As a regular reader of Building I was particularly interested in the article "Recyled content" (31 March, page 71).

However I was rather disappointed by certain conclusions reached in respect of raised floors. First, the article stated that galvanized-steel raised floors have a recycled content of only 15%, whereas the facts are that some manufacturers source their chipboard core from UK producers that use almost entirely recycled raw materials.

Second, the statement that "calcium sulphate raised floors were similar to other systems but heavier" is also incorrect. In the UK raised floors used in commercial offices are normally designed to meet the PSA medium grade specification, the world's most exacting standard, which calls for a safety factor of three (calcium sulphate systems used on the European mainland are designed and manufactured to a safety factor of only two).

Furthermore the construction industry has for many years installed raised floors in the early stages of the construction programme using high-quality systems to assist in the protection of underfloor services and as a working platform. This practice would be impossible with calcium sulphate floors as they would be unable to withstand the rigors of normal construction works.

Finally, and although the article concerned only considered the recycled element, we should also consider the energy used in producing the raw materials, the transport costs (in terms of environmental damage) and the energy "wasted" in the manufacturing process of the system. Taking all these factors into account perhaps you should revisit this subject!

Terry Newman, managing director, Kingspan Access Floors