Repair Systems — Roofing Defects
Aluminium roof access hatch systems for strata buildings
Aluminium roof access hatches provide code-compliant, weather-tight access to flat and low-pitched roofs in Class 2 strata buildings for maintenance personnel. Units from Milcor and Gorter comply with AS 1657 fixed platforms and stairways requirements and include security locks, gasket seals and integral lifting handles.
What are aluminium roof access hatch systems?
Aluminium roof access hatches provide code-compliant, weather-tight access to flat and low-pitched roofs in Class 2 strata buildings for maintenance personnel. Units from Milcor and Gorter comply with AS 1657 fixed platforms and stairways requirements and include security locks, gasket seals and integral lifting handles.
Product Reference
3 products — aluminium roof access hatch systems — scroll to view all
Milcor Style AL
Single-leaf aluminium roof access hatch — spring assist — EPDM weatherseal
System Description
The Milcor Style AL is a single-leaf aluminium roof access hatch with an integral aluminium curb and flush aluminium cover, available in square sizes from 600×600mm to 1200×1200mm. The continuous piano hinge provides a full-width hinge line that distributes the opening load evenly and is more durable than point-hinge alternatives in high-frequency access applications. Compression spring assist reduces the effective opening force required by the maintenance operative — a compliance consideration for AS 1657 access requirements in Class 2 strata buildings. The EPDM compression gasket on the curb head provides a weathertight seal between the cover and curb that maintains performance over multiple open/close cycles. The padlockable latch allows the building manager to control roof access — a standard provision in strata buildings where roof access must be restricted to authorised personnel. The flush lid design avoids protruding hardware that could create a trip hazard in trafficked roof areas. The Style AL curb is designed for direct installation to the structural roof deck — on flat membrane roofs, the waterproofing must be terminated to and over the base of the curb by a licensed waterproofer. Milcor products are distributed in Australia through roofing and commercial building supply channels — confirm current stock and lead times with the local distributor.
Technical Properties
- Single-leaf aluminium hatch — 600–1200mm square — aluminium curb and cover — flush lid design
- Continuous piano hinge — full-width hinge for even load distribution — suitable for high-frequency access
- Compression spring assist — reduces opening force — assists AS 1657 access compliance for maintenance personnel
Limitations
- Waterproofing termination to curb base is NOT supplied — a separate licensed waterproofer must design and install the membrane termination at the curb
- Spring assist reduces but may not eliminate the need for a fixed access ladder — confirm AS 1657 access requirements for the specific building configuration
- Padlock is NOT supplied with the unit — confirm padlock specification and key management protocol with building manager before ordering
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Gorter HAL Roof Hatch
Single-leaf aluminium roof hatch — stainless hardware — concealed hinge
System Description
The Gorter HAL Roof Hatch is a single-leaf aluminium hatch with a concealed hinge design, available in square sizes from 600×600mm to 900×900mm, suitable for flat and curved roof applications in Class 2 strata buildings. The concealed hinge avoids exposed pivot hardware that could corrode in coastal and marine environments — a practical advantage for strata buildings in coastal Australian locations. All hardware is specified in 304 stainless steel, providing significantly better corrosion resistance than zinc-plated or painted mild steel hardware used in budget hatch products. The EPDM weatherseal on the curb head maintains a weathertight seal when the hatch is closed. The HAL is designed for installation on both flat membrane roofs and curved standing seam or profiled metal roofs — the curb base geometry can be factory-set to the specific roof pitch and profile, which eliminates the need for site-made wedge curbs. Gorter is a European manufacturer with an Australian distribution presence — confirm current stock, lead times, and the local distributor before specifying. On flat membrane roofs, the waterproofing must be terminated to and over the base of the curb by a licensed waterproofer. The HAL does not include a spring assist mechanism as standard — confirm the opening assistance specification with Gorter Australia if spring assist is required for AS 1657 compliance.
Technical Properties
- Single-leaf aluminium hatch — 600×600 to 900×900mm — concealed hinge — no exposed pivot hardware
- 304 stainless steel hardware — improved corrosion resistance for coastal and marine strata applications
- EPDM weatherseal — weathertight when closed — maintains seal integrity over repeated open/close cycles
Limitations
- Spring assist is NOT standard on HAL — confirm if spring assist is required for AS 1657 compliance and specify accordingly
- Maximum size 900×900mm — for larger hatches up to 1200×1200mm, the Milcor Style AL or Bilco E-50TB may be more appropriate
- Waterproofing termination to curb base is NOT supplied — a separate licensed waterproofer must design and install the membrane termination
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Bilco E-50TB
Aluminium escape-rated roof access hatch — counterbalance spring — double-sealed
System Description
The Bilco E-50TB is a single-leaf aluminium roof access hatch rated as an escape hatch, available in the standard 24"×36" (610×914mm) size. It is classified by Bilco as an egress unit — a distinction from standard access hatches — and is UL listed, which provides a recognised third-party compliance certification relevant where an egress-rated hatch is required in the building consent documentation. The double-seal design — comprising a primary weatherstrip and a secondary interior seal — provides superior weather protection compared to single-seal products and reduces air infiltration into the conditioned space below. The compression spring counterbalance mechanism allows the hatch to open and stay open without manual effort after the initial lift — a significant operational advantage for emergency egress and for maintenance personnel working alone on the roof. The optional exterior ladder provision allows integration of a fixed access ladder to AS 1657 for strata buildings where roof access is required as a means of egress or fire service access. On flat membrane roofs, the waterproofing must be terminated to and over the base of the curb by a licensed waterproofer. The Bilco E-50TB follows a different compliance path to the Milcor Style AL and Gorter HAL — the UL listing and escape rating make it appropriate where a higher compliance standard is specified or required by the building consent authority.
Technical Properties
- Single-leaf aluminium escape-rated roof access hatch — 610×914mm standard — UL listed
- Double-seal design — primary weatherstrip and secondary interior seal — reduced air infiltration and superior weather protection
- Compression spring counterbalance — hatch opens and stays open without manual effort — suitable for emergency egress
Limitations
- Standard size is 610×914mm — confirm this size meets the AS 1657 clear opening requirement for the specific building configuration
- UL listing is a US certification — confirm Australian building consent acceptance of UL listing as evidence of compliance with the building surveyor before specifying
- Waterproofing termination to curb base is NOT supplied — a separate licensed waterproofer must design and install the membrane termination on flat roof applications
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
System Comparison
Side-by-side comparison of aluminium roof access hatch systems. Confirm all product selections against the current manufacturer TDS before specifying.
| Product | Size range | Spring type | Weatherseal | Hardware |
|---|---|---|---|---|
| Milcor Style AL | 600–1200mm square | Compression spring assist | EPDM compression gasket | Aluminium / padlockable latch |
| Gorter HAL | 600×600 to 900×900mm | Confirm with Gorter — not standard | EPDM weatherseal | 304 stainless steel — concealed hinge |
| Bilco E-50TB | 610×914mm standard | Compression spring counterbalance | Double-seal — primary + secondary | Aluminium — UL listed hardware |
Do not confuse aluminium roof access hatch systems with:
- Insulated roof access hatches — where NCC Section J compliance is required in conditioned spaces, an insulated hatch with thermal break and airtight seal is required — listed separately on the insulated hatch systems page
- Fire-rated access hatches — standard aluminium hatches do not have a fire resistance rating — confirm fire resistance requirements with the building surveyor before specifying a non-rated aluminium hatch
- Skylight curb-mount units — aluminium roof access hatches are access and maintenance hatches, not glazed skylights — the Velux FCM and similar flat roof glazed units are a different product category
- Roofing access ladders — the access hatch provides the weather-tight opening — a separate fixed ladder to AS 1657 may be required and must be specified separately
- Smoke ventilation hatches — smoke ventilation systems are a separate life safety product category with different standards and activation requirements — do not substitute a standard access hatch for a smoke ventilation hatch
Disclaimer
This page provides general technical information only. Final product selection must be confirmed against the current manufacturer technical data sheet, AS 1657 requirements for the specific building configuration, building surveyor requirements, and the building consent conditions. Confirm load rating, clear opening size, and waterproofing at curb requirements with the relevant consultants before ordering. Do not rely on this reference as a substitute for professional engineering or building consultant advice.