Tiny Home Foundations Australia: Stumps, Piers & Slabs

The short answer

A fixed tiny home, prefab cabin or modular dwelling needs a support system designed for the building and the block. Stumps, concrete piers, screw piles and slabs can all be workable, but none is the default answer for every project.

Start with the building's point loads and tie-down requirements, then check the site's soil, slope, fill, drainage, wind exposure and access. The support system should be selected and documented by the parties responsible for the building and foundation design, with suitable engineering input, before you treat the site-work price as firm.

A tiny house on wheels is different. Manufacturer-specified levelling legs or temporary supports may form part of its placement instructions, but they do not automatically turn it into an approved fixed dwelling or replace any support, anchoring or approval requirements for the intended use.

This guide is general information, not structural, geotechnical, building or planning advice. Confirm the design with the builder, structural engineer, geotechnical consultant, certifier or building surveyor, and the relevant authority for your site.

Quick comparison

Support type	Where buyers commonly consider it	Questions that decide whether it fits
Stumps with pad footings	Raised floors, sloping ground and projects needing access below the floor	What material, bracing, pad footing, corrosion protection and tie-down design are specified?
Concrete piers	Concentrated support points for a raised structure or module	How are pier size, depth, spacing, reinforcement and connection to the building determined?
Screw or helical piles	Sites where reduced excavation or a quick installation may be useful	Has the pile system been designed for the soil, loads, corrosion exposure, uplift and lateral forces?
Concrete slab	Flatter sites, integrated floor systems and projects where a ground-level platform suits the design	What excavation, fill, drainage, reinforcement, termite treatment and service penetrations are included?
Proprietary steel supports	Some transportable cabins and modular systems with a documented connection detail	Are they permanent structural supports, who designed them, and what footings or anchors sit below them?

This table is a shortlist prompt, not a design guide. A system that looks simple in a brochure can change once a soil report, survey or structural design is available.

“Stumps” is not a complete specification

Searches for tiny-home stumps often make the job sound like a product purchase: choose a height, set out a few supports and place the home on top. For a fixed dwelling, the useful questions go further.

Ask for a drawing or schedule that identifies:

the number and position of support points
the design loads at those points
stump or pier material and dimensions
pad footing size and founding depth
bearer, chassis or module connection details
bracing against sideways movement
tie-down or uplift resistance
corrosion and termite-management details where relevant
finished floor level and minimum underfloor clearances
responsibility for certification and inspection

The Australian Building Codes Board's current Housing Provisions include site classification, foundation requirements and specific stump-footing provisions. They also place limits on when the prescriptive provisions can be used. That is why copying a footing detail from another tiny home—or using the smallest table value without knowing the supported area and soil—is not a sound comparison method.

Get the site information before the “fixed” quote

The foundation quote is only as reliable as the information behind it.

Soil and foundation data

A soil or geotechnical report helps identify the site's classification, bearing conditions, reactive soil, fill and other constraints. The Housing Provisions require the foundations where footings and slabs will sit to be classified under AS 2870. For Class H, E or P sites, they direct designers to AS 2870 for design and construction rather than relying only on Part 4.2.

Victoria gives buyers a particularly clear example of why timing matters. For Victorian domestic building work covered by that guidance, Consumer Affairs Victoria's foundation guidance says the builder must obtain foundation data before the building contract is signed, and explains that slope and soil type can affect design and cost. The exact legal and contracting rules differ elsewhere, but the practical lesson travels well: do not compare foundation allowances as if the block has already been understood when it has not.

Survey, levels and drainage

A soil report does not replace a survey or drainage plan. The team may need to know the site's levels, boundaries, easements, existing services, retaining walls, trees, filled areas and the proposed finished floor level.

Water also matters. A pad or pier can be structurally adequate on paper and still sit in a poor location if stormwater is directed under the home or the access track erodes around the supports.

Building loads and connection details

The foundation designer needs information from the building supplier. For a modular home, that can include concentrated module loads, lifting-frame or chassis details, connection points and the tolerance required when several modules are joined. For a tiny house on wheels, the manufacturer should state the safe levelling and support method rather than leaving the owner to improvise under the chassis.

Stumps and piers: where the detail matters

A raised system can be useful on a sloping site because it may reduce broad excavation and can leave room to run or inspect services. It can also make floor-level changes easier to manage.

That does not mean it is automatically cheaper. A steep or difficult site may need deeper footings, bracing, engineered retaining or drainage work, more complex stairs and landings, and safer access for the installation crew. Exposed steel also needs a suitable corrosion strategy, especially near the coast or in aggressive ground conditions.

Clarify the language in the quote. Builders and suppliers may use “stump”, “pier”, “post” and “support” differently. What matters is the documented load path from the home, through its bearers or chassis and connections, into the footing and founding material.

Screw piles: fast installation is not the whole decision

Builders may propose screw or helical piles where reduced excavation or installation speed is useful. Treat those benefits as project-specific until the engineer and installer have checked the site.

They still need design. Ask who determines the pile type, shaft and helix size, installation depth, design capacity, corrosion allowance, lateral restraint and connection to the home. Also ask what installation records or verification the contractor supplies.

If a quote says only “screw piles included”, it is not yet comparable with an engineered slab or pier quote.

Slabs: predictable platform, earlier decisions

A slab can provide a level platform and may form part of the finished floor system. On a straightforward site, it can also make installation access and perimeter finishing easier to understand.

The trade-off is that services, penetrations, finished floor levels and module connection points need to be coordinated early. Excavation, imported or removed material, controlled fill, drainage, reinforcement, termite management and curing time can sit outside an advertised home price.

Ask whether “slab included” means a complete engineered slab for the actual site or a standard allowance based on assumed soil and levels.

Separate the three scopes in every quote

Foundation surprises often come from three different jobs being treated as one line item.

Investigation and design: survey, soil or geotechnical report, structural engineering and certification documents.
Site works and foundation construction: clearing, excavation, fill, drainage, footings, piers, piles, slab, bracing and inspections.
Placement and connection: crane or transport setup, levelling, module-to-foundation connection, tie-downs, service connections, stairs, decks and finishing around the base.

Mark each item as included, excluded, provisional or supplied by another contractor. Record who coordinates the hand-off. A builder may supply the home while a local contractor supplies the foundation; that can work well, but only when the drawings, tolerances, programme and warranty responsibilities line up.

For the wider project, use the site preparation checklist and delivery and installation checklist alongside this guide.

A practical pre-contract checklist

Before paying a substantial deposit, ask:

Has the exact building location been surveyed?
Is the soil or foundation information current and taken from the relevant part of the block?
Has the foundation designer received the building's actual loads and connection details?
Does the quote cover slope, rock, fill, drainage and access assumptions?
Are wind, flood, bushfire, coastal corrosion or termite conditions relevant?
Who supplies the engineer's drawings and certification?
Who arranges footing or foundation inspections?
Are temporary supports clearly separated from permanent works?
Who is responsible if the constructed supports do not match the delivered module?
Are stairs, landings, skirting, underfloor screening and service penetrations included?
Does the approval pathway treat this as a fixed dwelling, a secondary dwelling, a cabin or a movable structure?
What evidence will the certifier, insurer or lender expect at handover?

The questions to ask a tiny home builder guide covers the broader company, contract and documentation checks.

A worked comparison without false precision

Consider two buyers looking at the same compact prefab cabin.

Buyer A has a relatively flat block, verified founding conditions, clear truck and concrete access, and services positioned before the slab is detailed. Buyer B wants the cabin farther down a sloping rural block with fill, uncertain drainage and limited machinery access.

The cabin price may be identical. The suitable foundation, investigation work, installation method and risk allowance may not be. A national “cost per stump” or “average slab price” would hide the issue that matters: whether the support system and quote have been designed around the actual block and building.

Use the tiny house cost guide or modular home cost guide to place the foundation scope inside the total project budget.

Current code and approval context

The ABCB's general NCC guidance describes NCC 2022 Amendment 2 as the current national edition and notes that jurisdictions may consider adopting NCC 2025 from 1 May 2026. Adoption and transition arrangements are set by each state and territory, so confirm which edition and local variations apply to the project rather than relying on the date printed on a generic detail.

The NCC Housing Provisions on footings, slabs and associated elements are a useful source for understanding why site class, supported area, material, bracing and bearing conditions matter. They are not a substitute for project documentation.

Builder and directory next steps

Once the site information is ready, compare builders that can explain both the home and its hand-off to local site trades:

For a more finished, design-led prefab cabin or tiny home, Zinc Studio is a premium option to shortlist. Ask Zinc Studio—or any builder—to confirm the site-information requirements, foundation scope, engineering hand-off, delivery, approvals support, pricing and current service area in writing.

FAQ

Are stumps suitable for every tiny home?

No. Suitability depends on the building loads, support layout, soil, slope, wind and uplift, bracing, corrosion exposure, approval pathway and the connection between the home and supports.

Do tiny houses on wheels need foundations?

A THOW uses its engineered chassis and manufacturer-specified levelling or support system. Do not assume generic blocks, jacks or the jockey wheel are suitable for long-term support. Long-term placement can still raise anchoring, stability, service, safety and approval questions, and temporary supports are not automatically an approved fixed-dwelling foundation.

Should the builder or owner arrange the soil test?

That depends on the contract and jurisdiction. The important point is that the relevant designer and builder receive reliable site information before the foundation price and design are treated as final. In Victoria, specific foundation-data rules apply before signing a domestic building contract.

Is a slab cheaper than piers or screw piles?

There is no dependable national answer. Site access, excavation, slope, soil, fill, drainage, engineering, concrete, steel, service penetrations and installation sequencing can reverse a simple headline comparison.

Can I reuse a foundation detail from another model?

Do not assume so. A different module length, floor layout, chassis, roof load, tie-down arrangement or support spacing can change the design loads. Ask the builder and engineer to identify the detail that applies to the exact model and site.

Sources and last updated

Primary sources checked 21 July 2026:

Last updated 21 July 2026. Confirm current code adoption, local requirements and project-specific engineering before relying on this guide.

Tiny Home Foundations in Australia: Stumps, Piers and Slabs