These three jobs come up more than any others when a home needs to work differently. They all look modest on paper. Then the quotes come back, and the range is wide enough to be confusing, and it’s hard to tell whether someone is overcharging or whether there’s something about your house you don’t know yet.
Usually it’s the second one. Here’s what sits behind the numbers.
Grab rails: Easy to use, but not always easy to fit
Most of these requests are for grab rails for bathroom use, at the shower and beside the toilet. A rail is a small object doing a serious job, and the thing it’s screwed into matters more than the rail itself.
The Australian Standard for access and mobility, AS 1428.1, sets out the familiar figures. Horizontal rails at the toilet and shower go 800 to 810 mm to the top of the rail above finished floor level. The rail itself is 30 to 40 mm in diameter, which is what a hand can close around properly. There’s a 50 to 60 mm gap between the rail and the wall, so fingers can wrap all the way round. The fixings have to withstand 1100 N applied from any direction.
One thing worth knowing: AS 1428.1 is written for public buildings. In a private home, it isn’t a legal requirement, and it’s used as a guide alongside an occupational therapist’s judgement about the person who’ll actually be using it. If someone is tall, or has a particular reach, or transfers from one side only, the right height is the one that works for them. The standard is a sensible starting point, not the final word.
Rails beside a bed are a slightly different conversation. Grab rails for beds are usually treated as assistive technology rather than building work, which means a different assessment and a different funding path. Your occupational therapist (OT) can point you in the right direction.
Why grab bar installation costs more than the rail
The rail is the cheap part. What drives the price is what’s behind the wall.
To hold 1100 N, a rail needs solid fixing: timber noggins, plywood blocking, or masonry. Plenty of older bathrooms have none of that where the rail needs to go. At that point, the job stops being “fit a rail” and becomes opening the lining, adding blocking, then making good. In a tiled wet area, that means cutting tiles, restoring the waterproofing membrane and finding tiles that match a 1998 bathroom, which is often the hardest part of the whole job.
Timeline-wise, grab rails for disabled access often go in within a day when the fixings behind the wall are sound. When the wall has to open, the clock is usually set by the waterproofing, which needs its own curing time before tiling can start.
Doorways: How hard is it to widen a doorway?
Door widening is the job with the widest spread in quotes, and it comes down almost entirely to whether the wall is carrying load. A non-structural internal doorway is often a few days of carpentry and making good. A load-bearing wall needs a lintel sized by an engineer, usually a building approval, and a longer program.
The first figure to understand is clear opening, because it isn’t the same as door width. The accessible benchmark is 850 mm of clear opening, measured from the face of the open door across to the doorstop. A standard 820 mm door leaf gives you roughly 780 mm once the leaf, stops and hardware are in the way. Getting to 850 mm usually means a 920 mm leaf, a wider frame, and therefore touching the wall rather than just swapping the door.
A few things decide how big that job becomes:
- What’s inside the wall. Power points, switches, water lines and wall bracing all have to go somewhere else, and those are extra trades.
- The wall type. A stud wall is straightforward. Solid masonry or brick veneer is a different scale of work.
- Floor coverings. Widening leaves a gap in the floor on both sides, and matching old flooring is rarely tidy.
- The approach. This one gets missed. The right width of doorway for wheelchair use doesn’t help if there’s nowhere to line up in front of it. A door at the end of a narrow hall, approached side-on, may need the circulation space sorted out as well.
That last point is worth raising early with your assessor. It’s much cheaper to discover it on a drawing than after the carpentry is finished.
Ramps: The rise decides nearly everything
Here’s a sum you can do yourself at the back door.
For ramps for wheelchair access over about 1900 mm long, the maximum gradient under AS 1428.1 is 1:14. That’s roughly 14 mm of ramp for every 1 mm you need to climb. Three typical steps are around a 450 to 600 mm rise, which works out at six to eight and a half metres of ramp. Landings are needed at the top and bottom, and again every 9 m on a 1:14 run, with each landing around 1500 mm long. Clear width is generally 1000 mm between handrails.
Shorter rises have their own, steeper allowances. A step ramp over a single small step and a threshold ramp at a doorway are both treated differently, with limits on rise and length. Editions of the standard differ on those numbers, so it’s worth confirming which applies to your job.
Run the sum on your own back step, and you’ll often find the ramp needs more yard than you have. That’s not a dead end; it’s just the point where the conversation widens: a different entry point, a regraded path, a platform lift, or a shorter ramp to a side door.
Ramps for elderly use aren’t always the same brief, either. Someone walking up with a frame may be better served by a gentler, shorter run with rails on both sides than by a long compliant ramp designed around an occupied wheelchair. Say who’s using it and how, and the design follows.
Materials shape both cost and timeline. Modular aluminium can go in quickly and comes out again if the need changes. Timber suits a deck or raised landing and sits comfortably with most homes. Concrete lasts longest and takes the longest. Ramp installation beyond a low height usually needs building approval, and handrails and edge protection come with it.
The three jobs side by side
| Grab rails | Doorway widening | Ramps | |
| Typical on-site time | Under a day with sound fixings; longer if the wall opens | A few days non-structural; longer if load-bearing | Days for modular; weeks for built in place |
| Approval usually needed | Generally none | Likely if load-bearing | Often, depending on height and location |
| Biggest cost driver | What’s behind the wall, and wet-area reinstatement | Whether the wall carries load | The rise, and the room to fit the run |
| Easy thing to miss | Tile matching | Circulation space at the door | Landings |
Before you compare quotes
Two things make quotes comparable. Ask what each one assumes about what’s behind the wall, as that’s where the variation usually lives. And check that each is pricing the same finished result, not the same object.
If you rent, or the home is under a body corporate, start the consent conversation now rather than once you’ve chosen a builder. It runs on its own timeline, and it’s the most common reason a well-organised project sits still.
Talk it through before anyone drills.
You don’t need to have it all worked out. A short conversation with a builder early, ideally alongside your assessor, usually saves more than it costs.
Mathiou Services is a registered NDIS provider and a licensed builder, QBCC 1202203 and NSW Fair Trading 273391, working across Queensland and Northern NSW. We’re regularly asked to look at NDIS home modifications at the drawing stage, when it’s still easy to change the plan, and we work on the same three jobs in independent and supported living homes where several people need the result to work for them.
If you’d like to walk through what you’re considering, get in touch or call 1300 363 423. No obligation, and nothing to decide on the spot.