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Avoid costly mistakes when buying container home or modular granny flats

Do you need a building approval for a pre built granny flat, modular or transportable home? What is the difference between building a kit home and a standard build?  Find out what you need to know to ensure you can legally use the product you buy in the way that you want.

Kit and modular homes can be a suitable option when building. They can sometimes save time and money but, and this is important to understand from the outset, these homes must meet the same construction standards as any dwelling. It pays to do your research before you buy to ensure you don’t have to make expensive upgrades the product you are looking to buy.

Here is a step-by-step guide to building these types of homes:

  1. Building Approval and Building Permits: It is very important to engage a Building Certifier before starting construction to ensure you will be able to obtain the necessary building permits. The Building Certifier will review the plans for the kit/modular home and advise of any non-compliance issues. They will also determine any planning requirements for your local area.  You will obtain a building permit once planning and any non-compliance issues are addressed.
  2. Building Plans: Many companies supply both construction and site plans for the product they sell. If they do not you will need to work with an architect, engineer or building designer to produce these.
  3. Engineering: Again, many companies supply engineered drawings for their product, but you need to ensure it meets the construction standards of the area you are building in. For example in North Queensland, it must be cyclone resistant and wind rated.  Additionally, check that the engineering covers the slab and footings for the structure. If not included you will need to engage an engineer.
  4. Plumbing and Electrical: If plumbing and electrical systems are not part of the build kit, you will need a QBCC licensed contractor to install them and they must supply the relevant Form 43s for the building permit.
  5. Energy Efficiency: You need to check that the home you are buying meets current energy efficiency standards, as the buildings orientation can impact the rating.
  6. Fire Safety: Your kit or modular home will require smoke alarms according to the Building Code Australia (BCA). In relevant zones it will require bushfire rating.
  7. Livable Housing: The kit/modular home must comply with the Livable Housing Provision and BCA.
  8. Building: Make sure the builder is QBCC licensed or complete an owner builders’ course to be able to manage the work yourself.

The best 7 questions you can ask the supplier.

If you are looking to purchase a kit or modular home, you may find the following questions helpful:

  1. Has the company obtained building approval for other homes in the area? Were any modifications required? Can they supply evidence of this or give references?
  2. Has the kit/modular home been designed to meet all the requirements of a dwelling in the Building Code Australia (BCA)?
  3. Is the home engineered to comply with the Building Code Australia (BCA) for the region you intend to build and will it be supplied with the relevant certificates and certified plans?
  4. Will any additional features or modifications be required to meet cyclone standards (if building in a cyclonic area)? Will any further engineering be required?
  5. Do any special provisions need to be made to meet bushfire standards?
  6. Does the kit/modular home come with any warranty that it will achieve a building approval?
  7. Are there any special requirements for site preparation and the construction of foundations?
  8. Is termite management included?

Is it cheaper to build with a kit?

This really depends on the inclusions and whether it is designed to the standards set out for a dwelling in the Building Code Australia (BCA). Ensure the kit/modular home, you are buying, is engineered and come with all the relevant paperwork. If not, retrofitting the kit to meet the relevant standards can be expensive. It pays to do the homework up front.

Can I get building approval on a kit or modular home?

As with everything in building approval, it depends on the individual circumstances of your situation. However, using this guide, and getting the right answers, should make the process much simpler. You will still need planning approval to situate the dwelling on your block.

A common checklist for a granny flat / container homes (note further items may be required for Building Certification).

  • A Form 15 from an RPEQ Structural Engineer to verify that the structure is suitable for Class 1a use (this should come with the product you buy).
  • Footing and Slab designed for Class 1a (vapour barrier to Australian Standards). This may be with the product you buy or you may be required to engage your own engineer for this.
  • Energy Efficiency schedule minimum 7 star. This may come with the product you buy but you will need to make sure it can meet the standard.
  • Soil Classification. You will need a soil test if you don’t have one already.
  • Termite Barrier.
  • Minimum ceiling height – 2400mm for habitable areas. Many modular products do not have the correct ceiling heights.
  • Minimum flood height (1% ADP + 300mm if in flood overlay).
  • Rooms must have natural light and ventilation in accordance with Building Code Australia (BCA)
  • Smoke alarms in accordance with Australian Standard
  • Waterproofing in accordance with Australian Standard
  • All facilities required in accordance with with Building Code Australia (BCA)

We hope that this helps you begin to plan your kit/modular home. We would be happy to quote on the building approval or provide further advice just email your plans.

Top Tip: Many products are sold as transportable homes as something temporary and transportable does not require a building approval. Please check with your local authority as to how long a transportable home can remain on your property as many limit the time they can be there without being moved. The local authority will not provide plumbing and waste to a transportable home.

Remember the advice given in this article is of a general nature and may vary upon individual construction circumstances. Always obtain your own advice to ensure it is specific to your individual construction needs.

John Munro Tiny Home
John Munro Builder Tiny Home