Sometimes the work of the contractor is not of good quality and it is discovered either by the homeowner themself, by a building inspector or a third party. This can create a difficult situation. If the work is being reviewed by a municipal inspector then specific deficiencies may be identified and their remediation monitored and reviewed by the same inspector. However, in situations where there is no such inspection (and not all work requires municipal inspections) then a homeowner may need to call in another contractor or a specialist.
If the contractor’s work is found to be deficient then technically the contractor has the first to remedy it unless the deficiency is of such an extreme nature that it constitutes a material breach of the contract. If it is not a material breach and the contractor can and does remedy the deficiency then all is well and good. It is only in situations where the contractor refuses to remedy the deficiency or it is a material breach that serious problems arise.
In situations where it is not a material breach and the contractor refuses to remedy it then this should be documented in writing. Specifically, the deficiency should be identified and a deadline for remediation should be set failing which another contractor will be hired to undertake the work and any extra costs will be borne by the initial contractor.
In situations of a material breach the problem should be identified and explained by way of another contractor, expert or engineer and a demand for any additional costs made (or at least have the contractor put on notice for them if they are not readily known at the time).