UGANDA STANDARD  
  US 816
First Edition
2008-12-11
 
 
Reference numbe r
US 816: 2008
 © UNBS 2008 
  
Specification for clay roofing tiles and ridges 
 US 816:2008 
© UNBS 2008 – All rights reserved         ii 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 correct application  
© UNBS 2008  
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, in cluding 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: 256 414 505 995 
Fax: 256 414 286 123 
E-mail: unbs@infocom.co.ug
Web: www.unbs.go.ug  US 816:2008 
iii        © UNBS 2008 – All rights reserved  
 
 Contents Page 
Foreword .............................................................................................................................................................v  
1 Scope ......................................................................................................................................................1  
2 Terms and definitions ...........................................................................................................................1  
3 Manufacture ...........................................................................................................................................2  
4 Physical requirements ..........................................................................................................................2  
4.1 Appearance ............................................................................................................................................2  
4.2 Shape ......................................................................................................................................................2  
4.2.1 Tile...........................................................................................................................................................2  
4.2.2 Ridge .......................................................................................................................................................2  
4.3 Lugs (for Mangalore and Marseille tiles) .............................................................................................6  
4.3.1 Batten lug ...............................................................................................................................................6  
4.3.2 Eaves lugs ..............................................................................................................................................6  
4.4 Corrugations and cross ribs ................................................................................................................6  
4.5 Water absorption and breaking load ...................................................................................................6  
4.6 Dimensions and tolerances ..................................................................................................................6  
4.6.1 Mangalore and Marseille tiles ..............................................................................................................6  
4.6.2 Roman tiles ............................................................................................................................................7  
4.6.3 Portuguese tiles .....................................................................................................................................7  
5 Performance requirements ...................................................................................................................7  
5.1 Weight .....................................................................................................................................................7  
5.1.1 Mangalore tiles ......................................................................................................................................7  
5.1.2 Marseille tiles .........................................................................................................................................7  
5.1.3 Roman tiles ............................................................................................................................................7  
5.1.4 Portuguese tiles .....................................................................................................................................7  
5.1.5 Ridges .....................................................................................................................................................7  
5.2 Methods of test ......................................................................................................................................7  
5.2.1 Water absorption ...................................................................................................................................7  
5.2.2 Permeability ...........................................................................................................................................7  
5.2.3 Breaking load .........................................................................................................................................8  
6 Marking ...................................................................................................................................................8  
7 Sampling and compliance with specification .....................................................................................8  
8 Inspection ...............................................................................................................................................8  
8.1 Appearance and marking .....................................................................................................................8  
8.2 Shape and dimensions .........................................................................................................................8  
Annex A (normative)  Water absorption 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 breaki ng load (for Mangalore and Marseille tiles) .....................11  
C.1 Test specimen ............................................................................................................................... .......11  
C.2 Apparatus ............................................................................................................................... ..............11  
C.3 Procedure ............................................................................................................................... ..............11  US 816:2008 
iv        © UNBS 2008 – All rights reserved  
 
 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  US 816:2008 
v        © UNBS 2008 – All rights reserved  
 
  
Foreword 
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry  of Tourism, Trade and 
Industry established under Cap 327, of the Laws of Uganda.  UNBS is mandated to co-ordinate the 
elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex A limentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT/SPS Agr eements of the World Trade Organisation (WTO). 
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a gi ven field or area and consists of representatives of 
consumers, traders, academician s, manufacturers, governme nt and other stakeholders. 
Draft Uganda Standards adopted by the Technical Committ ee 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 Standards by the National Standards Council.  
Committee membership 
The following organizations were represented on the Technical Committee for Building and civil engineering standards, UNBS/TC 3, in the dev elopment of this standard:  
• Africana Clays Ltd. 
• Lweza Clays Ltd. 
• Makerere University 
• Ministry of Energy and Mineral Development (Department of Geological Survey and Mines)  
• Ministry of Works and Transport 
• Pan Kajjansi Brick and Tiles Works Ltd. 
• Uganda Clays Ltd. 
• Uganda National Bureau of Standards 
 UGANDA STANDARD US 816: 2008
 
© UNBS 2008 – All rights reserved         1 Specification for clay roofing tiles and ridges 
1 Scope 
This specification covers clay roofing tiles and ridges intended for use as roof covering where durability and 
appearance are required to provide a weather-resistant surface of specified design. This standard specifies 
requirements for Mangalore, Marseilles, Roman and Portuguese roofing tiles a nd clay roofing ridges. 
2 Terms and definitions 
For the purposes of this standard, the following terms and definitions shall apply. 
2.1  
clay 
earthy or stony mineral aggregate consisting essentially  of hydrous silicate of alumina; plastic when 
sufficiently pulverized and wetted; rigid when dry; and vitreous when fired to a sufficiently high temperature 
2.2 
clay roofing tile 
solid unit of clay formed into any of a range of genera lly rectangular planar shapes while plastic and fired in 
kiln and are used for roofing 
2.3 
ridge tile 
solid unit of clay formed into a triangular shape covering the apex of two slopes on a pitched roof 
2.4 
defective 
tile or ridge that fails to comply with t he relevant requirements of the specification 
2.5 
lot 
not more than 20 000 roofing tiles of the same type and nominal dimensions, from one manufacturer, submitted for inspection and testing 
2.6 
drying shrinkage 
percentage reduction in length or volume of tiles on drying, due to the removal of the film of water which surrounds the individual grains in the plastic form 
2.8 
face of tile 
upper surface of the tile when fixed on the roof 
2.9 
back of tile  
lower surface of the tile when fixed on the roof 
2.10 
breaking load 
load at which the roofing tile or ridge breaks during testing 
2.11 
water absorption 
percentage amount of water absorbed  by the roofing tile or ridge US 816:2008 
2        © UNBS 2008 – All rights reserved  
 
 3 Manufacture 
The roofing tiles shall be made from clay of even text ure 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 part icles 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 br eaking 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. 
4 Physical requirements 
4.1 Appearance 
Tiles and ridges shall be well burnt and free from cracks  and unslaked lime particles, and from excrescences 
and depressions not forming part of the pattern of the tile or ridge. Surfac e grazing shall not be regarded as a 
defect. 
4.2 Shape 
4.2.1 Tile 
The patterns of Marseille, Mangalore, Portuguese and Roman are shown in figures 1, 2, 3, and 4 respectively. 
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 ar rangement 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.  
4.2.2 Ridge 
The pattern of ridge is as shown in Figure 5. US 816:2008 
3        © UNBS 2008 – All rights reserved  
 
 Dimensions in millimetres 
 
 
L = 410 mm ± 5 mm, B = 235 mm ± 5 mm 
Figure 1 — Typical details of a Marseille tile 
 
 
 
 
 US 816:2008 
4        © UNBS 2008 – All rights reserved  
 
 Dimensions in millimetres 
 
Figure 2 — Mangalore tile 
 
Dimensions in millimetres 
 
Figure 3 — Portuguese tile  
 US 816:2008 
5        © UNBS 2008 – All rights reserved  
 
 Dimensions in millimetres 
 
 
Figure 4 — Roman tile  
 
Dimensions in millimetres 
 
Figure 5 — Ridge tile  
 US 816:2008 
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 4.3 Lugs (for Mangalore and Marseille tiles) 
4.3.1 Batten lug 
The tile shall have at least two batten 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 proj ection from the surface of the tile shall be 
between 7 mm and 12 mm (see Figure 1 and Figure 2).  
4.3.2 Eaves lugs 
The tile 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 Figure 1 and Figure 2). 
4.4 Corrugations and cross ribs 
The cross-section of the roofing tile s hall be such as to give the tile struct ural rigidity. This may be achieved by 
providing longitudinal corrugations with intermediate cross ribs or stiffeners (s ee Figure 1 and Figure 2). 
4.5 Water absorption and breaking load 
Roofing tiles and ridges shall conform to the physical requirements as prescribed in Tables 1and 2 respectively. 
Table1 — Physical requirements for tiles 
Requirement S No. Characteristic 
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 
 
4.6 Dimensions and tolerances 
4.6.1 Mangalore and Marseille tiles 
The tiles shall have an overall length of 410 mm and an overall width of 235 mm with a permissible deviation of ± 5 mm. 
Thickness shall be not less than 10 mm and not more than 15 mm. The measurement shall be done along the troughs. US 816:2008 
7        © UNBS 2008 – All rights reserved  
 
 The minimum overlap shall be 60 mm lengthwise and 25 mm width wise. 
4.6.2 Roman tiles  
The tiles shall be 375 mm long with a permissible deviation of ± 5 mm and shall be not less than 15 mm thick 
and other dimensions shall be as shown in Figure 4. 
The minimum overlap shall be 30 mm lengthwise and 30 mm width wise. 
4.6.3 Portuguese tiles 
The dimensions of the tiles shall be as shown in Figure 3, with permissible deviation of ± 5 mm. 
5 Performance requirements 
5.1 Weight 
5.1.1 Mangalore tiles 
The average weight of t en tiles, when dried at 105 °C to 110 °C to constant weight and weighed, to the nearest 
0,01 kg, shall not be less than 2.2 kg and not more than 2.65 kg. 
5.1.2 Marseille tiles 
The average weight of t en tiles, when dried at 105 °C to 110 °C to constant weight and weighed, to the nearest 
0.01 kg, shall not be less than 2.2 kg and not more than 2.65 kg. 
5.1.3 Roman tiles 
The average weight of t en tiles, when dried at 105 °C to 110 °C to constant weight and weighed, to the nearest 
0.01 kg, shall not be less than 1,6 kg and not more than 1.85 kg. 
5.1.4 Portuguese tiles 
The average weight of t en tiles, when dried at 105 °C to 110 °C to constant weight and weighed, to the nearest 
0,01 kg, shall not be less be than 3.3 kg and not more than 3.60 kg. 
5.1.5 Ridges 
The average weight of ten ridges, when dried at 105 °C to 110 °C to constant weight and weighed, to the 
nearest 0.01 kg, shall not be less than 2.2 kg and not more than 2.65 kg. 
5.2 Methods of test 
5.2.1 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. 
5.2.2 Permeability 
The tile and ridge shall be tested for permeability in 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. US 816:2008 
8        © UNBS 2008 – All rights reserved  
 
 5.2.3 Breaking load 
The breaking load of the tiles and ri dges shall conform to the requiremen ts 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. 
6 Marking  
The following information shall be legibly im pressed on the back of each tile and ridge:  
a) name, trade name or trade mark of the manufacturer; and 
b) batch identification number. 
7 Sampling and compliance with specification 
The following sampling procedure shall be applied in deter mining 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. 
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 
 
8 Inspection 
8.1 Appearance and marking 
Inspect each tile or ridge in the sample drawn in accordance with Clause 7 for compliance with the requirements of 4.1 and 6. 
8.2 Shape and dimensions 
Check the dimensions and shape of each tile or ridge in  the sample drawn in accordance with Clause 7 for 
compliance with the requirements of 4.2 - 4.4 and 4.6. 
 US 816:2008 
9        © UNBS 2008 – All rights reserved  
 
 Annex A 
(normative) 
 
Water absorption test 
A.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 
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 water carefully with a damp cloth and weigh the specimen. Weigh the specimen to the nearest gram within three mi nutes after removing the specimen from the tank. 
A.3 Results 
A.3.1 The percentage water absorption is given by: 
% 100 xAA  B− 
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 absorp tion of the ten tiles (or ridges) shall be calculated and reported 
as percentage water absorption. US 816:2008 
10        © UNBS 2008 – 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 Fi gure 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 su itable 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 whethe r the water has seeped through the tile.  US 816:2008 
11        © UNBS 2008 – All rights reserved  
 
 Annex C 
(normative) 
 
Determination of breaking load (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, cons isting of two parallel self-aligning steel bearers, with 
the bearing surface rounded to 38 mm diameter, so plac ed 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 bearer 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 fr om the ten tests in N/mm width.  US 816:2008 
12        © UNBS 2008 – 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 ac cording 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 compress ion testing machine with 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 me ans of a wooden block of size 75 mm x 100 mm x 300 mm 
lined with rubber at the bottom, 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 divi ding the breaking load by the width of the tile and the 
average of the value shall be calculated. The result shall be expressed in N/mm width.  US 816:2008 
13        © UNBS 2008 – All rights reserved  
 
  
 
Figure 6 — Arrangements for permeability test 
 
Figure 7(a) — Apparatus for testing transverse strength 
 
 
Figure 7(b) — Sectional view of appa ratus for testing transverse strength US 816:2008 
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Figure 7(c) — Sectional view of appa ratus for testing transverse strength 
 
 
Figure 8 — Arrangements for flexural strength test of Roman tile 
 
 
 
 
 
  US 816:2008 
15        © UNBS 2008 – All rights reserved  
 
 Certification marking 
Products 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 gove rned by the Standards Act, and the Regulations made 
thereunder. This mark can be used only by those licens ed under the certification mark scheme operated by 
the Uganda National Bureau of Standards and in co njunction 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 checked 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.  
 
 US 816: 2008 
 
ICS nn.nnn.nn 
Price based on 21 pages 
© UNBS 2008– All rights reserved