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Cast Stone Questions & Answers

About cast stone

What Is Cast Stone?

Cast Stone is a special form of simulated stone, also known as reconstructed or reconstituted stone
It is defined by the United Kingdom Cast Stone Association (UKCSA) as any product manufactured with aggregate and cementations binder intended to resemble and be used in a similar way to natural stone.
Cast Stone is either homogenous throughout of consists of a facing and backing mix.

Semi dry,wet-cast or fibre reinforced cast stone

What are the different types Cast Stone?

Cast Stone is produced by one of three processes: Firstly as a semi-dry process which gives the components a slightly open textured face, similar to sawn quarried stone.
Secondly, as a wet cast process which gives a much closer face texture and allows large components and those with complex reinforcement to be produced.
Thirdly as fibre reinforced cast stone, a process incorporating alkali resistant extended fibre reinforcement that allows thin and lightweight sections to be produced.

Cast Stone as an alternative to Natural Stone

How does Cast Stone compare with Natural Stone?

Cast Stone resembles quarried natural stone in most aspects.
The colour and texture of most stones can be matched using crushed rock fines and/or carefully selected and graded natural sands.
Complex shapes which could not be produced in natural stone, can in most cases be manufactured in Cast Stone. In addition it is possible to reinforce cast stone elements in order to produce a structural unit.

Specifying cast stone

What specification is Cast Stone manufactured and supplied to?

Cast Stone is usually produced to BS 1217:2008 although certain machine made components by certain manufacturers may be manufactured to BS EN 771-5; Manufactured Stone Units.
Cast Stone manufactured by UKCSA members is produced to a higher compressive strength standard than BS 1217 and members are audited to ensure that Quality, Environmental and Health Requirements are reached.

Cast Stone Technical Manual

How should Cast Stone be handled on site?

Cast Stone should be handled with care.
The units must be handled and stored with care to prevent chipping, cracking or staining, especially those with finely detailed profiles.
Long slender units should be handled in the plane they are designed to be installed unless otherwise advised by the manufacturer.
A typical example of a product which may not be handled in the same plane as it is installed would be a 65mm thick cill. Unless supplied in short lengths, this unit can suffer deflection cracks.

Cast Stone Technical Manual

How should Cast Stone be installed?

Cast Stone units should only be installed by suitably trained personnel. It should be treated in a similar manner to natural quarried stone.
During construction the units should be installed with due regard to the implications of their shape and weight.
Components should be protected at the end of each day and it is advisable to protect finished work.
The fixing of Cast Stone should be considered at design stage so that any required fixings are incorporated during production.
Cast Stone units should be designed to minimise site cutting and are typically calculated to be fixed with joint sizes of between 5-10mm.
It is vital to specify the correct mortar designation, which may be different to that of the surrounding masonry.

Cast Stone CE Marking

Does Cast Stone need to be CE Marked?

A CE Mark can only be affixed to a product produced and supplied to a harmonised European Standard and as cast stone is normally supplied to the British Standard BS 1217 it is not possible to CE Mark to that standard, in fact it is illegal to do so.
However, some smaller units, without reinforcing or fixings, and in particular standard size ashlar blocks, may be supplied to alternative standards which may require CE Marking.


What is UKCSA?

UKCSA, the United Kingdom Cast Stone Association is an independent trade association which was founded in 1991.
It acts to establish and maintain the highest standards of product quality, usage and social responsibility and represents the manufacturers that lead the field in their discipline. The Association also promotes the merits of cast stone to the market.
In practical terms, the Association defines strict levels of technical performance for material produced by its members and those members are committed to ensuring that their products will be of a consistently high quality which gives specifiers and users confidence in the product.

Membership of UKCSA

Can we join UKCSA?

Full Membership of UKCSA, the United Kingdom Cast Stone Association, is open to all UK based cast stone manufacturers who manufacture cast stone to the exacting requirements of the Association. All new applicants are rigourously vetted to ensure that they are able to uphold the standards of the Association.
Associate Membership of UKCSA is open to all other companies and individuals with a UK operation who are involved in materials and trades associated with the cast stone industry.

Contact UKCSA for answers


Cast Stone is an established and recognised product used widely in the construction industry. The UKCSA acts as the reference point for Cast Stone in the UK and provides a wealth of detailed information and guidance via this website.
The standards applied by UKCSA exceed the British Standard to ensure the product performs in build for the lifetime of the project and it is advisable to specify to the UKCSA specification and furthermore the UKCSA manufacturing members are committed to service your requirements in full.

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All data on this website is for information only and is to the best of our knowledge current and correct. UKCSA presents this information without guarantee and cannot be held liable for any consequential claims. UKCSA members will be able to advise you in more detail on all aspects of cast stone specific to their products and supply.

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