Inherent defects and the repair covenant in commercial leases

Abstract

Does the covenant to repair in a commercial lease include an obligation to put right an inherent defect in the building, if that inherent defect causes the building concerned to fall into a state of disrepair? Or is it the case that, whoever bears the obligation of repair under the relevant covenant, that person need only remove the damage caused by the inherent defect, without removing that inherent defect itself? What happens if the only way the damage can be remedied is by removing the inherent defect? Does such work still constitute ‘repair’, or does it amount to ‘renewal’ and so fall outside the repair covenant?