Two separate approvals
Land use rights (zoning, consent, title) decide what you may use a property for and how much you may build. Building plans, approved under the National Building Regulations, decide whether a specific structure is safe and compliant.
Order matters
Get the land use right first. The City's building control will not approve plans that exceed the zoning controls or conflict with title conditions.
When selling
Missing plans for a carport, lapa or room can hold up a SPLUMA clearance. Fix them before listing.
General guidance only. Rules change and every property is different — get advice on your own erf before acting.