Ramp Calculation and Construction for Wheelchair and Senior Care Access
A wheelchair ramp at the wrong slope is not a ramp — it is a fall risk. The right ramp for a senior or a disabled user is shallow enough to be pushed without strain, wide enough for the wheelchair, edged for safety, and broken up by level landings on long runs. This guide is a contractor's view of how we size and build ramps for Singapore homes and small entrances, with reference to the BCA Code on Accessibility in the Built Environment 2019.
The rise/run idea in one sentence
Ramp slope is the ratio of the height you have to climb (rise) to the horizontal length of the ramp (run). A 1 : 12 ramp gains 1 unit of height for every 12 units of length — for a 100 mm step that is 1.2 m of ramp, which most wheelchair users can self-propel with effort. Steeper than that, and the user needs help; gentler than that, and the ramp feels effortless. The Ramp Rise / Run reference chart that many home-equipment suppliers publish shows the same idea visually, with slopes around 4.8° corresponding to 1 : 12 and steeper angles only suitable for portable ramps or unoccupied scooters.
Singapore reference gradients (BCA Code 2019, Table 5)
For ramps in the built environment, BCA gives this gradient/length pairing as a reference. We use it as the upper bound, then choose a gentler gradient when the user, the wheelchair or the surface call for it.
| Gradient of ramp | Maximum horizontal run between level landings |
|---|---|
| 1 : 12 | 6 m |
| 1 : 14 | 9 m |
| 1 : 15 | 11 m |
| 1 : 20 | 15 m |
| 1 : 25 or gentler | 18 m (no intermediate landing required) |
Width, landings and edge protection
- Width: minimum clear ramp width 1200 mm in the public Code. For a private entrance ramp we still aim for 900 mm clear at the narrowest point, which suits standard manual wheelchairs.
- Landings: 1500 mm or more of level platform at the top, at the bottom, and wherever the ramp turns direction.
- Edge protection: a kerb or upstand at the side of any ramp that is not against a wall, to keep wheels from running off.
- Handrails: tubular section 32–50 mm diameter, 40–60 mm clear of the wall, slip-resistant and continuous along the run. A second lower handrail is helpful for shorter users or children.
- Cross-fall: the ramp should not slope sideways more than 1 : 40, otherwise the wheelchair tracks off-line.
Surfaces and drainage
Ramp surfaces must be slip-resistant in both dry and wet conditions. The BCA Code references slip resistance grading in Appendix F — in practice we specify a finish with a documented wet pendulum value, lay drainage so water sheds off the side rather than running down the ramp, and avoid open-jointed pavers which can catch a wheelchair caster or the tip of a walking aid.
Practical contractor process
- Measure the rise honestly. The vertical distance from finished floor outside to finished floor inside, including the threshold lip.
- Choose a gradient. Default to 1 : 12 only if the user is independent and capable; 1 : 15 or 1 : 20 is kinder, especially with a caregiver pushing.
- Convert to length. Run = rise × gradient denominator. For a 200 mm rise at 1 : 15, the run is 3.0 m.
- Add landings. 1500 mm at top and bottom, plus an intermediate landing if the run exceeds the figure in the table.
- Check the door. The bottom landing must clear the door swing; the top landing must allow a wheelchair to stop, square up and reach the handle without rolling backwards.
- Choose a finish. A slip-resistant tile, a textured concrete topping or a rubberised ramp surface — matched to the surrounding floor for visual continuity.
When a permanent ramp is not feasible
HDB common areas, short driveways and small entrances sometimes cannot accommodate a 1 : 12 permanent ramp. In those cases we look at:
- A portable threshold ramp for one-step entries, sized to the actual rise.
- A foldable channel ramp kept by the door for kerb hops with caregiver assistance.
- A platform lift where the rise is too great for any reasonable ramp length.
Where this advice fits
The figures above are a planning reference, not a universal rule for every private home. Final ramp design has to be checked against the actual site, the applicable local accessibility rules and the user's ability. For HDB common-property ramps and any public-facing work, the BCA Code is the controlling reference and approvals must be obtained where required.
Related services
References
- BCA Code on Accessibility in the Built Environment 2019 — Chapter 4 (Ramps, Handrails and Grab Bars), Table 5 (Gradient and Length of Ramps), Appendix F (Slip Resistance of Floor Finishes), Appendix B (Design Guidelines for Older Persons).
- Ramp Rise/Run reference chart, MobilityBasics.ca — visual cross-reference of slope angles.
- LifeSG senior care services guide — context for senior care services in Singapore.