Use the free deck building cost estimator to get an instant ballpark idea of how much it costs to build a deck house in New Zealand. figure for your home renovation or maintenance project. We've used real data sourced from real tradies using Builderscrack to calculate the estimates. How much does it cost to build a deck? Refresh puts together tips on different materials and their costs for building your new deck. How much does a house extension cost in New Zealand? back to estimates list. ARTICLE Stephanie Matheson.