The Employer's entitlement to recover costs in respect of Defects are stated at clause 45.1. The right to do so depends firstly on the Contractor having been given access to correct a notified Defect but not having done so within the defect correction period. In this case the PM has the right to assess the cost to the Employer of having it corrected by other people and the Contractor is obliged to pay this amount.
However it doesn't sound like the Defect has been corrected by other people, the leaking wall is still leaking and is still defective. This said much will turn on the technical aspect of this and a detailed analysis of what the Contractor's obligations were in the contract, and why the wall is leaking ( I speak from personal experience of seeing expert witnesses argue about this point).
You could use clause 44 and propose that the Defect isn't corrected and get the Contractor to submit a quotation for this. Note here though the PM does not have the right to assess if the Employer isn't happy with the quotation.
However it doesn't sound like the Defect has been corrected by other people, the leaking wall is still leaking and is still defective. This said much will turn on the technical aspect of this and a detailed analysis of what the Contractor's obligations were in the contract, and why the wall is leaking ( I speak from personal experience of seeing expert witnesses argue about this point).
You could use clause 44 and propose that the Defect isn't corrected and get the Contractor to submit a quotation for this. Note here though the PM does not have the right to assess if the Employer isn't happy with the quotation.