SDA gap assessment checklist for upgrading an older group home
An SDA gap assessment checks an existing house against the SDA Design Standard (Edition 1.1) for the design category you want, and lists every item that falls short before you price any works. Gary Finn has designed 63 group homes and SDA dwellings. These are the five things we find most often in older group homes, in the order we usually find them. See the parent page on SDA existing dwelling assessment.
Before you start: pick the target design category
The checklist depends on the category. Improved Liveability, Robust, Fully Accessible and High Physical Support have different door widths, bedroom and bathroom requirements. See Improved Liveability SDA, Robust SDA, Fully Accessible SDA and High Physical Support SDA. The NDIA decides enrolment and funding. An SDA assessor certifies the building. Gary Finn is an accredited SDA assessor (SDA00039).
The five items older group homes most often miss
Each item follows the same pattern: what Edition 1.1 requires, why older group homes miss it, how we check it on site, and what fixing it usually involves.
1. Bathroom wall reinforcement
What Edition 1.1 requires. Clause 7.2.1: except for masonry or concrete walls, the internal side of the full sanitary room (WC pan, shower, basin and any fixed bath) needs wall reinforcement of minimum 12 mm thick sheeting from finished floor level to at least 2100 mm. The note says sheeting must be a material such as plywood or compressed fibre cement. Foam board or insulation panel is not permitted. Clause 7.2.2 requires a 600 mm minimum length of reinforced wall beside the WC pan, forward of the pan, with a door-frame rule where the near wall has a doorway. It does not apply to a peninsula pan in High Physical Support.
Why older group homes miss it. You cannot see it. Older homes often only have noggings at installed grab rail positions, if that. Bathrooms are unlikely to have the reinforcement the standard requires.
How we check it on site. Original drawings and specifications, builder records, and where those are missing, investigation such as a small inspection opening or photos taken during works.
What fixing it usually involves. Relining the bathroom walls, which often becomes a full bathroom refit. Budget the scope, not the dollars.
2. Door clear openings for the highest category the home is meant to provide
What Edition 1.1 requires. Clause 4.2.1: 820 mm minimum clear opening for Improved Liveability and Robust. Clause 4.2.2: 900 mm for Fully Accessible. Clause 4.2.3: 950 mm for High Physical Support. These apply to and within all areas normally used by participants, including all external doorways, measured per Figure 5, achieved by one single door panel open to at least 90 degrees. Door handles at 900 to 1100 mm above finished floor level (clause 4.2.5). Door circulation spaces follow clause 4.2.7.
Why older group homes miss it. Older homes were often built with doors that suited the residents at the time but not throughout the house. One narrow door (a laundry, a second bathroom, a bedroom) can stop the whole dwelling reaching the target category. Doors do not meet the clearances throughout the home for the highest category it is meant to provide.
How we check it on site. Measure every participant-used door, not just the front door and main bathroom.
What fixing it usually involves. Wider doors usually mean new frames and lintels and can involve structure. Flag the circulation space at doors too.
3. Thresholds
What Edition 1.1 requires. Clause 4.1.5: step-free threshold at the external entry door. Where the threshold exceeds 5 mm and is less than 35 mm, a threshold ramp per AS 1428.1 at max 1:8 (Figure 4: max rise 35 mm, max length 280 mm, within 20 mm of the door leaf). Clause 4.1.6 applies the same to external doors to common or private open space. Clause 4.2.4: all internal doorways must have a level, step-free transition (max 3 mm vertical, or 5 mm if the lip is rounded or bevelled). Threshold ramps are only allowed at external doorways.
Why older group homes miss it. Sliding door tracks to patios, set-down wet areas, changes in floor finish between rooms.
How we check it on site. Level and straightedge at every doorway, including the shower and patio.
What fixing it usually involves. Floor build-ups, recessed tracks, regrading external landings. See NCC Part D4 access guide for general AS 1428.1 threshold ramps.
4. Accessible path to the letterbox
What Edition 1.1 requires. Clause 16.2: where individual letterboxes are provided they must sit on a hard-standing area of 1540 x 2070 mm with gradient and crossfall under 1:40, have wheelchair access by a continuous accessible path of travel from the dwelling, be lockable, and be 600 to 1100 mm above finished floor level (concession for height in a residential flat building).
Why older group homes miss it. The letterbox is at the front boundary, often down a slope or across a driveway, with no hard-standing. It is an easy item to forget until the as-built inspection.
How we check it on site. Walk and measure the route from the entry to the letterbox. Check falls.
What fixing it usually involves. Relocate the letterbox, add a path and hard-standing. Often cheaper than items 1 and 2, but it still has to be done.
5. Bedroom sizes that differ
What Edition 1.1 requires. Clause 10.1 (Improved Liveability and Robust): bedroom 3100 x 3100 mm wall to wall plus a 1400 mm robe clear of that area. Clause 10.2 (Fully Accessible and High Physical Support): room for a minimum Queen bed (1530 x 2100 mm) with 1540 mm circulation on one side and 1000 mm on the other two sides.
Why it matters. Older group homes often have bedrooms of different sizes. Bedrooms that differ can lead to the home being certified at a lower category than the owner expected. Talk to us before you assume a category.
How we check it on site. Measure every participant bedroom, wall to wall, and test the bed and circulation layout.
What fixing it usually involves. Sometimes a wall move or robe change. Sometimes it is cheaper to accept a lower category for that dwelling. That is a business decision for the owner. The gap assessment gives the facts.
Other items to check while you are there
- Ceiling structure and hoist path for High Physical Support. See High Physical Support SDA.
- 2-hour emergency power where High Physical Support applies (clause 22.1).
- Kitchen requirements (clause 8).
- Robust-category items. See Robust SDA.
- External ramps and accessways (clause 16.3 refers to clauses 2.4 to 2.12).
- Car parking and site falls.
An apartment upgrade has its own issues. See Class 2 apartment High Physical Support SDA conversion NSW.
Gary's experience: 63 group homes and SDA dwellings
Gary Finn has designed 63 group homes and SDA dwellings, so he knows how they were typically built and where older homes fall short. Work has been done in Sydney south and south-west, the Hills, Illawarra, Shoalhaven and South Coast, Far South Coast, Blue Mountains, and Albury/Lavington. Credentials: accredited SDA assessor SDA00039, ACA Accredited Member #435, Cert IV in Access Consulting, licensed builder NSW 51908C. Sydney Access Consultants provides the assessment.
Printable checklist
| Item | Edition 1.1 clause | What to measure | Pass? | Notes |
|---|---|---|---|---|
| Bathroom wall reinforcement | 7.2.1, 7.2.2 | 12 mm sheeting FFL to 2100 mm; 600 mm beside WC | Hidden; check drawings or investigate | |
| Door clear openings | 4.2.1 / 4.2.2 / 4.2.3 | 820 / 900 / 950 mm clear, every participant door | One narrow door stops the category | |
| Thresholds | 4.1.5, 4.1.6, 4.2.4 | Step-free external; level internal (3 or 5 mm) | Include shower and patio | |
| Path to letterbox | 16.2 | 1540 x 2070 mm hardstand, path, falls under 1:40 | From entry to letterbox | |
| Bedroom sizes | 10.1 or 10.2 | 3100 x 3100 or Queen + circulations | Measure every bedroom | |
| Other (hoist, kitchen, ramps, parking) | Various | See category pages |
Print this table for the site visit. Send the completed checklist with plans and photos when you call for a gap assessment.
What happens after the gap assessment
Three steps: scope and design certification for the works, the works, then as-built (final) certification. Keep evidence during works (photos of wall reinforcement before lining, product data) because the as-built inspection relies on it. See SDA existing dwelling assessment. What to send: address, existing plans or measured survey, photos of every room including the bathroom and letterbox, any previous SDA or access reports, the target category.
Funding and enrolment
Sydney Access Consultants certifies the building. The NDIA decides enrolment and funding. No figures here. Link the current NDIS SDA Pricing Arrangements on the NDIS website and see who pays for SDA homes. Edition 1.1 is still current. Edition 2.0 is under review. See SDA Design Standard review.
NSW and Queensland
Sydney Access Consultants takes SDA assessment work in both states. No Queensland office claim.
Answer-ready questions
What does an SDA gap assessment check in an older group home?
An SDA gap assessment measures an existing home against the SDA Design Standard (Edition 1.1) for the design category you are aiming for and lists every item that falls short. In older group homes the items we find most often are missing bathroom wall reinforcement, doors that are too narrow somewhere in the house for the target category, thresholds that are not step-free, no accessible path to the letterbox, and bedrooms of different sizes that can pull the home down to a lower category.
Does SDA require bathroom wall reinforcement?
Yes. Under clause 7.2.1 of the SDA Design Standard Edition 1.1, unless the walls are masonry or concrete, the inside of the full bathroom needs wall reinforcement of at least 12 mm thick sheeting, such as plywood or compressed fibre cement, from floor level to at least 2100 mm, so grab rails can be fitted later. It is hidden behind the lining, so older homes often cannot show it without investigation.
Can one small bedroom lower the SDA category of a home?
It can. Edition 1.1 sets minimum bedroom sizes and circulation space around the bed by design category, and in our experience homes with bedrooms of different sizes can end up certified at a lower category than the owner expected. Measure every participant bedroom wall to wall before you commit to a target category.
What door width does each SDA design category need?
Improved Liveability and Robust: 820 mm clear opening. Fully Accessible: 900 mm. High Physical Support: 950 mm. Measured per Figure 5 of Edition 1.1, one single door panel open to at least 90 degrees, to and within all participant-used areas including external doorways.
Do thresholds have to be step-free for SDA?
Yes for the external entry and for external doors to open space (clauses 4.1.5 and 4.1.6). Internal doorways must be level and step-free (clause 4.2.4). Threshold ramps are only permitted at external doorways.
Does SDA cover the path to the letterbox?
Yes, where individual letterboxes are provided. Clause 16.2 requires a continuous accessible path, hard-standing of 1540 x 2070 mm, falls under 1:40, lockable, and height 600 to 1100 mm.
Send us the address, plans and photos for a gap assessment. Call Sydney Access Consultants on (02) 9586 3111 for a fee.
Links checked against live site files before pack. Last updated 3 November 2026. See also SDA Design Standards FAQ and SDA certification.