- How do you calculate extension costs?House extension costs are typically broken down and aligned with four key areas:
- Preliminaries - These have costs which are based on the complexity of the site and the location of the work.
- Structure - A house extension involves adding a structure to an existing level either sideways, towards the back, to the front, or going upwards. The extension may have any combinations of a bathroom, kitchen, laundry
- Envelope - The building envelope costs includes all costs associated with layers that separate the interior from the exterior of the building. For example, the external walls, doors, windows, roof type of the building.
- Finishes - Projected costs for the fittings and finishes based on quality.
- What is the most expensive part of building an extension?The most expensive structural part of building an extension are the foundations (civil works) and roofing.
- How much does it cost to add an extension to a house NZ?On average, you might expect to pay anywhere from NZD $3,500 to $5,500 m2 for a basic house extension. However, this is a rough estimate and the actual cost could fall outside of this range. Typically, a 36m2 ground floor extension will cost between $126,000 to $198,000. There are a few factors that will affect your total costs, such as the quality of your inclusions and chosen construction.
- What is the House Extension Renovations Costs Calculator?We've created this calculator for house extension costs to provide a rough estimate for those who are conducting an initial research. The calculated costs are derived from the average expenses associated with renovation and extension projects in Auckland. It's important to note that every house has its own distinct construction, materials, and site factors. As a result, the estimates provided by this calculator are approximate and should not be treated as a formal quotation.