How Big Can You Build a Tiny House on Wheels?

A Guide To Size and Weight Limitations

Tiny homes have existed in some form for a very long time. Back when all dwellings were small, most people simply called them houses. However, as houses became bigger, so did our understanding of what a home was.

If you are thinking of transitioning to tiny living, look in your local area or where you hope to live. Find out if there is already a group. This can be a great resource to learn what is allowed and what is being pushed for locally. Next, contact your local council for the necessary guidance, permits, and other requirements for a tiny house on the road. While rules vary from council to council and state to state, there are standard dimensions that you need to know for building a tiny house on wheels.

Should you build your tiny house on wheels or on land?

Tiny houses can be anything from a specially built house on wheels to a compact, permanent structure on land. But the idea of living in a tiny mobile home is what many people find attractive. The two most favorable reasons are mobility and getting around local rules on the minimum structure size.

For one, it takes more time and money to build a tiny house on foundations on a block of land and requires regular council approval and applications. In addition, tiny houses on wheels are not permanent structures. Therefore, building codes and permits don’t apply. It doesn’t mean you shouldn’t double-check with your local council before going ahead and building one, though.

For another, the best advantage of owning a tiny house on wheels is the adventure of living off the grid. It is like simply renting a spot of land from a farmer somewhere. If you’re itching for a change in environment, you could move your home elsewhere.

It is best to read up on local rules as very few local governments in Australia consider tiny houses on wheels legal. Instead, they tend to look at tiny houses as a variation of a caravan – for which they have different laws.

As a general rule, a caravan does not require approval from councils. But they can limit the time you have to live in one. For example, NSW legislation may permit you to park up to two caravans, campervans, or tents. Yet this is on a particular site and for only 48 hours at a time. Local laws may require you to obtain a permit for occupation for a limited period. It is where the applicant may apply for an extension, allowing living in a caravan where there is no commercial interest. Restriction for this is an occupation to only 30 or 60 days.

You can become a part of the tiny house movement in many ways, depending on what might suit your situation. Researching the area is vital for this one.

What are the ideal dimensions for your tiny house?

Length

Tiny houses should be 12.5 meters long, according to the Vehicle Standards Bulletin 1. It notes that, besides a semi-trailer, the trailer length must not exceed 12.5 meters. For a semi-trailer, the Point Of Articulation (POA) to the line from which the rear overhang is measured must be a maximum of 9.5 meters. Also, the forward projection from the POA must be within a radius of 1.9 meters. Then the distance from the POA to the rear end must not exceed 12.3 meters.

Width

Based on the Australian Design Rules, the maximum width for a tiny house is 2.5 meters. Is it possible to make your tiny house as much as 3 meters wide? Yes, you can, BUT there are heavy consequences with that decision –

  1. Making your tiny house 3 meters wide will mean that your tiny house vehicle cannot be registered as a caravan. It is because the official vehicle limit is 2.5 meters wide.
  2. Depending on local council rules, your 3-meter wide tiny home could be considered an ‘unauthorized building.’
  3. Your tiny house may be considered delinquent on filing the necessary planning permits and Development Application (DA)
  4. The bigger you go, the bigger and heavier the trailer will be, and the less weight you’ve got in the plans left to build a house under 4.5 tonnes. This will be explained further in the weight limitations.

Your best defense is to show that your tiny house is not a building requiring approvals but rather a “caravan.” For example, you can have the registration papers say that your tiny house vehicle is a registered caravan. To add, it has to comply with road vehicle specifications according to the state and national road authorities. In that case, you’re in a pretty strong position to avoid further confusion about your tiny house in the eyes of the council.

Height

The maximum height limit for any road vehicle in Australia to be legal is 4.3 meters. This limit is except for livestock trailers.

What are the possible consequences of going over the height limit? For tiny houses over 4.3 meters, you will want to pay particular consideration to bridge clearance heights. You’ll later find it a problem when transporting your precious tiny house if you don’t. Also, if your tiny house is over 4.3 meters and still roadworthy, you may be able to transport it as a Class O. Check with your local council for the required vehicle permits as this can be considered an oversized light vehicle. You may be able to travel this over-height tiny house on Australian roads. But it still cannot be registered as a caravan in Australia. So all the legal consequences mentioned earlier should apply.

What is the ideal weight for your tiny house?

Weight

Weight restrictions are the number one thing you must keep in mind before planning your tiny home. If someone says the trailer is rated to 3500kg, that does not mean you can go ahead and build a 3500kg structure on that trailer. You first have to subtract the weight of the trailer itself. So when doing your weight estimate, there are 3 parts to keep track of:

  1. The ‘tare weight’ or the weight of the trailer when empty;
  2. The “house” part you build on the trailer;
  3. All your belongings inside the tiny house vehicle when moving down the road.

This “all-up weight’ must be less than the weight rating of your trailer. This way, it can be safely and legally towed on the roadway.

How much weight can a trailer truck handle? Tiny house trailers are often rated to meet standard weight ratings. You can find these ratings on the compliance plate of your trailer. It will have the number of kilograms specified as the ATM or Aggregate Trailer Mass. Trailer manufacturers identify it as the trailer’s maximum capacity. The most common weight ratings are 3500kgs, 4500kgs, or more than 4500kgs.

What if your tiny house exceeds the maximum ATM? Your tiny house is not roadworthy if its overall weight is above the specified Aggregate Trailer Mass (ATM). These are a few reasons why this will be a problem.

  1. You cannot tow your tiny house on the road using its wheels under any circumstances. This even with an ‘Unregistered Vehicle Permit’ (UVP), because UVPs are only for roadworthy vehicles.
  2. Only one way to transport your overweight tiny house on wheels is loading the tiny house onto the back of a low-rider trailer or a truck using the truck’s tray. (See image below)
  3. The trailer’s brakes can’t adequately stop your tiny house vehicle when being transported. You could potentially push the towing vehicle out into traffic.

The 6-metre Kirra portable farmhouse on a flatbed truck.

Is Your Tiny House On Wheels Road-worthy?

Local transport authorities first inspect your caravan’s roadworthiness. It is part of registering before you can legally take your tiny house on the road.

If there is a need to tow an unregistered caravan, make sure first to get permission. If applicable, obtain an unregistered vehicle permit from your local highway authority.

Contact your local highway authority for any information regarding vehicle standards. Generally, once the requirements have been met and fees paid, they will provide you with number plates. You can then be on the road in no time. Also, have your caravan checked by a mechanic for good measure.

Getting your vehicle up to a standard of roadworthiness and obtaining a certificate for it is a way to register your caravan. Familiarize yourself with the process required by your state or territory’s highway or road authority:

NSW
NSW Transport

QLD
QLD Transport

VIC
VIC Roads

SA
SA Department For Infrastructure

TAS
TAS Transport

ACT
ACT Transport

WA
WA Main Roads

NT
NT Driving & Transport

We hope this guide is useful in answering some of the FAQs about how big you can build a tiny house on wheels. Explore our mods and get in touch to find out if the tiny house lifestyle is for you.

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