Do portable buildings need a Building Consent?

Table of Contents

Executive Summary
Case Study
The Determination Regarding “Vehicle”
The Determination Regarding “Immovable”
The Determination Regarding “Permanent Occupation”
Related Issues
      Does a Vehicle have to be Registered, Warranted, or Towable on the Road?
      Specific Mention of Caravans
      Is Moving a Home onto Site Considered Building?
      Are two Vehicles Locked Together a Building?
      Does Building a Deck Require Building Consent?


With public pressure and even government attention turning to affordable and diverse housing options, it is becoming increasingly important for everyone involved to be clear about what is and is not possible within the law. One issue that keeps coming up, and is often misunderstood by local councils, is when a portable building is considered to be a building or a vehicle, with regards to requiring a Building Consent.

To be clear, Cosy Homes understands that Building Consents can serve a valuable purpose, and that quality homes are important – this is why Cosy Homes are built to Building Code by licensed builders. However, we are also aware that there are many cases where the act of getting a Building Consent is an unnecessary and undue burden (e.g. the owner does not plan to keep the unit in that location for very long, or the requirements for earthquake safe foundations are irrelevant because the vehicle on wheels is already earthquake safe). Therefore, we think it is important that people have the option to not get a Building Consent, and we believe the central government has made this possible in their nationwide legislation (within appropriate guidelines), therefore it is local councils that often need help to interpret this carefully designed legislation and support the rights of their citizens.

Executive Summary

Broadly speaking, the Department of Building and Housing is consistently clear that a home does not need a Building Consent if:

1. It is a vehicle (i.e. has wheels, a towbar, and is movable), and one of the following is true:

a. The vehicle is not fixed to the ground in any way that needs a professional tradesperson to detach it, OR

b. The vehicle is not permanently occupied.

It also clarifies a few related points:

  • A vehicle does not have to be registered, warranted, or towable on the road.
  • Caravans and mobile homes are specifically mentioned as examples of vehicles.
  • Moving a vehicle onto a site does not need a Building Consent.
  • Locking two vehicles together typically makes them immovable, so would require them to get a Building Consent. However solutions to this are discussed.
  • Building a deck does not require a Building Consent.

At Cosy Homes, we have gone above and beyond to ensure we understand the law and comply with it. In particular, we are careful to comply with points 1 and 1a above.

Case Study


The most definitive definition and ruling on this question comes from the central government – The Department of Building and Housing (DBH). DBH administer the Building Act and the Building Code, and have ultimate responsibility in deciding how the Act is interpreted. Local councils who are unsure of interpretations can submit their case to the DBH, who will make a determination. Local councils are then legally obligated to follow the DBH determination.

To save a lot of individual hassles of local councils making incorrect interpretations and wasting the time of the council, the client and the DBH in asking for individual determinations, I thought it was prudent to do a literature review of past determinations that most closely relate to this question. While I have not looked at all DBH determinations, I have studied most of the 30 or so determinations in this area.


The following is perhaps the best example:

Determination 2015/044: Regarding the issue of a notice to fix for a prefabricated unit and whether the unit is a building or a vehicle.

Date issued: 8 July 2015.


A property owner contracted a manufacturer of small homes on wheels to build one on his site in Balfour. When it was partially finished, Southland District Council issued a “notice to fix” on the grounds that it was a building and therefore this was building work and a building consent should be obtained for it. The DBH determined that the home was in fact a vehicle, and overruled the Southland District Council. The council disagreed with the draft determination and gave their reasons, however the DBH gave clear logical responses and maintained their determination.


Section 2 details how the home in question was very similar to a Cosy Home in the following ways:

  • It was quite large compared to a traditional caravan or tiny home at 40sqm (Cosy Homes are typically 38 or 50 sqm).
  • It’s subfloor was built on a metal sub-frame with axles, inflatable tyres and a tow bar. Its sub-floor was timber joists, with sheet flooring installed over this. Cosy Homes also have metal sub-frame with axles, inflatable tyres and a tow bar. Cosy Homes’ sub-floor is of higher quality (steel joists with a thick insulated panel over this and then sheet flooring), but this does not materially affect the determination in any way.
  • It used aluminium window joinery and corrugated iron external wall cladding and roof. Cosy Homes typically uses uPVC window joinery and colorsteel roof – again higher quality, but functionally identical for this determination.
  • The unit was to be partitioned to provide separate sleeping, bathroom, and living areas. The latter to include kitchen facilities. Power was provided via a standard caravan lead, and water supplied from a hose to an external tap. LPG was used to heat water and for cooking. This is all functionally identical to Cosy Homes.
  • It used “levelling stays” to take the load off the tyres and provide more stability. Cosy Homes use “feet” that serve the same purpose.
  • The manufacturer refers to it as a caravan. And states their “caravans are designed to be towed with a tractor”. Cosy Homes are also designed to be towed with a tractor and we have pictures of us doing so if required.
  • As an aside, the manufacturer routinely constructs these units for holiday parks (section 4.3).

The Determination Regarding “Vehicle”

Section 5 has a detailed discussion on this, but it is well summarised in 5.1.8:

(italicised texts are direct quotes from the Determination)

5.1.8 To summarise the position as to when vehicles will be treated as buildings:
  – if something is a vehicle, and it is immovable and occupied by people on a permanent or long-term basis, it will be treated as a building
  – if something is not a vehicle, the question of whether it is to be treated as a building will fall to be considered under the main definition of building in section 8(I)(a) of the Act
  – if a person claims something is not subject to the Building Act because it is a vehicle, they must establish the thing is a vehicle or motor vehicle, and that it is movable or that it is not occupied by people on a permanent or long-‘term basis.

This is also summarised well in Appendix A, which contains a clearly defined decision tree.

The first check determines if it is a vehicle.

5.1.5: …”vehicle” is not defined in the Act, so the natural and ordinary meaning applies (Oxford Dictionary of Eng|jsh): “a thing used for transporting people or goods, especially on land, such as a car, lorry, or cart. …

5.1.6 The reference to vehicle in section 8(I)(b)(iii) also includes a “vehicle or motor vehicle” as defined in section 2(1) of the Land Transport Act 1998.  The relevant part of that definition provides:
    a) means a contrivance equipped with wheels, tracks, or revolving runners on which it moves or is moved;

5.2.2: The unit, although only partially constructed, has wheels and axles, and in my opinion is clearly designed to be capable of being towed.

5.2.3: I also accept the manufacturer’s submission about the circumstances in which the unit can be towed, and that the unit’s construction is sufficiently robust to enable this to happen.

5.2.4: As a result, I consider that the unit is a vehicle, both within the natural meaning of that term, and as defined by the Land Transport Act 1998.

5.1.7: If a particular structure is a vehicle, it will then only be treated as a building for the purposes of the Act if it also satisfies the two further requirements in section 8(1)(b)(iii) of the Act.  These are that the vehicle must be ‘immovable’ and ‘occupied by people on a permanent or long-term basis’

The Determination Regarding “Immovable”

Therefore, the next relevant test becomes is it “Immovable”.

5.3.3: Whether a vehicle is immovable is a question of degree that will turn on a range of factors such as:
  – Whether the vehicle is attached to the ground and how easily those attachments can be removed;
  – Whether the vehicle has been connected to services and how easily those can be removed;
  – Whether the vehicle has retained its wheels and the ability to be towed or to move itself;
  – Whether structures have been attached to the vehicle, such as decks, verandahs, or additional rooms, and how easily these can be detached.

This is why, at Cosy Homes, we have made the following careful design decisions:

  • We developed our patent pending feet (only about 40kg each), to ensure they cradle the home and do not attach it to the ground – the home can be lifted off the feet with no detaching required whatsoever, or the feet can also be removed while the home is still in place.
  • We ensure all services are easily detached, e.g. gas, power and water are easily unplugged, waste water is connected with a flexible, quick-release coupling (more details available on request).
  • Our wheels and towbar are retained by each customer. While the towbar can be telescoped into the sub-frame to keep it out of the way, it is very easy to extend again.
  • We ensure that any possible decks or verandahs are preferably completely free standing, but at the least, are very easy to detach.

Therefore, none of our Cosy Homes are immovable when delivered to the client. What happens after that is up to the client, but we ensure each client is aware of the regulations and implications.
In this determination, the home is not considered to be immovable:

5.3.4: As stated in paragraph 5.2.2, the unit is clearly designed to be capable of being towed…

The levelling stays used to keep it stable and take load off the wheels (in 2.6) are not considered to change this determination, as they are easy to remove (4.3).
In this case, sewage had not yet been connected, so we have to refer to other determinations for this guidance.

In a different Determination (2014/025), section 4.3.3 found the home to be immovable because:

…the unit also has permanent services connections that would require the services of a person authorised under Plumbers, Gasfitters, and Drainlayers Act 2006 to disconnect.

This makes it clear that the logical test used by the DBH is that it is immovable if the services can only be removed by a person authorised under Plumbers, Gasfitters, and Drainlayers Act. Therefore, more broadly, a home is considered movable as long as none of the connections need to be removed by a qualified tradesman.

This is why Cosy Homes only need one thread loosened in order to remove plumbing fittings and why Cosy Homes use a Caravan Style plug, which can be disconnected by any fit adult.

The Determination Regarding “Permanent Occupation”

If the home is considered to be a vehicle, then it can only be considered to be a building if it is both immovable, and “occupied by people on a permanent or long-term basis”.

In this determination (Determination 2015/044), permanent occupation is not discussed in detail, because it is irrelevant, as it was already determined to not be immovable, therefore not a building.

However, we can confirm this decision path in a different Determination (2014/025) where the vehicle was immovable, but used temporarily. Section 4.4.1:

The unit is designed and fitted out for habitation. The owner has stated his intention to construct a dwelling on the site at a later date and that the unit is meant to be temporary and would be occupied for ‘occasional/holiday/weekend use’. Given that it is not intended to be occupied by people on a permanent and long term basis I am of the view that it doesn’t met the test under section 8(1)(b)(iii) of the Act.

Which therefore reaches the conclusion that it is not a building in section 4.5.1:

In conclusion, although the unit can be moved it has permanent services connections that are not easily disconnected.  However the intended occupancy is not on a permanent or long term basis but for occasional use only.  Taking into account the features of this particular unit in these circumstances, I consider that the unit is not a building under section 8(1)(b)(iii) of the Act.

Related Issues

Does a Vehicle have to be Registered, Warranted, or Towable on the Road?

In a different Determination (2014/025), in section 3.1 the local council felt that the home had to be a registered and warranted vehicle that could be towed on the road:

In the application for determination the authority submitted that it had applied the test ‘is it permanently occupied’, and ‘is it a vehicle or can it be towed if it had a warrant [of fitness] and a [vehicle registration]’.  The authority accepted that it was not permanently occupied, but believed that as the unit was 3.1m wide it could not be towed but needed to be transported as a load.

The DBH overruled the local council’s interpretation in section 4.2.10:

In my view, whether the unit can be considered a vehicle, does not turn on whether it is registered and has a current warrant of fitness. I consider that the unit is a vehicle, both within the natural meaning of that term, and as defined by the Land Transport Act 1998.

And then clarifies in Section 4.3.1:

The fact that a vehicle cannot be legally towed on a public road is not the same as being ‘immovable’ for the purposes of the Act.

It is therefore very clear that a vehicle does not have to be registered, warranted, or towable on the road.

(It is worth noting in the same Determination (Section 2.7), a response from NZTA states that:

any over-dimensioned vehicle … could be registered as a trailer but should not be able to obtain a warrant of fitness.)

Specific Mention of Caravans

In a different Determination (2016/019), caravans are discussed:

4.3.5: Caravans or mobile homes are clearly vehicles; while they perform a similar function as a dwelling, in that they are used for sleeping accommodation and may contain sanitary facilities

…A vehicle such as a caravan or mobile home only falls within the Building Act if it meets the test under section 8(I)(b)(iii), being that it was both immovable and occupied on a permanent or long-term basis.

So the DBH is very firm in their view “Caravans or mobile homes are clearly vehicles”. Cosy Homes are designed to be caravans or mobile homes, and are indisputably regarded as vehicles when delivered to a client. What happens after that (regarding “immovable” or “permanently occupied”) is up to the client, but we ensure each client is aware of the regulations and implications.

Is Moving a Home onto Site Considered Building?

In a different Determination (2017/065), this is discussed in detail:

4.5: In previous determinations I have considered the relocation of buildings and whether this constitutes “building work” under section 7 of the Act (see for example 2011/104 and 2014/0304).  I maintain the view set out in those determinations, that the act of moving or relocating a building and placing it on site is not “building work”.

4.7: “Building work” is defined in section 7 of the Act as:
  (a) means work—
  (i) for, or in connection with, the construction, alteration, demolition, or removal of a building; and
  (ii) on an allotment that is likely to affect the extent to which an existing building on that allotment complies with the building code; and
  (b) includes sitework; …

So while “Building work” includes “removal of a building”, it does not include moving a home onto a site.

It is therefore very clear that moving a home onto a site does not require a Building Consent. The DBH has consistently made this determination at least 3 times (2011/104, 2014/0304, 2017/065).

Are two Vehicles Locked Together a Building?

The matter of connected prefabricated units was considered in High Court in Te Puru Holiday Park Ltd v Thames Coromandel District Council (HC Hamilton CRI-2008-419-25, 11 May 2009, Duffy J):

[21]The unit on this site is described as a duplex; it comprises two [proprietary] units locked together to form a single dwelling.

And the result is (paraphrased):

when locked together, creates a new structure, which has no evidence to suggest that it could move or be moved on the road.

This view as upheld by the Court of Appeal in Thames-Coromandel District Council v Te Puru Holiday Park Ltd ([2010] NZCA 663).

So the connected structure was evaluated as a single whole structure, which was considered to be a building. As it is unlikely that two vehicles could ever be joined to create a single structure that is still a vehicle or movable, Cosy Homes would suggest that this should only be attempted if a Building Consent is obtained, which is a viable option as Cosy Homes are built to Building Code by licenced builders.

You can still enjoy the benefits of two or more vehicles without a Building Consent – just be careful no to physically connect them. We have seen fantastic examples of homes on wheels (aka vehicles), on either side of, or surrounding a shared deck and veranda (which should not require a Building Consent). This can create a beautiful, sheltered, outdoor living space. Just be sure to not fix your vehicles to the veranda or deck, and it is highly recommended that the vehicles are situated so that they are able to be towed away from the shared space if required.

Does building a Deck Require Building Consent?

In a different Determination (2017/065), it states:

4.8: The construction of the deck would not require building consent because it is exempt as provided for in Schedule 1 of the Act.

It is therefore very clear that building a deck does not require a Building Consent by itself.
However, care still needs to be taken:

  • Not to attach a fixed deck to a movable vehicle. At least, not to attach it in a way that requires a qualified professional to detach it.
  • Not to design the deck in such a way that it makes the vehicle unable to be moved.


Numerous determinations, including Determination 2015/044 include a flowchart to clearly describe the decision tree that can be used. This is included below: