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What to know when building a duplex

If you’re thinking of embarking on a duplex journey then my biased opinion is, do it!

Building a duplex could be the opportunity for you to make a nice profit or allow yourself to build a beautiful new home by selling one half in order to pay off building costs and draw down on your mortgage. Depending on the rental return in your area it could also act as fantastic investment to hold onto.

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After just completing our first duplex project it’s safe to say lessons were learnt, but overall it was a very enjoyable and successful experience that hopefully we will do again one day.

Here are the three biggest lessons from our duplex build:

Identify an area with the right return

We had lived in Maroubra for about six years however, because Luke and I spent so much time online looking at property, we often scrolled through recent sales from all areas that surrounded us. Luke claims it was him (although I believe it was me) who noticed that duplexes in Matraville were selling for quite a premium price in comparison to what old homes on large parcels of land were going for.

We crunched the numbers quite simply:

Land cost + stamp duty + design/building cost (a lot of guesstimating) + estimated interest for the duration of the build + agency fees to sell

I then put together a spreadsheet of all the duplexes sold in the area and worked off what the return would be based off the selling cost of the lower-priced duplex sales. Of course the competitive streak in us hoped we would achieve the result of the higher market sales but we did this to play it safe and make sure it was still worth it.

We also forecasted in the event we could not sell one side of the duplex (hello Covid!) what the rental return would be and if this could cover or come close to the mortgage repayments.

All of our numbers matched up so we decided to take the leap and start looking for our duplex site.

Luke Parker and Kate Lawrence reveal their finished duplex build. Picture: Alan Richardson

Finding the right block

As we were rookies to the building game, we knew the block we bought had to be flat for ease of building and to reduce building costs. We did our research with the council around zoning and what dimensions were required for the property frontage and land size. Another tip is to look out for easements as this can significantly add to the building cost or hinder design capabilities.

Once we had a good understanding of this we began our property search and not too long into the piece secured our beautiful home.

Top tip: Before purchasing your block try to negotiate a longer settlement period so that you can use this time wisely and start your house design while you’re not paying interest. We had a 90 day settlement and submitted our DA to council nearly as soon as the house settled.

We also lived in the old house for just over six months while our DA was being approved, this saved us from doubling up on rent and mortgage repayments. Although we didn’t have an oven for six months and a few cold showers the savings were definitely worth it.

The block size and shape allowed for pools in both properties. Picture: Alan Richardson

Design for your needs

When it comes time to the design of your duplex firstly decide what they will be used for – i.e future home or investment property. We always intended to keep one side and sell the other and this helped me make a lot of interior selections on my house vs the investment.

In our house we ran black timber veneer cabinetry through the entire home and experimented with different products, using venetian plaster in the bathrooms and a slightly more expensive hand cut Moroccan tile. This style is definitely Luke and my flavour but isn’t for everyone.

In the investment house we played it safe and stuck with light colours which appeals to a broader market. I opted for a white and timber kitchen and neutral colours in the bathrooms. It is a very pretty colour palette which runs throughout and I believe a lot of people could inject their own sense of style through soft furnishings.

Kate and Luke in their new kitchen. Picture: Alan Richardson

The facade was something I knew was extremely important as a house’s street presence leaves people remembering and talking about your home. We engaged an architect, Arkhaus, who had designed many duplexes in the area, all of which had sold for record prices. This was something I was happy to invest in as I believed we would see the return and I had a lot of trust in what he would create for us.

Designing a duplex is different to designing a freestanding home so engage someone who can prove they know what they are doing, as maximising your space and light in the home is very important.

Top Tip: Engage a builder early in the design piece as their knowledge is extremely important and can save you a lot of money when the construction actually starts. They are the one building the house so their involvement during design makes total sense particularly if this is an investment.

My builder TrueBuild Homes was a saving grace. They knew we didn’t want to over capitalise and came up with many building solutions that enabled us to build a beautiful home without completely blowing the budget.

The architectural light void floods the space with natural light and makes for an interesting feature.

Lastly, some food for thought:

– If your block allows, think about what walls in the house will join with your neighbours. I personally didn’t want any bedrooms joining so our staircase became the only common wall.

– Make sure you’re aware of what direction your block is facing so both sides of the duplex will get their time in the sun.

– Understand all council regulations about building a duplex in your area before purchasing a property.

– Research previous sales in the area on what will achieve a premium price. Eg. adding a pool, 5th bedroom, or second living area.

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