- 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.
HOUSE EXTENSION RENOVATIONS COSTS CALCULATOR
COST OF A HOUSE EXTENSION | House Extension Renovations Costs Calculator 2023
Are you considering a house extension renovation?
Before you start, you’ll need to get a good idea of the costs involved.
A single-story house extension in Auckland, NZ can vary widely based on a number of factors. These include the size of the extension, the quality of the materials used, the complexity of the design, labour costs, and any site-specific considerations. Construction costs can also be influenced by economic conditions and fluctuations in the building industry.
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.
Also, if you are looking at building upwards, a second-story extension is 50% more than a ground-floor extension.
Keep in mind that this estimate does not include additional costs such as design and architectural fees, council consent fees, utility connections, kitchen, laundry, and bathrooms.
To learn more about house extension renovation costs check out our article here.
Style Plus Renovations North Shore has created a house extension renovations costs calculator to provide homeowners with an indicative estimate.
With this calculator, you can plan your budget and make sure you don’t overspend.
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THINGS TO THINK ABOUT FOR A house extension RENOVATION IN NZ
There is no set formula for calculating the exact house extension costs, every home renovation project is unique.
The following are common 3 factors to consider when investigating your house extension costs in 2023:
1. How much extra m2 space do you need?
Whether you are looking to improve your lifestyle, increase the value of your home or are intending to update the interior style and exterior of your home, when estimating costs it is best to get a rough idea of just how much space (m2) you will need.
2. What is the functionality of the extra space you want to build?
The intended use of the extension will guide the required space. If it’s a kitchen extension, for example, you’d need to consider the counter space, appliances, and dining area. A bathroom extension would need to account for fixtures and enough space for comfortable use.
Both bathroom or kitchen, this will increase your costs, as these rooms are the most expensive to build. This is due to the plumbing work, gas and piping installation costs, as well as any appliances and fittings required.
Adding any of the following will increase your house extension budget:
- Adding a mid-range bathroom or ensuite will add between $30,000 – $50,000 to your price,
- Adding a mid-range kitchen ranges between $30,000 – $50,000.
- Adding a laundry can add between $6,000 – $18,000 to your project cost.
3. What kind of land are you building on?
Is your property on a flat, sloping block of land? These are factors that will impact your build cost.
You may also need to consider the following;
- If there is any demolition work that needs to be undertaken before building the extension.
- If there is any excavation work to be undertaken.
- If there is any hazardous material that needs to be removed i.e. asbestos.
These are all elements that can add to your renovation cost.
THERE IS NO ONE SIZE FITS ALL
In conclusion, there is no one size fits all answer to how much extra m2 space you will need for a house extension. Typically, it depends on your specific circumstances and requirements.
To get an accurate estimate, it’s recommended to consult with an architect or a professional renovation company such as Style Plus Renovations that can assess your current home, your goals, and local regulations to determine the ideal size for your extension.
HOUSE EXTENSION RENOVATIONS COSTS CALCULATOR FAQS
HOUSE EXTENSION RENOVATIONS COST CALCULATOR
This House Extension Renovations Costs Calculator is aligned with current 2023 market prices for materials and labour and is intended to provide you with a general idea of the potential investment based on the information you provide.
Please keep in mind, that additional cost variables such as design and architectural fees, council consent fees, utility connections, kitchen, laundry, and bathrooms can influence the overall project cost.
When you have completed the kitchen renovation details, click the ‘NEXT’ button, enter your contact details, then enter the code, and finally click on the ‘SEND’ button.
We will review your House Extension Renovations Costs Calculator request and get back to you within 5 working days.
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Tip: It’s important to invest in quality fittings and fixtures for your home renovation, especially for regularly used products that can sustain the usual wear and tear. The bottom line is, ‘it pays to invest in quality products’.
Average architect fees applied
Average engineers fees applied
Average site insurance fees applied
Contingency set at an average of 15%
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Cost set at mid-range bathroom
Cost set at mid-range kitchen
The cost of adding a laundry room can differ considerably, influenced by factors like the room’s size, the extent of necessary renovations, and the quality of materials/fittings..