The Four SDA Design Categories Explained
Improved Liveability, Fully Accessible, Robust and High Physical Support. What each one means, who it suits, what evidence supports each, and what to do if you are approved for the wrong one. Written by the occupational therapists who prepare the reports.
There are four categories, and you do not choose one
The design category describes the features a dwelling is built with. Which one applies to you is a clinical question, decided by the NDIA on your evidence.
Improved Liveability
Housing with better physical access and a layout that is easier to understand and move through. Think clear sightlines, good lighting, wayfinding cues and a plan that supports a predictable routine.
Usually relevant where the barrier is understanding and navigating a space rather than physically moving through it.
Fully Accessible
Designed throughout for a person with significant physical impairment: level entry, wider doorways and corridors, accessible bathroom and kitchen, and circulation space for a wheelchair.
Generally suits someone who uses a wheelchair and can transfer independently or with limited assistance.
Robust
Resilient, low-stimulation housing built to withstand impact and reduce risk. Impact-resistant wall linings, secure windows and doors, laminated glass, durable fixtures and considered exits.
Usually relevant where behaviours of concern mean a standard dwelling is unsafe or repeatedly damaged.
High Physical Support
Fully accessible housing with additional clinical features: structural provision for ceiling hoists, emergency power backup, home automation and capacity for assistive technology and equipment.
The highest funded category, and the one with the strictest evidence requirements. Generally for people who cannot transfer independently and rely on powered equipment.
Source: Specialist disability accommodation, NDIS. Requirements within each category can change; confirm current detail with the NDIA.
When the barrier is understanding a space, not moving through it
Improved Liveability housing is built for people whose impairment is sensory, intellectual or cognitive. Its features are less visible than a ramp, which is precisely why this category is the most often under-recognised of the four.
It covers clear lines of sight through the dwelling, good natural and artificial lighting, layouts that make it obvious where things are, wayfinding cues, and reduced visual and acoustic clutter. The aim is a home that supports a predictable routine rather than creating confusion or sensory overload.
If somebody can physically manage a standard house but becomes disoriented, overwhelmed or unsafe in it, this is usually where the evidence points.
What trips people up: because the person walks, cooks and showers unaided, a superficial assessment records them as independent. The difficulty is not the task, it is the environment they are performing it in. That has to be observed and written down specifically, not summarised as needing support.
Built throughout for significant physical impairment
Fully Accessible housing is designed end to end for significant physical impairment: level or ramped entry, wider doorways and corridors, circulation space to turn a wheelchair, an accessible bathroom with appropriate clearances, and a kitchen usable from a seated position.
It generally suits somebody who uses a wheelchair and can transfer independently or with limited assistance. Where a person cannot transfer independently and relies on powered equipment, the evidence usually points to High Physical Support instead.
What trips people up: assuming a standard modern home is close enough. It rarely is. Doorway widths, the turning circle in a bathroom and the approach to a kitchen bench either work or they do not, and those are measurements, not impressions. An assessment that does not measure is not evidence.
Resilient housing where a standard dwelling is not safe
Robust housing is built to withstand impact and to reduce risk to the resident, to the people supporting them and to others nearby. Impact-resistant wall linings, laminated glass, secure windows and doors, durable fixtures, and careful attention to exits and sightlines for support workers.
It is also designed to be low-stimulation, because reducing what triggers escalation is part of what makes it work, rather than simply making the building harder to damage.
This category is usually relevant where behaviours of concern mean a standard dwelling is repeatedly damaged or genuinely unsafe. Evidence typically includes behaviour support information alongside the functional assessment.
What trips people up: describing behaviour without linking it to the environment. The question is not how the person behaves, it is what in a standard dwelling contributes to it and what a Robust design would change. That link has to be made explicitly.
Accessible housing with clinical infrastructure built in
High Physical Support housing has everything a Fully Accessible dwelling has, plus infrastructure for high-intensity physical support: structural provision for ceiling hoists, emergency power backup, home automation for people who cannot operate standard controls, and capacity for the equipment that goes with very high support needs.
It attracts the highest funding of the four categories and, correspondingly, the strictest evidence requirements. It generally applies where a person cannot transfer independently and depends on powered equipment and hands-on support.
What trips people up: stating that support needs are high without documenting the mechanics. What is needed is specific, observed detail: how transfers actually happen, what equipment is involved, how many people, what positioning is required, and what happens in a power outage.
What your report has to establish for each category
This is the part the housing providers cannot tell you, because they do not write the reports. Each category turns on a different question, and a report that answers the wrong one delays the decision.
| Category | What must be established | What that looks like in evidence |
|---|---|---|
| Improved Liveability | That the barrier is cognitive, sensory or intellectual rather than physical | Observed difficulty navigating or understanding a space, getting lost or disoriented, sensory responses to noise and light, and what a clearer layout would change. |
| Fully Accessible | That wheelchair access is required throughout, and that you can transfer | Measured circulation space, doorway widths that fail, bathroom and kitchen usability from a seated position, and observed independent or assisted transfers. |
| Robust | That a standard dwelling is genuinely unsafe or repeatedly damaged | Documented incidents, the environmental triggers involved, behaviour support information, and why standard fixtures have not held up. |
| High Physical Support | That you cannot transfer independently and depend on powered equipment | Hoist and transfer requirements, positioning needs, equipment already in use, clinical support delivered at home, and the consequences of power loss. |
Across all four, the same principle applies: observed and specific beats described and general. “Requires assistance with transfers” is a sentence. “Requires two people and a ceiling hoist for all transfers, with equipment currently unable to be positioned in the bedroom because of a 720mm doorway” is evidence.
Category and building type are two separate decisions
People routinely conflate these. The design category describes what is built into the dwelling. The building type describes what kind of dwelling it is, and therefore how many people you live with.
| Building type | What it means |
|---|---|
| Apartment | A self-contained unit within a larger residential building. |
| Duplex, villa or townhouse | Separate but semi-attached dwellings on a single title or strata, including stand-alone villas. |
| House | A detached low-rise dwelling with a garden or courtyard, housing up to three residents. |
| Group home | A house with four or five bedrooms, shared with other residents. |
An SDA funding decision generally specifies both, along with the number of bedrooms and residents, the location, and whether on-site overnight assistance is included. In practice the building type often matters more to quality of life than the design category does, because it determines whether you live alone, with two others, or in a group home of four or five. It is worth being explicit about that preference and the functional reasons behind it, rather than leaving it to be inferred.
What to do if you are approved for the wrong category
This happens, and it is recoverable. It is also much easier to prevent than to fix.
- 1Work out what the decision was actually based on. Usually the evidence answered a general question about support needs rather than the specific question the category turns on.
- 2Request an internal review. Generally available within three months of receiving the decision in writing. A different NDIA delegate reconsiders, and you can submit new evidence as part of it.
- 3Get evidence that addresses the gap. This is the step that matters most. A review with the same report attached tends to produce the same answer.
- 4External review if needed. If you are still not satisfied after the internal review, an external review at the Administrative Review Tribunal is generally available, usually within 28 days of the internal review decision.
Source: Guide to decision reviews, NDIS. Timeframes and processes change; confirm the current position with the NDIA, your planner or an advocate. This is general information, not legal advice.
Where SDA sits alongside SIL, ILO and MTA
SDA is one of several home and living supports, and the terms get used interchangeably when they should not be.
SDA
Funds the dwelling: purpose-built or heavily modified housing. The funding attaches to the property, so you can change support providers without moving.
SIL
Funds the people: help and supervision with daily tasks, most often in shared living with rostered support. Separate decision, separate evidence.
ILO
Individualised Living Options: a support arrangement designed around how you want to live, rather than a staffed shared house. Often the better fit for people who want support without group living.
MTA
Medium Term Accommodation: a shorter-term arrangement for when you are ready to leave your current housing but your long-term home is not yet available.
Many participants need more than one of these, and some need none. If you are still working out which applies, our SIL versus SDA guide compares the two reports directly, and our ILO assessments page covers the alternative to shared supported living.
SDA design categories: common questions
How many SDA design categories are there?
Can I choose my SDA design category?
Which SDA category has the highest funding?
What if I am approved for the wrong category?
Can my design category change later?
What if my needs sit across more than one category?
Is the design category the same as the building type?
Are the SDA design categories changing in 2026?
Need evidence for an SDA request?
Our AHPRA-registered occupational therapists assess at home across Greater Sydney and address the design category question directly, with the reasoning on the page.
Make a referral or call 1300 316 664Which design category the evidence supports is a clinical judgement, made the same way we make every other. Read our full assessment methodology, including the evidence standard every recommendation is written to.