As a Registered Housebuilder under the voluntary scheme, houses were inspected during building, buyers were covered by a 2 year warranty against major defects, and against the insolvency of the builder. By 1963 26% of all housing was built by Registered Housebuilders.
1967 saw the upgrading of the NHBRC's standards, particularly in the provision of power outlets, kitchen design and space heating, drawing on the recommendations of the Parker Morris Committee. By the end of 1970 92% of new homes were built by NHBRC members.
Under the Building Act 1984 the NHBC set up a subsidiary company (NHBC Building Control Services Ltd) to became an approved inspector for verifying that buildings were built in accordance to the UK's national building regulations.