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Living in a modular home

From Modular Living Australia — the independent knowledge base Last updated: 13 Oct 2026

Once installed, a modular home is regulated as an ordinary house: the same 2.4 m minimum ceiling height applies to its habitable rooms as to any other house.^[1] What shapes daily life differently is the module itself — room proportions set by road transport, joins running through larger rooms, and walls and floors doubled where modules meet. The National Construction Code sets no sound insulation level for walls inside a single house.^[3]

Most writing about modular homes is about buying one: price, approval, finance, delivery. This page is about the part after the keys — what a resident is likely to notice, which of those things are fixed by regulation, which depend on the design, and where reliable information runs out.

Room shapes and ceiling height §

The road decides the room. Modules have to travel as loads on public roads, so the width and height of each module is limited before design starts, and rooms in a modular plan tend to be long rectangles sized to the module width. Floor plans and customisation in modular homes explains where joins fall and why kitchens and bathrooms usually sit within one module.

Ceiling height is not lower by rule. The NCC sets a minimum of 2.4 m for habitable rooms other than kitchens, and that applies to a modular home exactly as it does to a site-built one.^[1] One builder describes an industry-standard module as 3.4 m high from floor to floor;^[2] that figure is commercial guidance and includes the module's own floor and ceiling structure, so it is not the height you will see inside. The internal ceiling height of a specific design, and whether it can be raised without exceeding the transport height on your route, is a question for the builder.

Sound inside the house §

Sound between rooms in a detached house is a design choice rather than a regulated standard. The NCC's sound insulation requirements for houses apply to separating walls between dwellings — for example in a duplex or townhouse — and to walls between a house and an unrelated garage or shed. They impose no requirement on walls within a single dwelling.^[3]

Modular construction does change the anatomy of walls and floors. Where two modules sit side by side, the junction is formed by two walls, one from each module; where modules are stacked, there are two floor or ceiling structures.^[4] Field measurements in multi-unit modular buildings in Canada found that those doubled walls can perform 5 to 10 rating points worse than expected because of the extra cavities, while floor assemblies generally met code targets.^[4] Those results come from apartments overseas, not Australian houses, and are included only to show that a doubled wall is not automatically quieter.

If quiet rooms matter, insulation in internal walls and the position of bedrooms relative to living areas and module junctions are the things to ask about.

Temperature and energy §

A modular home is assessed against the same energy efficiency requirements as any new house. The energy efficiency provisions of NCC 2022 commenced on 1 May 2023, with adoption dates varying by state and territory.^[5] Where each jurisdiction stands is covered in the 7-star NatHERS rule and what it means for a modular or prefab home.

There is published evidence that factory-built homes can meet these ratings. Sustainability Victoria documented four prefabricated modular homes under its 7 Star Homes Program rated between 7.0 and 7.7 stars.^[6] A star rating is a modelled result for the design, not a measurement of how the home performs once lived in.

Getting in and out §

Where a modular home is set on piers or a raised subfloor — to deal with slope, drainage or flood levels — the front door can sit well above the ground. For anyone using a pram, a walking frame or a wheelchair — now or later — the entry path matters as much as anything inside. How that interacts with step-free entry and hobless showers under the Livable Housing Design Standard is covered in the Livable Housing Design Standard and factory-built homes. Decks, retaining walls and landscaping around the house are covered in gardens and outdoor space with a modular home.

Bathrooms and kitchens §

In a volumetric modular home the bathroom and kitchen are normally kept whole within one module and fitted out in the factory, so waterproofing and pipework are covered before the module travels. Some projects instead use a separate, self-contained bathroom pod. What that means for waterproofing evidence and later repairs is covered in bathroom pods and factory-built bathrooms. Benchtop, cooktop and rangehood rules are covered in kitchens in modular homes.

The first year §

The first months after handover are when a modular home is most likely to show where it was joined. Walls and ceilings are lined in the factory and then transported, lifted and settled onto footings, and module junctions are natural places for that movement to show as cracking. Interior finishes in modular homes explains why and how finishes are judged.

Timing matters. Under Queensland's published guide, a crack visible from 1.5 m in ordinary light within the first 12 months is a defect; after 12 months only larger cracks are.^[7] Recording and reporting anything noticed in the first year, with photographs and dates, is the practical response. Other states publish their own guides.

Maintenance and later changes §

Routine maintenance and the question of who is liable for a fault at a module join are covered in warranties, defects and maintenance for modular homes. Extending or altering a factory-built home later, including what an engineer may need to check, is covered in warranties, maintenance and later changes to a prefab home.

Common questions §

Do modular homes have lower ceilings?

Not by rule. The NCC sets a 2.4 m minimum for habitable rooms other than kitchens in every house, modular or not.^[1] The actual height depends on the design and the transport height available on the delivery route.

Are modular homes noisy inside?

The NCC sets no sound insulation level for walls inside a single house.^[3] Overseas field tests in multi-unit modular buildings found doubled walls between modules can underperform, while floors generally met targets.^[4] Australian data for detached homes is not covered here.

Can a modular home achieve a 7-star energy rating?

Yes. Sustainability Victoria documented four prefabricated modular homes rated between 7.0 and 7.7 stars.^[6]

Is a crack after moving in normal?

Under Queensland's guide, a crack visible from 1.5 m within the first 12 months is a defect, so it should be recorded and reported rather than accepted.^[7]

What is not covered here §

No independent Australian study comparing the experience of living in modular and site-built homes — measured indoor temperatures, energy bills, internal noise levels or occupant satisfaction — is covered by the sources compiled here. Statements that modular homes are quieter, warmer, cooler or cheaper to run come from builders describing their own products and should be read as commercial claims.

The acoustic findings cited on this page are from multi-unit buildings in Canada and should not be applied directly to an Australian detached house. Internal ceiling heights achieved by particular Australian manufacturers are not covered.

Questions worth asking §

• What is the internal ceiling height in each room, and could it be higher on my route?
• Where do the module junctions fall, and do any run through bedrooms or living areas?
• Are internal walls insulated for sound, and which rooms share a wall?
• What is the design's energy rating, and which assessor produced it?
• How high will the floor sit above the ground, and how will the entry be reached?
• What is the process for reporting cracks or other defects in the first 12 months?

References §