OT/ SAH/ NDIS Compliance & Construction Guidelines

At Freedom Building Construction, we specialize in Complex Home Modifications (CHM). We bridge the gap between clinical necessity and Australian building standards, ensuring every modification is functional, safe, and fully compliant with AS 1428.1:2021 and NCC 2022.

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1. Bathroom & Sanitary Facilities

The bathroom is the most critical area for participant independence. We focus on Circulation Space—the clear floor area required for wheelchairs and commodes to maneuver.

• WC Pan Positioning: The center of the toilet pan must be 450–460mm from the adjacent side wall to allow for correct grab rail leverage.
• Seat Height: Must be between 460–480mm (AFFL) to assist with easier transfers.
• Grab Rails: Installed at a height of 800–810mm. We ensure solid internal blocking is used for all rail installations to meet high load-bearing requirements.
• Circulation Space: We ensure a clear floor space (typically 1900mm x 2300mm or larger) to allow for a 180° wheelchair turn.

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2. Door Widening & Access

A standard door is often the primary barrier to home access. We modify entries to meet the Continuous Accessible Path of Travel standards.

• Minimum Clear Opening: We provide a minimum 850mm clear opening. This typically requires a 920mm door leaf to account for the door's thickness when open at 90°.
• Latch Side Clearance: We strictly follow the 510mm (Pull side) and 300mm (Push side) clearance rules so users can operate handles without their wheelchair obstructing the door swing.
• Thresholds: We eliminate trip hazards using level thresholds or small internal wedge ramps (max 1:8 gradient for rises under 35mm).

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3. Ramps, Step Ramps & Landings

We calculate every millimeter to ensure ramps are safe for both self-propelling participants and power-chair users.

Threshold & Step Ramps

• Threshold Ramps: Max rise of 35mm, max length 280mm, and a max gradient of 1:8.
• Step Ramps: For rises up to 190mm, we use a max gradient of 1:10 with a maximum length of 1900mm.
• Step Ramp Landings: A landing of at least 1200mm is required at the top and bottom of every step ramp to allow a level "staging area" for the user.

Standard Ramps (Gradient 1:14)

• Landing Intervals: At a 1:14 gradient, a landing is mandatory every 9m. At 1:20, it is every 15m.
• Landing Dimensions: Straight landings must be 1200mm long. If the ramp turns 90°, a 1500mm x 1500mm landing is required.
• Edge Protection: We install 65mm high kerb rails to prevent wheelchair casters from slipping off the edge.

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4. Slip Resistance (P-Ratings & R-Values)

Surface safety is non-negotiable. We follow AS 4586 to ensure all modified surfaces provide adequate grip in both wet and dry conditions.

Area Type	Required Rating	Freedom Building Standard
External Ramps / Wet Areas	P5 (or R11)	High-traction broom finish or grit-reinforced coatings.
Internal Bathrooms / Entry	P4 (or R10)	Slip-resistant tiles or non-slip vinyl treatment.

• P5 / R11: Used for external ramps and paths where water is likely to be present (very high slip resistance).
• P4 / R10: Standard for internal wet areas like modified accessible bathrooms to prevent falls while remaining easy to clean.

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5. Other Essential Considerations

Luminance Contrast

We provide a 30% luminance contrast between door frames and walls, and on the leading edges of stairs, to assist participants with vision impairment.

Handrail Specifics

All handrails are installed between 865mm and 1000mm high. They must be continuous and include a 300mm horizontal extension at the top and bottom of the ramp to provide stability before the user enters the slope.

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Partner With a Compliance Expert

Are you an Occupational Therapist in Sydney looking for a builder who understands AS 1428.1:2021?

Contact Freedom Building Construction today for a technical site assessment.