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Terra Cotta Specification

Drying blocks for Technical Specifications

Physical properties of terra cotta and faience, tested in accordance with the British Standards (BS) and the American Society for Testing and Materials (ASTM), by Ceram Research, British Ceramic Research Ltd.

All of our processes are controlled by a Quality Management System complying to ISO9001:2008, which we believe is the absolute minimum our customers should come to expect.

All of our products exceed the test requirements shown in the standards below:

Test Standard Specification
Compressive Strength ASTM C67 8000 psi +/- 500
Absorption (24hr soak) ASTM C67 7.9% max
Absorption ( 5hr boil) ASTM C67 11.9% max
Saturation coefficient ASTM C67 0.69 max
Glaze Absorption - 0.15% max
Freeze/Thaw Resistance ASTM C67 (300 cycles) 300 cycles
Craze Resistance ASTM C126 Pass
Craze Resistance ASTM C424 Pass
Refractoriness ASTM C24 >1500°C
Imperviousness AIA File No.9 Pass
Chemical Resistance AIA File No.9 Pass
Glaze Crazing AIA File No.9 Pass
Glaze Adhesion AIA File No.9 Pass

Dimensional tolerance for architectural terra cotta is +/- 2%
View our UK Specifications here


Durability example

Vitrified ceramic materials are unaffected by ageing, weathering, ultraviolet radiation or atmospheric pollution.

For some restoration projects or specific design requirements, it may be more important to achieve a good aesthetic match than to achieve specific physical properties and tolerances. Each project should be individually considered.

Fixing and Cleaning

The importance of employing companies that are competent or who have years of experience in such matters can not be stressed highly enough.
All too often we see some of the finest buildings having been incorrectly cleaned, causing irreparable damage to materials. The fixing of terra cotta and faience should not be underestimated. It is only with experience that their natural characteristics are appreciated. Shaws of Darwen will gladly advise on both these important matters and recommend specialist companies able to carry out such work.

For general site handling, fixing, safety and physical property specifications, please contact our terra cotta sales office.