On Mon, 19 Apr 2004 12:37:25 +0100, a particular chimpanzee named The Natural Philosopher randomly hit the keyboard and produced:
An alteration is only material if it adversely affects a Relevant Requirement (currently Part A- structure, Part B- fire safety and Part M- access & facilities for disabled people), or a controlled service or fitting (drainage and waste disposal, combustion appliances, and for dwellings, replacement windows or central heating boilers, vessels, etc). Part K is not a relevant requirement, so if the work consists wholly of replacing a stair, it is not controlled.
If it is being altered as part of other work (an extension or structural alteration) then it should be made no worse than previously.