What is a shipping container?

Shipping container architecture is a form of architecture using steel intermodal containers (shipping containers) as a structural element. It is also referred to as cargotecture, a portmanteau of cargo with architecture, or "arkitainer".

The use of containers as a building material has grown in popularity over the past several years due to their inherent strength, wide availability, and relatively low expense. 

Shipping container granny flat in Victoria, Australia, 20ft, added staircses, propped-up weatherboard design.

A shipping container granny flat as well as a home, have dually been built with containers because they are seen as more eco-friendly than traditional building materials such as brick and cement.

Why is a shipping container appropriate as a granny flat?

Due to their shape and material, shipping containers can be easily modified to fit many purposes, specifically the purpose of building container granny flats. 

Container home in Tasmania, Australia, 40ft L-shaped design.

Reasons for this include; the accessibility of shipping containers — because of their wide-spread use, new and used shipping containers are available across the planet, transport – Because they already conform to standard shipping sizes, pre-fabricated modules can be easily transported by ship, truck, or rail and durability — They are designed to resist harsh environments, such as on ocean-going vessels or sprayed with road salt while transported on roads. Due to their high strength, shipping containers are usually the last to fall in extreme weather, such as tornadoes, hurricanes, and tsunamis.

Unlike traditional dwellings, very little construction is required when creating a granny flat from an existing shipping container, which helps to keep the costs down. 

The containers themselves cost around $4,000, and the rest of the construction can range from $30,000 - $100,000 depending on the size, materials and cost of labour.

Other factors also include the volume of the containers. Depending on their size ie 20ft or 40ft, their costs will effectively vary due to the inevitable extra materials, foundation costs, fabricating, etc that different sizes require.

DIY used-shipping container granny flat vs a ready-made granny flat

A DIY used-shipping-container-converted granny flat is overall more of a rewarding experience, to turn into a cabin, room, studio, and is more portable. And (depending on how thin your wallet is) it can be of a similar price to ‘flatpack granny flats’ coming in at around $30,000, similar to the baseline cost of shipping container granny flat. 

Shipping container granny flat, 20ft, floor-to-ceiling glass entry design.

It’s a bit like asking if you’d like a flatpack home or an architecturally-designed home, if they were around the same price…I know which one I’d be choosing.

Additionally, container granny flats can be ready made too, for sale on the world wide web, on places like eBay, for around the same price as building them DIY.

Hidden costs

While the hidden cost of a level base (foundation) is still required for your shipping container to rest upon, this can be achieved simply with a low-cost decking.

This also makes the granny flat easy to remove in the future if you choose to sell and your new residents don’t wish to keep your granny flat.

Yellow-solar-panel, 20ft container granny flat with astro turf in Brisbane, Australia.


In NSW, the conversions of containers to granny flats have been made easier to build, due to council’s approval process on all residential properties in just 10 days (permits).

As for the rest of the states in Australia, it will be a quick call to your local council, although some information states that for some, the approval process of a permit has been the most time-consuming part.

Companies do, however, supply ready-made grnny flats, cutting time out of the ‘DIY’ process if you do find yourself wanting a ‘quick-fix’. Companies include; Container Constructions, iBuild Building Solutions, Container Build Group, IQ Container Homes, you can even find pre-made shipping container granny flats on eBay.