A Christchurch Licensed Building Practitioner (LBP) has had his licence cancelled for two years after he overcharged a client by $100,000.

Ronald Carmichael was found to have committed work negligence and incompetence by the Building Practitioners Board, after he gave a quote for a build which was incorrect, pushing costs $100,000 above the contract price.

The board said Carmichael was negligent in failing to correctly read and interpret the plans and to price the project accurately.

Carmichael also failed to keep the homeowner informed and allegedly tended to treat her assumed ability to pay as an open chequebook.

"Understanding your regulatory and contractual obligations is important, and has been highlighted by this complaint. Ensuring that there is a written contract and the required documents are provided before starting building work is required by law.

"It helps to protect both LBPs and clients, and can make everyone's life a lot easier down the line if a dispute were to arise.

"This is a reminder to LBPs that being honest on your licence application and in your business decisions is important – not only for your reputation and that of your business, but also to maintain your license," said Paul Hobbs, Registrar, Building Practitioner Licensing.

The board also said Carmichael failed to disclose and sign a contract between himself and the client.