How to Manage Your Home Extension Budget +7 Ways to Reduce Extension Costs

Most of the time a renovation or a home extension is a much better investment than buying a new property and moving. However, like with every construction project, keeping your expenses in check can be tricky and there’s always a risk of something unexpected blowing up your budget even more. So today, let’s talk about how to prepare your wallet for home extension costs and avoid blowouts.

Second Storey House extension frame

Categories For Your Extension Budget

The first step in controlling your construction budget is meticulous planning. The most common sources of “unexpected” expenses aren’t on-site accidents or any sudden developments in your project – a much more common cause are things that simply slipped your mind during initial budgeting or that you didn’t know the prices of. So, start by categorising the biggest costs – like site groundworks, exterior and interior costs – and then breaking them down into subgroups for smaller expenses. Or you can talk with your builder to arrange all the main costs chronologically. It helps to use spreadsheets to keep track of your costs and totals.

Hidden Extension Costs

Getting a detailed quote from your builder is generally the best way to have a reliable budget estimate, but there are some hidden dangers there too. For starters, some builders tend to underestimate the costs to get you to sign up with them. By the time those underestimations catch up with you blowing your budget you’ll be well into your construction project and would hardly switch builders midway. Make sure your builder is trustworthy and has a good track record of finishing jobs without budget blowouts. Additionally, if you are comparing quotes from different builders, look for provisional sums and prime cost items. These are expenses that can’t be accurately estimated early on, so the builders just set aside a certain sum for them. If you see a significant difference in those estimates between different builders, it is likely that one of them is low-balling those costs and you may be in for a nasty surprise later down the road.

Research to Reduce Extension Costs

Market research will also help you find the best available prices or at least know which prices to expect. If you start your research well ahead of time, you may even be able to catch a few bargains on items such as appliances and light fittings by tracking the prices and stocking up on some things early.


All preparations aside, though, it is very unlikely that your project will go exactly as planned. Construction requires a lot of coordination between different professionals, delivery schedules, times of day and even weather conditions. Odds are, you will hit a few bumps in the road here and there. That’s why you need contingency funds for your project. Taking out short-term loans to cover additional expenses is a lot harder on your wallet than saving up in advance.

Track All Your Home Extension Costs

Another thing that can lead to budget blowout is the “scope creep”. That means incremental expenses that seem small and insignificant at first – a couple hundred here or there – that add up to quite a sum over time. Always plug all additional spending into your budget, no matter how insignificant the price may be. That way the expenses won’t creep up on you halfway into your home extension.

Step By Step Building Guide book blue

7 Ways to Reduce Extension Costs

Building an extension can be a great opportunity to increase your home’s size and value at a much lower cost than buying and moving to a new property. However, extending your home is still a rather costly endeavour that can eat away at your budget, not to mention that some rookie mistakes may end up blowing up your expenses. Today we’re looking at 7 different ways to shave off extra spending that will help you keep your extension well within your budget.

1. Simplify Your Design

Cost-efficiency starts with a simple and effective building plan. First, scout out the ground for your extension – demolishing old constructions, removing tree roots and evening out any inclines can add some unexpected expenses, so make sure you choose a reasonably clear area for a ground floor extension or consider going for a second storey extension instead!

Second, adding corners or curves racks up your extension costs without adding much space or value, so avoid complex and extravagant designs. Simple rectangular shapes with a pitched or flat roof would serve you best.

Lastly, be sure to consider and plan out the location of all the necessary utilities – from taps to power points. Consult with your builder to get the most energy-efficient layout. It will save you a lot of time and money down the line and spare you the trouble of having to re-do some of the works later just because you haven’t laid down some piping.

2. Plan Ahead

Create a detailed schedule for your project with your Melbourne extension builder and write down a budget that accounts even for the smallest expenses like light fittings and slipcovers. While it’s unlikely that you’d be able to follow your plan to the letter, detailed estimations will serve as guardrails for your project, preventing it from getting out of control. Plus, giving yourself enough time to conceptualise and itemise your design means you’ll have a better chance to anticipate and prevent any potential problems with the build.

A schedule is even more important when setting the timing for your deliveries. Wasted labour costs can be devastating to your budget, so make sure you have all the necessary materials at hand for the tradespeople.

3. Choose Ready-Made Solutions

When working on your building plan, make sure your design relies on off-the-shelf products rather than requiring too many custom-made elements. That includes sticking with standard-size doors and windows wherever possible and readily-available materials such as concrete, bricks and timber.

4. Measure Twice, Cut Once

Avoid wasting materials by always knowing precise measurements for every part of your extension. Make sure to measure everything on-site and keep your plans accurate and properly scaled. That way you won’t run into any nasty surprises down the line – like finding out you don’t have enough materials or that your doors don’t fit in the frames you’ve made. Also, factor in the distance between the furniture into your design plan and make sure you have enough room to fully open doors and drawers and reach different parts of your extended home without having to move sofas and armchairs.

It is also important to find the right balance when it comes to stocking up on materials. Over-ordering is very wasteful and will eat up your budget quickly if you are not careful. However, falling short means a greater risk as delays and extra delivery charges may hurt your wallet even worse. By the time you realise that you need more materials, the design you have previously bought might already be out of stock.

5. Recycle and Reuse

 Reduce Extension Costs By Recycling

If you have some leftover materials, it might make more sense to try to sell or re-purpose them, rather than throwing them away. Some recycling facilities would even pay you for your materials, so check for them before getting rid of leftovers. Even if you only have a few bits here and there – like a few unused tiles and a bag of glue – you can use them in a variety of DIY projects from home improvements to fun decorations to make together with your kids.

Purchasing reclaimed materials for your project can also save you a good chunk of change, in addition to being environmentally-friendly. Check out your local salvage yards and second-hand stores to find discounted recycled building components or to sell off your own old materials!

6. Trade Discounts

The key to getting the best discounts is assertiveness. Don’t feel shy asking for a bargain and don’t give up too easily. Check if there are any discounts for paying in cash (just don’t forget the receipt!) or if the supplier has any end-of-line deals. Also, don’t chase after famous brands when purchasing supplies. Instead, look for cheaper equivalents from less known companies and compare product reviews online before committing.

7. Find the Right Builder

Entrusting your project to an inexperienced or untrustworthy builder can undo all your best efforts of creating a cost-efficient and functional home extension. Always check your builder’s certifications and references and be wary of those who offer unrealistically low prices or work without a contract. Such “cowboy builders” may end up costing you a lot more than even the most overpaid professionals due to low-quality workmanship and shady business practices.

Instead, look for a builder with a lot of experience and an impeccable reputation who can also think on their feet and find budget-friendly solutions to any problems that may arise during the construction. Organisational skills, good communication and professionalism don’t just make for a better building experience, they come with a quality guarantee that will save you a lot of trouble in the long run.




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