Belgium gets the best, UK gets the worst

Sir; A number of articles and letters about the quality of roofing slates have been published recently. Several have referred to the testing and control of slates in Belgium.

As the person responsible for the certification and independent control of slate quality in Belgium since 1981, I would like to give a Belgian perspective.

First, quality control. In Belgium prior to 1981 there was little or no quality control of the slates with the result that a lot of poor or bad slates were being sold, many at high prices.

The government reacted to this unsatisfactory situation by creating a commission to prepare a product standard, test methods and a certification and control system for all imported slates.

Since then, a lot has changed. In Belgium you will only find the best slates available. The private sector has voluntarily adopted the same controls because they have confidence in the way the system works and the quality of the slates it approves.

Belgium now has 50 certified slates from six countries which provides it with a good choice of all colours and all sizes, but always of good quality. All the manufacturers like Belgium's system.

A control system is not expensive and will cost each manufacturer only about œ700 a year. The certification costs about œ4,000 for three years including quarry check, tests, printing and distribution of the certificate in Belgium and for the copies for the owner.

Nowadays nearly all bad Spanish slates go to Britain. This is well-known in Spain. Some also go to France because of similar control problems.

I believe the quality control of all slates imported into Britain could be carried out for œ200,000.

Professor J P Cnudde

Slate and Stone

International Consultant

University of Ghent