Defects are dealt with differently depending on whether they are identified during the construction period or after (sometimes considerably after) the certificate of practical completion or certificate of making good defects have been issued. They may also be dealt with differently depending on whether the contract specifically defines what a 'defect' is.
Defects should always be brought to the attention of the contractor as soon as possible, preferably in writing to enable resolution in the most efficient and practical way. While the contract is being performed, the contractor may be incentivised to remedy defects through the withholding of a contractually agreed retention sum or through the payment application process under the contract. Whether or not it is appropriate to issue a 'pay less' notice should be considered.
Following the issue of the defects certificate however, the employer’s hold is loosened but the employer still retains the ability to pursue the contractor through a breach of contract claim or in limited circumstances a claim in tort or possibly the Defective Premises Act 1972.