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August 14 2019

Thinking of building your own home? Why you MUST design your own floor plan.

Gemma Broomfield
Interior Design

I have something to admit. I got into designing homes for our projects because the designers we hired never seemed to quite understand what we wanted. We’d often end up drawing outlines for them by hand or in SketchUp.

But I realised something recently – it was my fault that the expectations I placed on our designers were not met the first time round and cost us more money. They aren’t mind readers! For example, have you ever wanted your partner to do something, like do the dishes, but failed to ask them to do it? They should just KNOW that it should be done, right? WRONG.

It’s the same with your designer. If you’re going to hire an architect or building designer to come up with a floor plan you’ll love living in for the next 10 or 20 years, you cannot afford to just tell them you want a three-bedroom, two-bathroom home for under $400,000. They don’t know you or how you live.

Some of the tools I outline below designers already use, but thinking about this and presenting to them before you even get quotes will save you tons of money and ultimately provide you with a home design that’s an extension of how you like to live your life.

1. Who will live in the home?

Is it just you and your partner or do you have children? Don’t just think about the current household, but the future household too. Are you planning on having children? How many? Are your teenage children going to move out of home in the next year? Do you have a parent that may move in with you soon?

2. Design for how you live 95% of the time, not 5%

I’ve designed a few one-bedroom apartments now, and there’s always a debate in the office about whether I should include an ensuite to the bedroom plus a toilet for guests, or turf the powder room and have a bigger kitchen/living area?

The answer is that it does depend – it depends on how often you have guests. If it’s once a week you have guests, say for 4 or 5 hours, that’s only 3% of the week!

So, I say stuff it, guests can walk through the bedroom to the ensuite, plus it’s a good idea to make your bed and clean your bathroom at least once a week anyway!

My point is, don’t sacrifice on space or layout because you may have something that happens only 5% of the time. Design for you, not your guests or that parent that visits only once or twice a year.

3. Audit your time

How do you spend your evenings and weekends?

Do you spend a good two hours in the kitchen each evening? Or do you like to curl up in an armchair and read a good book with a cup of tea? Do you sit in front of the TV most nights, or do you spend time with your family, chatting the night away at the dining table with a bottle of red?

Do you spend lots of time in the garden? Do you have lots of barbeques in the summer? Do you entertain and have guests over often? Do your kids play outside or make a massive amount of mess with toys and games inside (ie. give them a playroom!!)? Do you like to tinker around in the garage with your bike or car or work on weekend welding projects?

Make sure you put an estimate of hours on each activity, because this will ultimately dictate their importance and priority.

4. Complete a Spatial Interaction Matrix chart

Once you’ve worked out the spaces you think you’ll need, create a Spatial Interaction Matrix chart. Write the spaces down the left column. These rows then dip on a 45-degree angle and meet all the other spaces in the house. You should put a tick, star, dash or cross in each box. Tick if you’d like these spaces to interact, star if they don’t have to immediately interact but be close to one another, dash if it’s not necessary for them to interact and a crossif you do not want them to interact. For example, it might be useful if the laundry and garage interact, so this might be a tick or star. But it’s probably not important that your master bedroom interact with your garage, so you might put a dash or even a cross here.

See an example of one I’ve completed below and click here to download a template.

5. Work out room sizes

Once you’ve completed the matrix, work out what room sizes you’d like. Base this on your current home to get an idea for what you think is too small, unnecessarily big and just right. If a room is 4m x 4m, write 16m² here.

6. Create a bubble diagram

This activity is not mandatory, but it can be pretty fun. You’ll likely need several sheets of paper for this to refine the zones. The idea is to use what you’ve written in the matrix and draw circles overlapping for each area, roughly in size proportion. For example, if you wanted your living room and kitchen to interact, you may draw your kitchen circle in the middle of the page, and then the lounge circle overlapping as a larger circle. If you find this idea a bit daunting, your architect or designer can do this for you before they start drawing up concepts, to ensure they understand your requirements. Don’t worry too much about orientation, passive design or external design of the home – this is a task that should be done by your designer.

7. Create a Pinterest board

Add floor plans you like (make sure you do this after you’ve done your matrix so your saved layouts are more focused). Make private comments on what you like about each floor plan and what you don’t, so your designer can see this.

8. Audit your belongings

Have a think about what you own currently, and what you may like to have in your new home if you’re buying any new furniture. Book or music collections, toy storage or clothes storage requirements are good to think about. You want to design a home that has a place for everything you treasure and use. They should be located conveniently. Measure your furniture and check your matrix still works.

9. What is your budget?

You might be thinking, goddamn it, why didn’t you put this first??? There’s a reason. The exploration above will likely have absolutely everything your dream home could have in it. The point here is to work out what size home you can afford so that you can prioritise a big wish list into a realistic plan of the most important things based on how you live.

A great tool for working out the cost of your home if you’re not already talking to a builder is the BMT construction cost calculator.


- Add extra square metres on top of the spaces you’ve added up for things like hallways and entry ways.

- Include any external entertaining areas and paved landscaping areas

- The amounts in the calculator exclude GST, so you will need to take this figure and multiply it by 1.10 for a total estimate of what you’d have to pay.

- Add 5% for walls and other extras

10. Refine your matrix based on your findings here in relation to your budget.

Once you’ve gone through this process, you’re fully prepared and ready to get some quotes with a building designer and architect!

I hope this article has helped you work out what you want in your home.