Custom Home Renovation and Extension Specialists

Hidden costs that may be missing from your builder's quote

When reviewing formal building proposals/quotes from various builders, it is vital you ensure that everything that you would expect to be included in the proposal is included. Ensuring that your proposal is detailed will ensure that you are not surprised by hidden costs throughout the process of your build.

Building can be a new and often daunting process to a lot of people are not familiar with the industry and do not speak ‘builder’s language.’ So how can you be sure that the quote that the builder has given you includes everything that it should or in fact is actually missing items?

When it comes to choosing the right builder, it is best to make informed decisions. And to do this you can arm yourself with useful information by reading this blog and discovering the 12 items that are often missing from your builder’s proposal.

You would expect a detailed final proposal from a professional builder to be at least 30 pages long with every detail clearly described and accounted for. Anything less than this, then you can expect that there will be items missing and you may get caught out along the way.

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1.Council Fees

The cost for approvals can vary depending on where you are building and the size of your new home renovation and extension. Approval fees are usually paid to Council or a private certifier. These fees can be made up of Development Application (DA) Fees, Building Approval Fees and Construction Certificate (CC). There are many other fees that are also included such as Long Service Leave Levy, Archiving and Filing Fees. Best to check with the builder to ensure that ALL of the necessary fees have been covered.

2.Site costs

To ensure that accurate site costs have been included in your formal quote, it is important that the builder has paid a visit to your site. To be given an accurate indication of how much it will cost to prepare your site for construction, the builder needs to factor in the service locations, the slope of the land, and the design of your home as well as the classification of the soil. Best to ask the builder if they have included a generic provisional sum amount or are the costs specific to your own site.

3.Site amenities

It is a requirement that every building site has a portable toilet, erosion control barrier as well as a temporary site fence. Some builders may try to claim these as variations during the build. Slack builders have been known to force their tradesmen to use your toilet and the builder pockets the savings!!!

4.Structural costs

Depending on the design of your new home, the structural requirements of the build can vary. So, the more complex your design, the more structural requirements needed and the higher these costs can be. These requirements can include reinforcing steel, slab design and structural timber beams and these are often not determined until the completion of engineering plans. Ask the question – have you included the cost for engineer drawings? Has a sum been allowed for in the quote for structural requirements? A good tip to ensure that your structural requirements have been accurately included in your formal proposal is to have the builder source engineer’s drawings prior to signing any contract. A cost will be involved in these plans to be done, but it can give you peace of mind and actually save you money in the long run.

5.Energy Efficiency requirements

Every new home extension and build is required to have an Energy Efficiency report. This is an assessment by a certified practitioner that assesses the design and calculates how efficient the design is in regards to ventilation, glazing, eaves overhangs and thermal insulation and the like.

6.Wall tiles

Of course, wall tiles will more than likely be allowed for in your proposal, but the height in which they are laid needs to be clearly documented. This is an area that builders will try to save money by not clearly indicated in the quote the height of the wet area tiles. If you are expecting floor to ceiling height tiles in the bathrooms, then check that this has been allowed.


Every wardrobe requires shelving, it is pretty useless otherwise. Wardrobe fit-outs can vary so much depending on how it is to be used. If you are expecting open shelving, drawers, long and short hanging spaces then it is important for your peace of mind to make sure that these specifications are clearly itemised.

8.Electrical provisions

There are so many costs that relate to electrical items when building, renovating and extending a home. Your proposal should include an adequate number of light points, light switches, power points, data points and more. This is an area where builders can try to skimp and save and surprise you with hidden costs once you realise that two light points in your living room are not enough to provide adequate light, and ‘single’ power points are often installed.

9.Bathroom accessories

To finish off each bathroom, a number of additional accessories are required. These include items like mirrors, towel rails, and toilet roll holders. If you are expecting matching accessories of a high standard, then ensure these are catered for in your proposal.


Flyscreens are something that is often missed in the building quote. If unsure, ask the question…

11.Outdoor taps and gas provisions

You may have in mind how many taps and gas points you will need in your new home. Then ask the builder outright, “How many have you allowed for?” Will these be enough to meet your needs?


To make an informed decision, ask the builder outright what is excluded from the building proposal. This will indicate to you items that you might have been expecting and that you may need to have included in order to move forward.

To discover more questions to ask a builder before signing a building contract, download our free guide on our home page. It’s the essential guide for consumers who want to avoid becoming another building industry victim…


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