Eaves lugs  
The ti le shall have at least two eaves lugs with a base thickness not less than 15 mm and a thickness at the 
top not less than 10 mm. The projection from the surface of the lug shall be not less than 10 mm and shall be 
shaped to fit into the corrugations (see Fi gure 1 and Figure 2).  
5.4 Corrugations and cross ribs  
The cross -section of the roofing tile shall be such as to give the tile structural rigidity. This may be achieved by 
providing longitudinal corrugations with intermediate cross ribs or stiffeners (see  Figure 1 and Figure 2).  
5.5 Water absorption and breaking load  
Roofing tiles and ridges shall conform to the physical requirements as prescribed in Tables 1  and 2 
respectively.  
Table1 — Physical requirements for tiles  
S No.  Characteristic  Requiremen t  
Mangalore/Marseille  Roman/Portuguese  
(i)  Water absorption, %, max  14  14  
(ii)  Breaking load, N/mm, min    
   Average  
  Individual  4.5  
4.0  13.0  
10.0  
  
Table 2 — Physical requirements for ridges  
S No.  Characteristic  Requirement  
(i)  Water absorption, %, max  14  
(ii)  Breaking load, N/mm, min   
   Average  
  Individual  4.5  
4.0  
 
5.6 Dimensions and tolerances  
The manufacture shall declare the dimensions of the tiles , ridges  and the permissible deviation  shall be ± 5 
mm.   DUS  816: 2019  
 
© UNBS 2019  – All rights reserved  7 
 
 6 Performance requirements  
6.1 Weight  
The manufacturer shall declare weight per square meter (w/m2) for all tiles and ridges when dried at 105 °C to 
110 °C to constant weigh t and weighed, to the nearest 0. 01 kg  
6.2 Methods of test  
6.2.1  Water absorption  
The water absorption of tiles and ridges shall conform to the requirements laid down in Table 1 and Table 2, 
when determined in accordance with the test procedure laid down in Annex A.  
6.2.2  Permeability  
The tile and ridge shall be tested for permeability i n accordance with the procedure laid down in Annex B.  
The tiles and ridges shall be considered as conforming to the test if no water is found dripping at the bottom of 
the tile after the test.  
6.2.3  Breaking load  
The breaking load of the tiles and ridge s shall conform to the requirements laid down in Table 1 and Table 2, 
when determined in accordance with the test procedures laid down in Annex C and Annex D. The ridges shall 
be tested as the tiles.  
7 Marking   
7.1 The following information shall be legi bly impressed on the back of each tile and ridge:   
a) name, trade name or trade mark of the manufacturer; and  
b) batch identification number.  
Where the batch number on an individual tile or ridge is not possible, it shall be provided on a consignment 
slip in a  package or on the package.  
7.2 The tiles and ridges shall be packaged with a brochure bearing the following information;  
a) weight per square metre; and  
b) dimensions (length, width and thickness).   
8 Sampling and compliance with specification  
The following sa mpling procedure shall be applied in determining whether a lot complies with the relevant 
requirements of the specification. The samples so taken shall be deemed to represent the lot for the 
respective properties.   
8 © UNBS 2019  – All rights reserved  
 
 From the lot draw at random the number of  tiles given in column 2 of Table 3 relative to the lot size shown in 
column 1.  
Table 3 — Samples for inspection and tests  
1  2  3  
Lot size (number 
of tiles)  Sample size (number 
of tiles)  Number of defectives 
max  
Up to 1000  20  3  
1001 –   5000  30  4  
5001 –  10000  40  5  
10001 – 20000  55  6  
 
9 Inspection  
9.1 Appearance and marking  
Inspect each tile or ridge in the sample drawn in accordance with Clause 7 for compliance wi th the 
requirements .  
9.2 Shape and dimensions  
Check the dimension s and shape of each tile or ridge in the sample drawn in accordance with Clause 7 for 
compliance with the r equirements .  DUS  816: 2019  
 
© UNBS 2019  – All rights reserved  9 
 
 Annex  A 
(normative)  
 
Water absorption test  
A.1 Test specimen  
Ten tiles shall be randomly selected to form the sample size according t o the lot size as shown in Table 3 and 
used for this test.  
Ten ridges shall be randomly selected to form the sample size according to the lot size as shown in Table 3 
and used for this test  
A.2 Procedure  
Dry the ten tiles (or ridges) selected in an oven  at a temperature of 105 °C to 110 °C till they attain constant 
weight and then cool to ambient temperature and weigh.  
When cool, immerse the dry specimens completely in clean water at 24 °C to 30 °C for 24 h. Remove each 
specimen, wipe off the surface wa ter carefully with a damp cloth and weigh the specimen. Weigh the 
specimen to the nearest gram within three minutes after removing the specimen from the tank.  
A.3 Results  
A.3.1  The percentage water absorption is given by:  
 
     B – A   
       Ax 100 %  
where,  
A is the mass, in grams, of the dry specimen; and  
B is the mass, in grams, of the specimen after 24 h immersion in water.  
A.3.2  The average percentage water absorption of the ten tiles (or ridges) shall be calculated and reported 
as percentage water  absorption.   
10 © UNBS 2019  – All rights reserved  
 
 Annex  B 
(Normative)  
 
Permeability test  
B.1 Test specimen  
Ten tiles shall be randomly selected to form the sample size according to the lot size as shown in Table 3 and 
used for this test.  
Ten ridges shall be randomly selected to form the sample size according to the lot size as shown in Table 3 
and used for this test  
B.2 Apparatus  
The test shall be conducted in a rectangular trough (see Figure 6) which is open at the bottom, the dimensions  
at the bottom being equal to the size of the tile.  
B.3 Procedure  
B.3.1  The test shall be conducted at a temperature of 27 °C ± 2 °C and relative humidity of 65 % ± 5 %.  
B.3.2  The tile (or ridge) shall be fitted at the bottom of the trough and the space  between the tile and the 
sides of the trough plugged water -tight with suitable material like wax, bitumen, etc.  
Water shall be poured into the mould so that it stands over the lowest tile surface to a height of 50 mm.  
B.3.3  The water in the trough shall  be allowed to stand for a period of six hours. The bottom of the tile shall 
then be carefully examined to see whether the water has seeped through the tile.  DUS  816: 2019  
 
© UNBS 2019  – All rights reserved  11 
 
 Annex  C 
(Normative)  
 
Determination of breaking l oad (for Mangalore and Marseille tiles)  
C.1 Test specimen  
Ten tiles shall be randomly selected to form the sample size according to the lot size as shown in Table 3 and 
used for this test.  
C.2 Apparatus  
A suitable form of apparatus is shown in Figure 7 , consisting of two parallel self -aligning steel bearers, with the 
bearing surface rounded to 38 mm diameter, so placed that the distance between the centres could be 
altered. The load is applied through a third steel bearer of similar shape midway between  and parallel to the 
supports. The length of all the bearers shall exceed the maximum width of the tile under test.  
C.3 Procedure  
Test ten tiles in wet condition after soaking them in water at 20 ºC ± 2 ºC for 24 h. Support the tile centrally on 
the bear er set with a span of 25 cm and resting on the bottom surface. Apply the load with the direction of the 
load perpendicular to the span, at a uniform rate of 440 N/min to 540 N/min.  
C.4 Results  
Report the average breaking load from the ten tests in N/mm w idth.  
12 © UNBS 2019  – All rights reserved  
 
 Annex  D 
(Normative)  
 
Determination of breaking load (for Roman and Portuguese tiles)  
D.1 Test specimen  
Ten tiles randomly selected to form the sample size according to the lot size as shown in Table  3 shall be 
used for this test.  
Ten ridges shall be randomly selected to form the sample size according to the lot size as shown in Table 3 
and used for this test  
D.2 Apparatus  
This test may be conducted with any standard compression testing machine wit h provision for adjusting the 
rate of loading. A typical arrangement is shown in Figure 8.  
D.3 Procedure  
Ten tiles or ridges in wet condition after soaking in water for 24 h shall be tested. The two longitudinal edges 
of the Roman or Portugal tile shall be kept, in normal position, over two strips of 25 mm thick rubber sheet 
placed on the table of the testing machine.   
The load shall be applied to the tile or ridges by means of a wooden block of size 75 mm x 100 mm x 300 mm 
lined with rubber at the botto m, located symmetrically. The load shall be applied to the block at a uniform rate 
of 450 N/min – 600 N/min.  
D.4 Results  
The individual breaking strength shall be obtained by dividing the breaking load by the width of the tile and the 
average of the valu e shall be calculated. The result shall be expressed in N/mm width.   
  
  DUS  816: 2019  
 
© UNBS 2019  – All rights reserved  13 
 
 Figure 6 — Arrangements for permeability test  
  
Figure 7(a) — Apparatus for testing transverse strength  
  
  
Figure 7(b) — Sectional view of apparatus for testing transverse stre ngth  
  
   
14 © UNBS 2019  – All rights reserved  
 
 Figure 7(c) — Sectional view of apparatus for testing transverse strength  
  
  
Figure 8 — Arrangements for flexural strength test of Roman tile  
 DUS  816: 2019  
 
© UNBS 2019  – All rights reserved  15 
 
 Bibliography  
[1] KS 431 -1: 2006 , Clay roofing tiles — Specification  
 DUS 816: 2019  
© UNBS 2019  – All rights reserved  17 
 
 Certification marking  
Produc ts that conform to Uganda standards may be marked with Uganda National Bureau of Standards 
(UNBS) Certification Mark shown in the figure below.  
The use of the UNBS Certification Mark is governed by the Standards Act, and the Regulations made 
thereunder. T his mark can be used only by those licensed under the certification mark scheme operated by 
the Uganda National Bureau of Standards and in conjunction with the relevant Uganda Standard. The 
presence of this mark on a product or in relation to a product is an assurance that the goods comply with the 
requirements of that standard under a system of supervision, control and testing in accordance with the 
certification mark scheme of the Uganda National Bureau of Standards. UNBS marked products are 
continually c hecked by UNBS for conformity to that standard.  
Further particulars of the terms and conditions of licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 DUS 816: 2019    
 
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