How to plan and budget a house renovation



To help you with your renovation budget planning journey, the team at Style Plus Renovations have put together this handy article to help guide you through the renovation budget minefield.

We’ll take you through some of the most important things you need to factor into your renovation budget plan, where to start, the project management triangle and more. Read on to take the first step towards planning your renovation.

Its the not the Destination, It's the journey.



If you’re thinking about renovating your home, renovation costs and your budget are almost certainly on your mind. Even the planning phase of a renovation will incur costs.

So, before you start laying out money in things like consents and drawings, make sure you can afford the build.

The following are a few risks that homeowners typically do not consider when they start a renovation;

  1. Not considering what you can afford to spend to avoid a budget blowout down the track.
  2. Not considering today’s building costs
  3. Not considering the likelihood of delays and the knock-on effect on your budget and project timeline.


Setting a realistic budget is the foundation of a good renovation budget in the first place. But setting one is not an easy task.

The scope and size of your renovation will have a significant impact on the cost. Start with a list of must-haves and nice-to-haves, because you’ll need to review the scope of your project at some point during planning.

Prioritising your list is a must.

A realistic budget needs to be SMART.

  • Specific – what exactly are you spending money on?
  • Measurable – how much do you need to spend on each item or stage?
  • Attainable – can you afford it?
  • Realistic – does it fit into your budget without compromising other items or stages?
  • Timely – is it the right time to renovate?


It is daunting how quickly renovation costs can mount. Furthermore, setting a realistic budget is impossible until you have detailed renovation plans, costs and quotes.

Don’t try to guess your renovation costs. If you’re planning a full home renovation or house extension, you will need plans and designs on which to get accurate quotes.

A broad cost based on average square-metre rates is not an accurate way of determining a budget. It can lead to the wrong budget value conclusion.

Architects, designers, builders, and engineers are the types of professionals you should consult during your planning stage. They can help with budget planning and keeping you on track.

The build costs will depend on a number of things, for example:

  • Materials you want to use.
  • Tradespeople you employ. Not all tradespeople are equal when it comes to finishing.
  • Quality of work, finishes and fittings you are looking for.
  • Size of the job.
  • Extensive earthworks can add significant costs to the project.
  • Location of your site. Logistics to transport your materials to the site may be a factor worth looking at.
  • For an older property, there may be additional work required outside of the renovation scope of work.


Your initial exposure to costs is typically associated with professional services such as architects, designers, Geotech specialists, surveyors, and engineers which you will consult with during your planning stage.

You will need to research the cost of each service you require for your project and budget for them. In the renovation planning process, they can quickly add up and become a significant cost that was not expected.

Additionally, council fees to process and issue a building/resource consent needs to be part of the initial cost research.

Working with a builder or a renovation company such as Style Plus Renovations during the planning and design stages is a good and practical way to keep your renovation budget under control.

Renovation companies who specialise in renovations and provide a comprehensive service from design to completion, typically have more knowledge about current construction costs than an architect. They also have a stronger incentive to get the project planned and ready to build.


Once you have defined the scope of work and the concept plans have been approved, elemental costs can be defined.

Elemental costs are defined as combined unit costs of various materials, systems, and treatments that comprise the various components of a building such as a timber framed wall. Basically, this cost plan will provide the total cost of a project divided into its elements.

This type of cost plan should also include any assumptions and exclusions agreed upon with the client. The end result will be a cost plan that provides an overview of all costs associated with the entire project.

At this point, during a review of the budget, there may be costs that have not been discussed or considered or items with a higher value than expected. This may imply compromising, which entails prioritising your must-haves and postponing your wants until later.


Detailed costing can be undertaken when the working drawings are completed and signed off by the client and are ready to be submitted to the council for building consent.

At this stage, contractors and suppliers are typically engaged to provide quotes. These quotes would be incorporated into the final cost proposal. 

Within a proposal, a recommended contingency percentage/sum would be defined. This cost reflects the potential complexities of your renovation project and the renovation building contract.

From the project management perspective of budgeting and cost planning, a concept commonly used is the Time, Cost, and Quality Triangle.

Project Budget triangle


A variation of the project management triangle that we use at Style Plus Renovations puts quality first, making a clear distinction between scope and quality.

Here the scope of work is the deliverables and specifications, but the quality has moved to the centre, so any change to any side, affects quality.

From a pragmatic point of view, it would be the project manager’s job to balance all elements in order to keep the project within budget and on deadline while still fulfilling the specifications of the project’s scope of work.

Typically, this management process starts at the planning stage when considering all the elements.

Our Project management triangle


As the saying goes, expect the unexpected during renovations. This is certainly true when renovating older properties.

A contingency sum is a sum of money allowed in the project budget for expenditure on aspects of the project that were unforeseen or unforeseeable at the time of the building contract document preparation.

The contingency sum is intended to cover the cost of unforeseen or unforeseeable work and should not be used for changes/variations or additional work.

The amount of the contingency sum will differ depending on the type of project. For example, the contingency sum in a renovation project will be higher than in a new build project.

At Style Plus Renovations, under our renovation fixed price contract, a contingency would be between 10% – 20%.


Renovations can be overwhelming for homeowners. If your renovation appears to be complicated, you may want to hire a project manager.

A good project manager will provide guidance, supervise every step of the process and help ensure that the entire renovation project stays within your budget and timeframe.


Some homeowners start a major house renovation project while holding their breath and crossing their fingers. It doesn’t need to be that way. Careful planning is the key.

Before you begin, you must know how much money you can OR want to spend on your home renovation. It is pointless to create a grand design only to discover that it will cost far more than you can afford.

Early in the planning process, consult with your bank, family/partner, and a specialist Renovation company that can offer an end-to-end service. Make sure you understand how much money you will need to achieve your goals.

Nothing is more frustrating than starting a major home renovation only to have to abandon it halfway through due to a lack of funds!

Once you know that you are OK with funding the project, now is the time to gather all of your wonderful plans and ideas that you have gathered and call in the experts. Having a clear goal in mind will help with the planning, design, and construction processes.

If you are just starting the journey, consider creating a mood/theme board with all your ideas and plans. Mood boards are an excellent way to involve the entire family in the planning process. There are plenty of options to choose from and grab inspiration, such as Pinterest.

So, on a closing note, if you hire a great designer, a good builder and a project manager who cares about your journey, you will be able to put your trust in them and relax and enjoy the process, as well as the end result!


  • What is the best way to prioritise for my renovation budget?
    Decide what you want to accomplish for your renovation. Make a list of everything you could do during your project. Mark whether you think they are Important to Have, Nice to Have, or Unnecessary next to them. This will assist you in prioritising your budget.
  • What should I focus on when I start my renovation budget?
    No matter what the scope of work is, success lies in smart planning.
  • Where do I start with costing my project?
    Your initial exposure to costs and budgeting is typically associated with professional services such as architects, designers, Geotech specialists, surveyors, and engineers which you will consult with during your planning stage. They can provide early stage indicative costs.

If you’re still undecided about what to do, contact us to discuss your renovation plans and arrange for a free consultation. At Style Plus Renovations, we help you achieve your renovation goals.

Whilst all information is considered to be true and correct at the date of publication, changes in circumstances after the time of publication may impact the accuracy of the information.

The information may change without notice and Style Plus Renovations is not in any way liable for the accuracy of any information printed and stored or in any way interpreted and used by a user.


As an Auckland North Shore family-owned and run business, Style Plus Renovations cares about what we do and we take the time to fully understand your renovation needs. We are also proud to receive some exceptional compliments from our Auckland clients.

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Tel us about your renovation project and we’ll call you back for a no-obligation chat about your ideas.

Alternatively, if you prefer, we can initially set up a meeting using Microsoft Teams or Zoom (and other meeting apps) for a no-obligation chat about your ideas.

We look forward to hearing from you to discuss your project and get you started on your renovation journey.

If you would like to know more about our renovation process, check it out here.

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