September 26, 2019

Building Regulations for Roof Access Hatch

What is a roof access hatch?

A roof access hatch is an opening on a roof that can be used as an emergency exit from a building, or as a means of access for maintenance workers servicing any kind of roof-mounted equipment.

The hatches provide access to roofs via interior ladders or stairs. Industrial buildings with very high ceilings may be more likely to have ladder access, whereas other buildings like schools or offices would be more likely to have a set of stairs.

Roof hatches can also be used when installing or removing larger pieces of equipment from a building. Depending on the task required, a hatch may have either one smaller cover or door, or two in the case of large industrial facilities where equipment is being loaded in and out.

There are a number of safety regulations and building code requirements in Ontario relating to the use of roof access hatches. Hatches must meet the standards required by the National Building Code (Canada) and the Occupational Health and Safety Administration (OSHA) in the United States. Let’s take a look at some of the basic requirements.

Roof access hatch safety measures

Roof access hatches can be installed on flat roof surfaces, the maximum incline being 30 degrees.

The hatches should also be insulated well to prevent frost and condensation accumulation. Most roof access hatches are made of galvanized steel or aluminum.

It’s important that the hatches are relatively lightweight and easy to handle. They must be resistant to fire and be able to sustain explosions. Additionally, some situations require the hatch to be made of specific materials. In a highly corrosive environment such as a chemical plant, a hatch must be made of stainless steel or copper. Heritage buildings may require the use of copper to maintain the appropriate aesthetic.

All roof access hatches must have a guardrail. Roof surfaces can become slippery and icy, especially in periods of inclement weather.
A guardrail is an important safety measure, especially when accessing a rooftop during inclement conditions. Additionally, a support bar needs to be installed right near the exit point for balance and grip.

A roof access hatch must also be able to be held open by an external device, so it cannot close on itself and cause injury. Hatches should also include a locking arm feature that allows for the cover or door to lock in an open position.

If left open, the hatch can pose a serious fall hazard. The use of guardrails around a roof access hatch has been made mandatory in both Canada and the US to avoid falls and injuries. OSHA requires the railing to include a self-closing gate or chain enclosure. Since this is often an overlooked requirement, even on new projects, we offer our HatchGuard protection system, which consists of a non-penetrating clamp-on hatch guardrail system, with hand-grips to aid in access and egress, and a self-closing safety gate.

Ontario building code requirements

Below are included some of the building code requirements that relate to roof access. It’s worth noting that the Ontario building code is constantly being updated, so it’s important to stay on top of the changing regulations.
Ontario building code – attic access
The Ontario building code regulations state that an attic space that is higher than 600 mm must have access from the floor immediately below by either a safe stairway or by a hatch no smaller than 550 mm by 900 mm.

Ontario building code – loft or attic stairs

The general building code regulations that apply to stairs are as follows:

  • The incline must be no greater than 45 degrees
  • Risers must be no greater than 210 mm high
  • Treads must be no greater than 220 mm wide (excluding nosing)
  • Headroom above the stairway cannot be less than 1950 mm (in dwelling units) or 2050 mm (not within dwelling units), plus the height of one riser. This measurement is taken vertically above a tread or a platform.

Handrail requirements for stairs are as follows:

  • Handrails must be installed on at least one side of stairways less than 1100 mm wide, and on both sides of a stairway wider than 1100 mm
  • Excepting dwelling units, handrails must be installed on both sides of a curving stairway regardless of width

Handrails are not required for interior stairways with no more than two risers.

Ontario building code – fire access route

Any building that is greater than three storeys high OR 600 square metres in building area must have access routes for fire department vehicles. This includes a principal entrance as well as access routes for firefighters.

Fire access routes must meet the following criteria:

  • They must have a width of at least six metres
  • They must have overhead clearance of at least five metres
  • They must have a climate-resistant surface like concrete or asphalt
  • They must be connected with a public thoroughfare

No part of an access route can be any further down than 20 metres below floor level of the uppermost storey of the building.

Every access opening must be located between three and 15 metres from the closest part of the route required for use by a fire department. This measurement must be taken horizontally from the face of the building.


Roof hatches are a convenient way for workers to access a rooftop, and can provide an important access point as an emergency exit or for emergency workers in the case of fire.

The appropriate implementation of fall protection regulations on rooftops can help keep a safe roof environment.

Additionally, failure to observe these regulations can result in some hefty fines. It’s important to install the right guardrail system to ensure that working on a roof or exiting from it remains safe – especially during long, icy winters and in emergency situations.

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