Shipping Container Granny Flats – The Definitive Guide
If you have been looking for a cheap alternative, you may wonder; can you build a granny flat from a shipping container?
Yes – a shipping container can be approved as a granny flat. To be legally approved, it must be changed from a movable dwelling into a permanent, “habitable”, building. This involves making modifications such as adding doors, windows, appliances, plumbing, insulation, etc.
Today I will discuss how to legally build a shipping container granny flat. I will cover the nasty traps to avoid when building with shipping containers. Provide information on the best designs for shipping container cabins, plus a whole lot more.
With all of this content to cover, lets begin.
How to Build a Shipping Container Granny Flat
There can sometimes be more steps involved in building a shipping container granny flat than a traditional granny flat.
Do Your Research – This is always the first and most important step – contact your local Council and find out your regulations.
Preliminary research will save you a ton of headache before building
If you live in NSW like I do, another hint is to enter the address of your property into the NSW Planning Portal. Here, you will find any planning constraints and zoning rules that you are affected by. It’s important to know whether your Council will approve a shipping container granny flat, as to not make plans just to be let down.
Start researching shipping containers – you must have a rough idea of what you want. There are many different types and sizes of shipping containers, and this article provides great advice as to what makes a good granny flat. Also, know whether it is possible to get a container onto your land. A local crane company will generally give you a free quote to check access to your site.
Start Your Approval Process – Now you are armed full of knowledge, you can begin your paperwork.
For a shipping container granny flat, you only have one option for approval – usually a Development Approval. Contact your local Council for their regulations, the application forms, and all necessary paperwork that must be submitted with your application. You can do this in person or download them from their website.
Have Your Plans Checked by a Certifier – Once your paperwork is ready, it’s time for someone to come give them the stamp of approval. You can choose from a private certifier or the local Council.
Purchase Your Shipping Container – If you receive approval, you can now purchase your shipping container. It is important to have the knowledge before you purchase anything, so you don’t end up with an empty container sitting on your property.
Start Building – You were granted your Construction Certificate when the certifier came over to check your plans. Now you can start building, making the modifications required so it is classified as “habitable”. It makes sense – you really do need doors, windows, fixtures, appliances, and plumbing in your granny flat.
Get the Final Tick of Approval – Once your “building” is finished, the certifier will visit again, to check you followed the plans submitted. If they’re happy you completed the building legally, and it’s safe to live in, you will be given an Occupation Certificate. Your shipping container granny flat is now successfully approved!
Can You Legally Build a Container Home Granny Flat?
It is important to note that every local Council has their own rules regarding living in a shipping container. Most are similar – they will treat a permanent shipping container just as they would your backyard shed.
Though what’s important about shipping containers is that they are movable dwellings so are not classified as “buildings”, meaning:
Granny Flat Shipping Containers – Nasty Traps to Avoid
Although shipping containers are ideal for building a granny flat, as with any building method they have their pitfalls.
So, it’s important you do your research first, to avoid these issues.
Here are common problems to look out for when building a shipping container granny flat.
Do You Have Transit Insurance? – If anything goes wrong you will be left to pay for the damage. Insurance is essential in transport!
Do They Comply with Your Local Councils’ Regulations? – As a granny flat, a shipping container will require approval from your local Council. In some areas they may not be allowed if they look ‘out of character‘. It’s important to contact your local Council and get all information on the approval process before purchasing your shipping container.
NOTE: All it takes is a few phone calls – don’t miss this vital step. If you do, you may find yourself buying something you’re not allowed to use.
Have You Chosen the Correct Container? – Especially important is the type and size of container. Some are perfect for granny flats, some probably won’t be approved. For example, a high cube container may be too tall for your local council.
Best Designs for Shipping Container Cabins
With shipping containers, your options for design are endless, as you can combine them together until you reach your maximum floor space. They can also work on any complex site.
This elaborate home in Denmark could serve as inspiration.
Appliances (i.e. a hot-water system, oven, washing machine, etc).
Plumbing, draining and sewerage.
This is required as part of Council approval, to turn what was a transportable dwelling, into a permanent building.
However, with every modification, you do risk making the shipping container weaker. Though shipping containers are designed to be strong, they aren’t designed to be cut and re-joined several times. So, only cut them when you need to. While they are flexible in their design, they will need to be sufficiently reinforced to ensure they remain structurally sound.
Welding and cuts should be done by a professional
All welding must be performed by a professional, and all cut outs must be approved by a structural engineer. This ensures your shipping container granny flat remains safe.
Shipping Container Granny Flat Costs
A lot of people opt for a shipping container granny flat, as they can be cost effective.
While the containers themselves cost roughly $5000 (depending on their size), don’t forget about the additional costs.
Expect to spend a quite a lot of time and money before your shipping container qualifies as “habitable”.
How Do You Relocate a Shipping Container Granny Flat?
A shipping container requires preparation for transportation. Ensure you have received building approval from your local Council, then begin planning its’ journey to your property.
Plotting the route your shipping container will take.
Ensure streets you are travelling are safe for an oversized vehicle – Consider trees, low powerlines, bridges, or busy/hazardous roads (traffic control may need to be organised).
Once your route is approved by Council, present it to your transport company.
Ensure you do this before you intend moving your shipping container – if you don’t, you may be charged extra fees.
Make sure your land is ready for the company when they come – your foundation and connections are completed – so your shipping container can be installed as soon as it arrives.
You will also require a crane at your site, to remove the shipping container from the transport vehicle.
This can cost over $1000 – i.e. $400+ an hour for a large crane (which will be needed if your site is not easily accessible).
As this is quite expensive, get at least 3 quotes from local crane operators.
What Foundation is Required to Build a Container Home Granny Flat?
Unlike a traditional granny flat, less construction work maybe required when building a shipping container granny flat.
This helps to save on costs.
Though a level-base is still required for your shipping container to sit upon, depending on your soil type, you may be able to achieve this using low-cost decking.
Another benefit of this is that the granny flat is also easy to move in the future, if you want to move home and take your granny flat with you.
The 2 foundation choices for building in Australia.
Cheaper than a concrete slab, and still keeps the container elevated, avoiding the rain and any potential issues with flooding.
Can You Use Second-Hand Shipping Containers?
I DO NOT recommend purchasing a used shipping container.
Who knows what you get on the second hand market
Used shipping containers do not come with a long, detailed history. This causes many problems. Plus many councils will flat out refuse to allow a secondary dwelling to be built with a used granny flat.
They may not be as structurally strong.
You do not know whether they have been dented, hit, or dropped from a large height, all of which can weaken them.
They are potentially hazardous.
You are also not aware if they are lethal – what deadly poisons may have once been inside (i.e. radioactive materials), which have left dangerous toxins behind.
Meaning, there is a chance you are risking your health and safety by housing yourself in a shipping container with a murky history.
They have close contact with the container, so will keep water away from the metal, prolonging its life.
Wool – Like blanket insulation but using sheep’s wool.
Cotton – Also like blanket insulation but using recycled cotton.
What method should you choose?
It isn’t about one type of insulation being better than another.
Basically, it depends upon your climate, skill-set, and budget.
You don’t need to limit yourself to one type of insulation – multiple insulation methods can be combined. For example:
You could use a traditional insulation method, and cover the area with spray foam, creating a waterproof seal, or
One type of insulation can be used on your walls and roof, and another underneath.
Just choose methods that meet your needs and withstand your climate. More consideration should be given to areas in more extreme climates, such as Tasmania and the Northern Territory.
Below is a video explaining the traditional method of insulation – as stud walls (frame) is first required, you must insulate any gaps between studs as well.
Can You Build a Two-Storey Shipping Container Granny Flat?
Yes – as long as you follow Councils’ regulations, design to your hearts’ content!
Due to their shape and material, shipping containers can be easily modified. So, use multiple shipping containers and join them together, making a 2-storey granny flat.
The use of shipping containers as granny flats has grown in popularity over recent years, as they are a strong, affordable option. Most Councils will consider a shipping container a shed, so they require Development Approval.
However, NSW has made it easier for containers to be converted to granny flats, with the Section 68 Application. As for other states in Australia, just make a call to your local Council for information on your regulations.
Unlike traditional granny flats, little construction is required, helping to keep costs low. They are flexible in design and a modified shipping container can give an overall aesthetic appeal to any property.
Finally, a shipping container is going to require modifications, to classify as a “habitable” building.
To change something that once was a movable dwelling into a permanent building, you must add:
So, it may also need reinforcement for restrengthening. They will also require insulation. Many types of insulation can effectively be used for your container, including:
Spray foam insulation.
I recommend buying a new shipping container – unlike a used shipping container, they have no:
Dark, murky history, or
Damage from being loaded and unloaded, bumped around, etc.
Expect to pay at least $5000+ for a new shipping container, but you have more chance of gaining approval for your granny flat.