KENYA STANDARD              DKS 2928 : 2020  
   
 
 
 
 
 
 
 
 
 
 
 
 
 
Plastic Composite Roofing tiles —
Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
© KEBS 20 19                        First Edition  2019 
 
  DKS 2928 : 2020 
 
   © KEBS 201 9 — All rights reserved  ii TECHNICAL COMMITTEE REPRESENTATION  
The following organizations were represented on the Technical Committee:  
 
Kenya Industrial Research and Development Institute  
Space and Style Ltd  
Blackberry House LTD  
Consumer Information Network  
Edge& Atelier Limited  
Kangemi Jua Kali Association  
Edge& Atelier Limited  
Kepsa/Kenya National Federation of Jua Kali  
Sub county Health Services, Kamukunji  
Kenya Bureau of standards - secretariat  
 
 
 
REVISION OF KENYA STANDARDS  
 
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improvements to published standards, addressed to the Managing Director, Kenya Bureau of Standards, are 
welcome.  
 
 
 
 
 
© Kenya Bureau of Standards, 20 19 
Copyright. Users are reminded that by virtue of Section 25 of the Copyright Act, Cap. 12 of 2001  of the Laws of Kenya, copyr ight subsists 
in all Kenya Standards and except as provided under Section 26 of this Act, no Kenya Standard produced by Kenya Burea u of Standards 
may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing f rom the 
Managing Director . 
 
 
 
    
  KENYA STANDARD                DKS 2928 : 2020  
© KEBS 2019 — All rights reserved  iii  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Plastic Composite Roofing Tiles —
Specification   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
KENYA BUREAU OF STANDARDS (KEBS)  
 
Head Office:  P.O. Box 54974, Nairobi -00200, Tel.: (+254  020) 605490, 602350, Fax: (+254 020)  604031  
E-Mail: info@kebs.org,  Web:http://www.kebs.org  
 
Coast Region           Lake Region           Rift Valley Region  
P.O. Box 99376, Mombasa -80100      P.O. Box 2949, Kisumu -40100         P.O. Box 2138, Nakuru -20100  
Tel.: (+254  041) 229563, 230939/40     Tel.: (+254 057) 23549, 22396       Tel.: (+254 051) 210553, 210555  
Fax: (+254  041) 229448         Fax: (+254 057) 21814  
 
 
 
 
 
 
 
  DKS 2928 : 2020 
 
   © KEBS 201 9 — All rights reserved  iv Foreword  
 
This Kenya Sta ndard was prepared by the Construction Technology  Technical Committee under the guidance 
of the Standards Projects Committee and it is in accordance with the procedures of the Kenya Bureau of 
Standards.  
 
 
 
 
Acknowledgement is hereby made for the assistance received from these sources . 
 
 
 
 
 
 
  
KENYA STANDARD                        CD –ENG -xxxx : 2019 
 
© KEBS 2015 —  All rights reserved    1   
Plastic Composite Roofing Tiles —Specification   
 
1. Scope  
 
This s pecification applies to plastic composite  roofing tiles of plain and interlocking types.   It establishes 
minimum standards for fit and finish, quality of material used in the manufacture and for dimensional 
requirements related to side -lap, location of fixing and sizes.  
2. Normative references  
 
The following referenced documents are indispensable for the application of this document. For dated 
references, only the edition cited applies. For undated references, the latest edition of the referenced document 
(including any amendments) applies. Informat ion on currently valid national and international standards can 
be obtained from the Kenya Bureau of Standards.  
 
KS 444:1984:  Specification for concrete roofing tiles  
 
3. Terms and Definitions  
For the purpose of this document the following terms and definitions apply  
3.1.  
acceptable  
A tile that has been found without defects after inspection and testing  
3.2.  
unacceptable  
A tile that fails in one or more respects to comply with the appropriate requirements of the specification.  
3.3.  
stated length/width  
The length/width that Is the manufacturer’s equivalent to the appropriate nominal length/nominal width 
specified in Table 1.  
 
3.4.  
nominal size  
A size of paving block, normally expressed in terms of dimensions of length, width and thickness, specified 
for its manufacture, to which its actual size should conform within specified deviations.  
 
4. General requirements  
4.1. The blocks shall be made from suitable plastic and sand. They shall have plane rectangular faces 
with parallel sides and shall have sharp straight edge s at right angle. They shall have a fine compact 
and, uniform texture . 
4.2. The bricks shall be free from excessive winding or bowing and where necessary all external angles 
shall be right angles. The bricks shall be tested for trueness of shape as specified in  3.2.1 to 3.2.3  
4.3. Winding or Bowing in the Length Dimension - The bricks shall be placed between two parallel straight 
edges running along the length (see Fig. 1) and the distance between either straight edge and the 
adjacent face of the brick at any point s hall not be more than 5 mm.   
4.4. Angles Between Sides and Joining Edges - Any variation from a right angle in the angle contained by 
any side and a joining edge shall be limited so that if a builder’s steel square is placed against the 
angle, the maximum dist ance between the inner edge of the square and the side shall not be more 
than 5 mm (see Fig. 2). 
  
   © KEBS 201 9 — All rights reserved  2  
 
 
 
Fig 2 Test for correcting of edges  
 
 
 
5. Thermal resistance and thermal conductivity  
 
Thermal resistance and thermal conductivity shall be based upon measurements carried out in accordance 
with EN 12667 or EN 12939 for thick products.  
 
The thermal resistance and the thermal conductivity shall be determined in accordance with annex A and 
declared by the manufacturer according to the following:  
 the refere nce mean temperature shall be 10 °C;  
 the measured values shall be expressed with three significant figures;  
 
NOTE Zeros on the left hand side are not counted as significant figures.  
 
 the thermal resistance, RD, shall always be declared. The thermal conductivity, ƛ D, shall be declared 
where possible;  
 the declared thermal resistance, RD, and the declared thermal conductivity, ƛ D, shall be given as limit 
values representing at least 90 % of the production, deter mined with a confidence level of 90 %;  
 the value of thermal conductivity, ƛ 90/90, shall be rounded upwards to the nearest 0,001 W/(m·K) and 
declared as  ƛ D in levels with steps of 0,001 W/(m·K);  
 the declared thermal resistance, RD, shall be calculated fro m the nominal thickness, dN, and the 
corresponding thermal conductivity, ƛ  90/90, unless measured directly. For products for which 
compressibility is measured (see 5.1.1)) the RD shall be calculated using dL instead of dN. For the 
calculation of the declar ed thermal conductivity, ƛ  D, related to the corresponding nominal thickness, 
factors for the thickness effect conversions are given in annex B;  
 the value of thermal resistance, R90/90, when calculated from the nominal thickness, dN, and the 
corresponding thermal conductivity, R 90/90, shall be rounded downwards to the nearest 0,05 m2·K/W, 
and declared as RD in levels with steps of 0,05 m2·K/W;  
CD/ENG X:  2019  
 
© KEBS 2020  — All rights reserved  3  the value of R90/90, for those products for which only the thermal resistance is measured directly, shall 
be rounde d downwards to the nearest 0,05 m2·K/W, and declared as RD in levels with steps of 0,05 
m2·K/W  
 
6. Fire resistance  
The tiles should be accordance to  the requirements outline in the building code  
7. Dimensions and tolerance  
7.1. Dimensions  
The standard dimensions of the tiles shall be as follows:  
Length: 410mm  
Width: 321mm  
Side Lap: 19mm  
Height: 9.82mm . 
 
7.2. Tolerances  
The length and widths can deviate from the specified values up to ±5 percent; while the height can deviate 
from the specified value by ±3 percent  
 
8. Compressive strength  
8.1. The minimum average crushing strength of the bricks when determined in accordance with the  
procedure laid down in Appendix A shall  be 12.4 N/mm2. 
8.2. The crushing strength of any individual brick shall not fall below the minimum average crushing 
strength by more than 20 percent.  
9. The water absorption of the tiles by weight. When tested in accordance with the procedure laid down in 
KS 444  shall not exceed 15 percent.  
 
NOTE - An alternate value of 10 percent. Maximum water content may also be agreed upon. if specified by the purchaser.  
 
 
10. Color fastness  
 The tile should comply to KS ISO 105-B03:1994  
11. Sampling  
For checking the requirements specified in 4 to  6.  25 tiles shall be selecte 6d at random for every 2 500 tiles 
or fraction thereof in a lot. by the purchaser (or his representative). The number of tiles taken for tests shall be 
not less than 25 in anyone lot.  
12. Marking  
The following particulars relating to roofing tile  made in accordance with this standard shall be indicated clearly 
on the  delivery note, invoice, manufacturer’s or supplier’s certificate or brochure supplied with the consignment 
of blocks:  
 
a) the name, trade mark or other means of identification of the manufacturer;  
 
b) the number of this standard;  
 
c) nominal dimensions.  
 
 
 
 
  
   © KEBS 201 9 — All rights reserved  4  
Annex A  
 (normative)  
Determination of breaking load for composite roofing tile  
 A.1 Test principle  
Verification of the ability of the product to resist a centered load when subjected to flexion on two simple 
bearers as shown in Figure A.1.  
A.2 Test specimen  
Ten tiles shall be randomly selected each one consisting of a whole tile dried in ambient air. If the tiles have 
been subjected to humidity, they shall be dried in a laboratory atmosphere before testing (temperature +10 
0C and +40 0C, relative hu midity less than 90 %).  
 A.3 Apparatus  
 A.3.1 A device that applies a load with an accuracy of 2 %, and a load increase rate of 0.05 kN/s.  
 A.3.2 A system used as lower bearers, and, depending on the type of tile, either made up of rods or half -
rods, on e of which is articulated in order to rotate in a vertical plane and obtain as uniform a load distribution 
as possible on the sample, or for some over and under tiles by a flat plate supporting the tile.  
 A.3.3 A round steel bar, fitted to the bottom of t he load application device. The upper and lower bearers 
shall have a radius of between 15 mm and 20 mm and a length greater than the width of the tile to be tested.  
 A.3.4 A set of hardwood shims, used for chocking the lower bearers.   
 A.3.5 A hardwood or moulded plaster shim, adopted to the shape of the tile.  
 A.4 Procedure   Place the tile on two lower bearers in the same horizontal plane (see Figure A.1) so that:   i) 
the first bearer is in the position normally occupied by the batt en;  
 ii) the second bearer is separated from the first by a distance equal to two -thirds of the overall length (L) of 
the tile.  
 In order to ensure that the tile remains in stable position, use wooden shims of the same width as the upper 
shim to support the tile on the lower bearers, and a shim adopted to fit the shape of the upper bearer.  
The contoured piece of wood has a strip of rubber on the upper part in contact with the tile.  
The width of the contoured hardwood shim or moulded plaster shim shall b e equal to the diameter of the load 
application bar.  
Place the assembly in such a position that the load application bar is parallel to the two lower bearers and 
equidistant from both .  
Note the difference between the bearer axis.  
 
 
 
 
 
 
 
 
 
 CD/ENG X:  2019  
 
© KEBS 2020  — All rights reserved  5