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The advantages of a Duplex development verses a House Behind house!

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The advantages of a Duplex development verses a House Behind house!

Damon Stroud

A common question I received, is what are the advantages of a duplex development in comparison to a house behind House development. One would think it would automatically be easier to be building one home versus having to build two homes. As you will find out, it is far from the truth!

Let's look at what's required for a house behind House development.

Just so you understand what this is, a house behind House development is where the backyard is cleared a driveway is created and a new home is constructed on the rear lot. What most people don't know about this simplistic looking style development is it is far far far from simplistic!!! The problem with a house behind House development is you have an existing and typically older home that unfortunately under all counsel rules will need to be rejuvenated. The word rejuvenated sounds like doing a couple of things but in reality it can actually be an external and internal renovation. Renovating if you've never done it, is probably one of the most single testing stress bearing things you could ever do. You are dealing with tradespeople working on existing structures and hoping they don't create more damage or more mess along the way. As a general guide we budget 5 times the price to renovate something on an existing home vs a project builders price to build the same thing on a flat Sandy block. I won't go into the details but trust me renovating is never cheap unless you're prepared to stop working and become a trades-person yourself.

Completing a House Behind House

To complete a house behind house development, we need to make sure that there is enough area down the side of the existing home that meets council requirements. This is typically between 3 to 4 metres and in some cases such as the city of Belmont they require up to 6 metres. If you can't create this driveway space or you can't remove a section of the home such as a carport or verandah to make the space, then we would assess the only option is to do a duplex development as a house behind house development is not possible. Once you've drawn your house design for the rear it can be sent into the council for planning approval submission. This typically takes up to 2 to 3 months to be approved by the head planner, BUT it won't just be an approval to build a home at the back, the approval will have multiple conditions. As an example planning conditions will apply to the front existing property. Planning conditions will range from 10 to 50 items that have to be completed before you can apply for two titles. There will be conditions such as reinstating landscaping to the front, repainting the roof or even replacing the roof tiles, painting window frames or even removing some structures on the existing homes verandas. Some of our clients have even had to add a door to external walls so that there is a connection between the family room and the new outdoor area. An outdoor area, typically around 30 square metres is required for the front property as there is no space left in the backyard you will require a spot at the front to satisfy the council requirements. This courtyard to the front can't just be open to the street, it needs to be fenced with a gate and landscaped.

As you can see what looked like just building one home in your backyard, has turned into building a home in your backyard plus a full-scale renovation to the front property. Most people do not want to get involved in renovating and those that do wish they had never started. Project builders will also not get involved in renovating, it is not in their scope of works. A builders forte is rolling up to a flat Sandy block and building a structure. Yes there are builders that renovate but they are a completely different beast with completely different pricing.

Is a HBH cheaper!

There is some good news about building a house behind house that we can honestly tell you. If you choose to do this style of development it actually always does work out cheaper than having to build a brand new home at the front (duplex). Because you have an existing home with a roof with a kitchen with family rooms and bedrooms you're basically 90% there it just needs to meet council requirements.

If you're busy and work full time and have never really been involved in trade work or renovations, once you sit down with us for half an hour you'll be convinced not to even start as we have too many examples and stories we're renovating existing homes becomes cumbersome and time-consuming and potentially costlier than what you thought! The other negative of a house behind house development is if you are trying to sell off the rear home you have a 40 year old house at the front. This unfortunately sets the tone for the resale price for the rear property.

Doing a duplex development!

Ok if you've read this far you're obviously serious so congratulations, I'm about to divulge my secrets about building a duplex.

There is no denying a duplex development will cost more than a house behind House development, however I can guarantee it will be easier and you will achieve better resale.

Why duplex development is easier!

When we do a duplex development appraisal, 90% of the time we are budgeting and completing the demolition of the existing home. Because we are starting with a fresh building site with no encumbrances (such as existing houses to work around) we're able to get the perfect lot sizes to be synergistic to each other. The problem with most house behind house developments is a designer and a builder are trying to squeeze something into an area that wasn't made to put a house onto in the first place. It was designed and made as a backyard, not a building block. The design will not have to have awkward angles or extra perimeter or parapet walls. By designing a lot layout correctly for both sites we can make both homes efficient and square and better value for money.

When we submit to council a duplex proposal, both the homes are drawn, the driveways are drawn and landscaping is shown. Pretty much everything council wants to see as shown on your plans. More importantly, everything can be done by the Builder as there is no renovations. You can keep working and not worry about onsite management and workarounds and renovations of the existing house. Once you sign your contracts and pay your deposit the builder will start and finish your duplex development inclusive of landscaping and letterboxes, if you wish. It's almost no more complicated than building one home.

Will a duplex development give me better resale in comparison to a house behind House development!

The answer to this is simple but sometimes the questions are more complicated than the answers. If I was to drive you down the street and show you a brand new home with a street frontage, and then showed you a 40 year old home that has had a busy bee tizzy up, you know what you would go for if you're in the market to buy. There's some amazing facts in real estate when you look into things. One of those facts is 90% of property sales are established property. Approximately 10% of real estate transactions are construction. The general public unfortunately would rather buy an established property because building can be painful and time-consuming and have hidden costs. Secret number one, when you build a brand new home and present it to the established market place, people will flock to it. Why, the home has a builders structural warranty, appliances have manufacturer warranties, the home is not been lived in, it has 6 star energy efficiency requirements and potentially acoustic requirements making the home quieter to live in. The design may have things such as 5 mm glass to contain heating and cooling. It can have the latest air conditioning and heating systems and better insulation. More importantly under new R-code rules, the yard area will be to the due north to catch winter sunshine and light.

The design will be a modern design. A very popular and practical trend we have seen over the last five years, is increased walk in pantries that can accommodate appliances such as coffee machines and mixers. I could go on and on, but you understand what I'm saying here, it's a new home and a new home gets better resale!

Other duplex advantages –

  • Maintenance

  • Greater tax advantages

  • Modern design

  • Modern construction techniques

  • Better block layouts (not constrained)

  • Save time, energy and stress