Blogs & News

Engineering and Energy Reports

Grant Jones — Sat, 21 Mar 2026 05:19:44 GMT

One of the things that we feel sets us apart as a great choice for those looking for a builder across the Canberra region, is our transparency right from the start of the process. 

Many builders will advertise a home design with a particular price, or price a custom design that is subject to change for a number of factors and will tell you that they can’t factor them in until after a contract is signed. Two of those that can have a big impact on the final construction price for a build are the engineering details and the energy efficiency rating (known as a BASIX Certificate in NSW). 

The price of the engineering or energy efficiency rating (EER) is not something that can be included in a build at a set price because they will be different for different blocks, even if the design is exactly the same. 

The engineering details will be dependent on the site classification for your block of land. A site classification is a rating based on the ground conditions of your block, specifically how reactive it is to moisture. If your block is predominantly clay it is going to be classed as highly reactive and additional measures such as thicker concrete and/or piering will be required as part of the foundations for your new home. The other end of the scale is when you have a stable site which is typically seen on rocky sites, while rock is more expensive to excavate, there is typically less concrete required in the foundations. When building in a new suburb, such as Googong, Denman Prospect or Ginninderry, the developer will typically provide the site classification for the engineer to work with. If working on an extension, knockdown rebuild or on a block as part of a smaller developer, we can organise for test pits to be drilled on your block and provide that classification. 

Engineering is also required to determine what is required as part of the structure of your home and the engineer will calculate the load in different parts of the home and the determine what materials are to be used, such as steel for lintels above openings on load bearing walls or the size of rafters for a raked ceiling. Project builders using set designs may be able to calculate and include these costs as part of the price but if you have a custom designed home, it is likely the engineering details will need to be completed before final pricing for your home can be provided. 

An EER report is required for each new build and a lot of extension projects and sets out the measures required to meet the minimum 7 star energy requirements for a home. There are a number of factors that are considered when developing the EER, including the orientation of a home and the different rooms within it, meaning that the measures required to meet the energy requirements can be different for every home. A lot of builders have a standard list of inclusions that will never meet the minimum requirements to achieve a 7 star rating, however at DJ Homes, we have things like double glazed windows as a standard and inform you of the measures you can take through the design stage to ensure you can efficiently achieve the 7 stars. 

Because these details are different for each build, they are things that should be completed and priced before you consider signing a building contract. We will obtain these through the preliminary stages of your project, with the costs covered in your pre-agreement with us and taken off the total build price if you do build with us. If you do not build with us for whatever reason, they are yours to keep and use. 

Not only do we have this work done for our clients through the preliminary stage, we also go through a comprehensive selection process that allows our clients to make all of their selections and have them priced prior to contract signing, which is something offered by few builders. By having the engineering and EER completed and priced prior to contract signing, it will help you get a full understanding of the costs involved with your build and allow you to make adjustments to the project to ensure it meets your budget. This also ensures that variations after contract signing are kept to a minimum, which takes out a lot of the stress that many go through when building with a builder that does not do this work in the pre-contract stage of a project. 

Does your builder offer custom designing without the price tag?

Grant Jones — Fri, 20 Mar 2026 06:17:04 GMT

There is a perception out there that custom designing is an expensive way to build a house, and yes for sure, there are things that can be done with a custom design that adds to costs, such as architectural features like a cathedral ceiling or by adding high end inclusions. However, custom designing can be as simple as making design choices to suit your circumstances or your block that don’t always add to construction costs. In fact, there are situations where custom designing can save money, such as getting the orientation of the rooms right, saving on the additional measures required to meet the energy efficiency requirements for a new home. 

We often have people visit our Elsey display home at Googong and ask for the construction price, only for them to then form an assumption that custom designing is expensive or that DJ Homes do not offer the value for money they require to deliver their home. There is a lot that goes into delivering a home like the Elsey, creating the cathedral ceiling with the highlight windows takes a lot of engineering and structural steel to pull off and the detail and amount of joinery all contribute to the build cost that many expect with a home that is as customised as it is, but does not mean that all aspects of custom designing comes at that price. 

Some will see an advertised price for a project home with an expectation that they can build their new home at that cost. The reality is that a lot of builders advertise a price for a home, with the knowledge that they can’t deliver the build without a lot of additional costs to cover requirements for engineering, to meet the minimum energy requirements or with an inclusion list to allow for a final occupation certificate to be obtained.

Comparing prices between builders can be very difficult to do, with different builders having a different approach to how they advertise their business and the pricing of their homes. At DJ Homes, we pride ourselves on having a comprehensive inclusion list, with items such as double glazed windows (now essential to meet minimum energy standard), blinds, laundry joinery, floor to ceiling wet area tiling and floor coverings throughout, all standard with us. On the other hand, many builders don’t and some do not even include items such as a concrete driveway, a dishwasher, wardrobe shelving or reverse cycle air-con as part of the advertised price for their homes. This means that the difference in price between a set project home design and a custom designed home, may not be down to the fact that it is customised, but purely because of the level of inclusion that is part of the price. 

So many of the benefits of custom designing do not necessarily come with an added construction cost. As mentioned earlier, getting the orientation right can go a long way to ensuring the minimum energy requirements are met without additional measures that do come with costs and means that your home is going to enjoy lots of natural light. Different rooms contribute more to the overall energy performance of a home, living areas are the most important parts of the home to get the right orientation for and then bedrooms are more important to consider than wet areas or other non-habitable spaces. 

Another key benefit of custom designing is the option to add a split level to the home to work with a sloping site. A split means that the home will sit so much better on the block, so often you will see homes have such steep driveways, either up or down, because the builder either hasn’t considered or doesn't offer split level homes. By not putting in a split, it leads to additional site costs (which are not generally included in a standard inclusions list and are not priced for the client prior to contract signing) and means that retaining walls (again that aren’t included) will be required on the site after the site works have been done. 

Custom designing also allows for the change to a design to suit your particular situation and requirements. When working with a project builder, making a simple request such as moving an internal wall a minimal amount can come with a substantial cost that means you have to compromise on what you are looking for in your new home or pay the money that means that you don’t get the value you might expect when going with a project builder. When working with DJ Homes, we will understand what your priorities are and where you are willing to compromise on your design to ensure that we get the right outcome for you and provide you great value for money. 

No matter what budget you are working with, considering a custom design home is something that should certainly be part of your planning and as Canberra’s leading custom design new home builder, DJ Homes would love to discuss your upcoming build with you.

Renovate and extend or knockdown rebuild

Grant Jones — Wed, 18 Mar 2026 06:00:52 GMT

We often visit homes right across the Canberra region where people are looking to get advice on doing a renovation and extension or a knockdown rebuild.

Many builders only offer new builds and others specialise in extension work, so they will be biased in their advice. Given that at DJ Homes, we offer both services, we feel we are well placed to offer honest advice that will help you in making the best decision for you and your home.

At times we visit homes and clients have only considered one option and not considered the alternate for a range of reasons and it is always good to discussion to pros and cons for each option to give them all the information required to make an informed decision.

We typically see a renovation being the best option when clients are looking to change the layout of the existing home with no or minimal increase to the overall size of the home. An extension is then on many occasions the best option if the layout of the existing home is to be kept largely in place and the purpose of an extension is just to add additional space.

Even when the layout of the existing home is largely kept in conjunction with an extension, if the wet areas (kitchen, laundry, bathrooms) of the home all need updating, it can see the cost of the project start to add up and mean that a knockdown rebuild is then something that should be considered.

When we have clients who are looking for a complete change to the existing home, as well as an extension to add more space, we often see this option get very close to the cost of a new build and in some cases exceed it.

Another factor that is leading to the cost of extension/renovations adding up, is the requirement for the whole of the extended home (including the existing part of the home) needing to comply with the latest energy requirements. This means that things like wall and ceiling insulation, sub-floor insulation, new cladding and new windows may all need to be considered for the existing home.

Providing estimates for a new home is something that we can do with a level of accuracy that allows people to make a decision on plans for their build. It is much more difficult to do for an extension as there are so many more factors that determine the cost of the build, that are hard to consider when providing estimates and means that you would typically need to go through the process of having full plans completed to allow for a comprehensive quote to be provided before you are able to make an educated decision on if your project will meet your budget.

The advice that we generally give is that if an extension/renovation gets to within around 20% of the cost of the knockdown rebuild project, then serious consideration needs to be given to the latter option. This is because once you get into that range, you are still going to be left with ‘old bones’ by going with the extension/renovation and the better longer term investment will likely be to have a home that doesn’t have some of the issues that older homes can have, such as water/termite damage to framing, rising damp and cladding that is not water and/or air tight.

Sometimes clients will have a preference for a renovation because they would like to live in the home while the project is being completed. If possible, we really encourage people to move out of the home, especially if there is internal work being completed to the existing home. If the work means the client is without a functioning bathroom or kitchen, then we let clients know that we don’t provide the option of them living there. The reason we encourage them to move out is because it is the best option for all involved, it makes it easier for us to manage and living in a home that is being worked on and having trades work on top of you while trying to live can cause a real disruption to family life, make it a stressful experience and in most cases mean the project will take longer to complete given we need to factor that in when scheduling the different stages of the project.  

Reading the above may seem like that a knockdown rebuild is the only option to consider, but that is certainly not the case, we still complete more extension/renovations than we do knockdown rebuilds. It is simply to highlight the instances where you weigh up the different options and when the costs get close, that is when we are likely to suggest you go with the knockdown option. As a builder that offers both options, we offer you the opportunity to have us visit your home for a consultation to discuss all options for your home.