Sustainable House Design Guide

A Step-by-step Guide

Here’s a sustainable home design guide I wish I’d had before I started on the ImPossible House. Hopefully, these steps will save you time, money and stress in your own build. I’m including information about how not to get conned by “sustainability experts”, what type of experts you need and how to quickly identify if the expert is the right person for the job, as these are the things that have cost me the most money and caused the most headaches!

Step 1: Define your objective

a) Explain exactly what you mean by living sustainably. Do you mean going off grid completely or something else? This is important because it helps your planner, architect and other people involved in the project understand exactly what is required of them. It also means that the final product will align with what you, the client, actually want. (No tears or arguments at the conclusion of the project.)

b) You can use the requirements in my factsheet as a starting point for deciding what you might want.

c) Make sure your goals are understood and agreed to by your team (solar expert, planner, architect, builder, designer, water expert etc.). Ask each contractor to include your objectives in any contract that you sign.

Step 2: Determine your requirements before you engage anyone

Determine your approximate requirements and goals for going off the grid BEFORE you engage the planner and architect and before you define your budget.

It was a HUGE oversight of mine not to gather this information upfront. Not establishing my water, energy, recycling and harvesting requirements prior to engaging with the architect and planner led to significant costs.

If you are going off the grid for water and energy, talk to the solar and water recycling experts BEFORE you start talking to your architect and planner. In my case, I learned the hard way that going off grid requires a lot of space! (it seems so obvious now!). It’s this information that the architect and planner need before they can start helping you with the building envelope.

Once you’ve figured out which sustainability features you require, ask your architect to design the building around your off-grid solution. If sustainability is a secondary goal or you aren’t making changes to the building, then this obviously doesn’t apply.

Sustainable House Guide – Hot Tip

Order of engagement

If sustainability IS your primary objective, engage your experts in this order:

1. Water specialist
2. Solar specialist
3. Planner
4. Architect
5. Thermal performance assessor

Make sure they all know what each other is proposing. The solutions need to work together! There will be a lot of to-ing and fro-ing between all the project team members, but in my opinion it is better to fit the house design around your living requirements than the other way around.

Step 3: Choose the right people

This is possibly the most important part!

There are lots and lots of planners, architects, solar installers and sustainability experts out there touting their services. Not all of them will appreciate your goals or help you do things that are out of the ordinary. So make sure you define your goals prior to engaging them and communicate with them clearly from the outset.

In general, you want the type of people who say, “that sounds difficult, but let me think about it”, instead of “no, that won’t work, it’s impossible” or “that will be too expensive”. I think most of the time, when people say these things, they are trying to sell you the cookie-cutter solution and save themselves time. You don’t want these people! You want creative people who are passionate about sustainability and, importantly, will be there to support you if any part of their solution goes wrong further down the track.

Sustainable House Guide – Hot Tip

How To Not Pick a Con Artist

I think it’s fair to say that we will all get ripped off at some stage during our lifetime, and on big projects like renovations there’s scope to lose a lot of money. So here are my tips to avoid being conned:

1. Ask for references and call the referees!

2. If they claim to be a sustainability expert, visit their house to see if they’re walking the walk. If the house is run down and their systems are in disrepair, then they aren’t the right person for the job. If they don’t look after their own house, then they won’t care about yours.

3. Immediately fire anyone who suggests that you start fights with the council or encourages you to break the law or hide things in your development application.

4. Ask me about my experiences. I’m more than happy to have a chat!


1. A planner. A planner will help guide you through the council rules and regulations, help you understand the order of things with respect to the development application and provide you with a design envelope that you can give to your architect. They will mitigate the risk of submitting plans to the council which are likely to be rejected, saving you resubmission costs. NB. The cost to submit and get drawings re-done is considerably more than the cost of a planner. Not having to keep asking your architect to re-do the drawings will save you time as well – and time is money.

2. An architect who is genuinely interested in sustainability and who has runs on the board. Many of the architects I engaged were more interested in designing grandiose buildings than incorporating sustainable features. Many of the architects would push back on my ideas and try to reduce the scope of my ideas.

3. A solar expert who won’t fob you off whenever you start asking detailed questions. If they don’t work with you to understand every single area where you’ll be using energy then they aren’t the right people for the job. Same thing applies if they want to sell you a solution that is not customised. You need a solar expert who is willing to work with the other people on the team to understand how the total solution will fit together.

4. A water recycling specialist with engineering skills. The water solution will always be the most difficult part of the project. Find an expert who is tenacious and can show you examples.

5. An energy expert to help you model the thermal performance of your design.

Step 4: Obtain the necessary information before moving forward

Get the necessary information from your specialist consultants before seeing your architect or planner

1. The water solution will be your most difficult solution. To help decide which way to go, ask your water expert to show you worked examples to understand:

a) What size roof you need

b) The size of the tank

c) The relationship between proportion of water recycled and tank size

d) Explain all elements of the recycling system itself (reed beds, UV treatment, pumps, tanks, maintenance access, overflow)

e) How they will deal with salinity

f) Are you going to keep all water on site or will you still use the storm water drains?

g) How much electricity will the system use?

h) Explain the space requirements

i) Help you to understand whether you need to reduce your water consumption

j) Provide calculations which include rainfall for drought! Rainfall will be in decline due to increased drought frequency. Are you ok with running out of water? What will you do if you do run out of water?

2. When determining your solar system get your off-grid solar specialist to:

a) Confirm roof size required

b) Forecast energy use (goal should be to provide enough energy for the household AFTER all the energy saving measures have been taken)

c) Explain implications of battery vs no battery (including space issues, whether it’s better for the environment, salvage value, importance of the right battery, solar analytics to make sure you use energy at the optimal time)

d) Explain things like local support for your solar if something goes wrong, quality of panels (cheap don’t last and create recycling problems)

3. Materials to be used in the renovation:

a) Your architect, designer and water recycling specialists will need to know what kind of products you want to use.

b) I have specified that I want to salvage as much of the existing property as possible. We are yet to understand how we will do that (i.e. storage of the salvaged materials, how will they be repurposed in a cost-effective way, how will we use old bricks, old bookshelves, cabinetry etc.). Note that it’s often more expensive to use recycled materials so I’m working with my designer and architect to understand how we might be able to keep costs down. There has to be a way! I just haven’t figured that part out yet, so if you have any suggestions, please let me know!!

c) I have specified that I will not be using concrete in the build as “Cement is responsible for concrete’s large carbon footprint; a ton of cement represents about a ton of greenhouse gas emissions”.

d) For the water recycling system, I have specified that there will be no chlorine or other chemicals used to treat the water for recycling.

e) If we can’t use recycled products, then they need to be sustainable. And for things that can’t be recycled (like paint) then we need to use non-toxic paints.

Step 5: Define your budget and your costs

1) Once you know what you want you can start costing it. If it’s too high then you can start figuring out which things are a lesser priority.

2) Make a list of all the things you’ll have to pay for (planner, architect, council fees, elements for going off grid etc.). Use my project as an example – I’ll be providing costing resources as I go, to help guide budget development.

3) Include a recommendation that all participants in the project provide a scope, timeline and budget so if they deviate from the budget you have recourse.

4) Also recommend that each participant in the project is aware of the total budget and the breakdown.

5) Make sure each invoice is itemised. Make sure you get a quote up front and that you have a way to prevent costs from blowing out. That can either mean asking for a retainer, or for the service provider to keep you posted on how costs are accruing.

Step 6: Sustainable design development

Work with your planner and architect to develop the design of the building so it’s within all relevant controls. This is where the architect and the planner need to work together to fit all the off-grid and solar passive stuff into your space (in my case a very small space!) while also keeping the council happy. Having the planner and architect work together means that you are more likely to have your plans approved as the planner will understand the Council’s decision-making process and will be able to guide your architect.

Step 7: Lodgement and Assessment

Make sure you submit a “pre Development Application”. Going straight to a DA might mean you get knocked back and that costs money! At the pre DA they will assess the project and more than likely require you to come back and make changes. Once you get the thumbs up from the pre DA, you can lodge the DA proposal with Council;. I am very lucky that I live in the Inner West Council area and my council is committed to reducing carbon emissions to zero. In which case, the council has been very supportive of my sustainability goals. We have recently submitted the second pre DA and are very hopeful that we get mostly ticks and not too many crosses so we can move to the next stage. Stay tuned… more to come!

Step 8: Approval and construction

Council approval and then going through the construction certificate stage and then actual construction. I don’t have much to say about this step yet as I’m still at the pre DA stage!


Did you find my step-by-step sustainable home design building guide useful? Do you have any suggestions for me?

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