Radon action guide for municipalities: Building codes, bylaws and provisions

On this page

• Building codes
• Standards of maintenance bylaws
• Radon requirements in public spaces

Building codes

Varying building code provisions across Canada

There are radon provisions in the (model) National Building Code (with the radon provisions last updated in 2010). Many provinces have incorporated some radon provisions in their code.

To unpack the variety of codes in Canada it may be useful to analyze different radon reduction strategies, ranging from the most rudimentary to the most effective.

Soil gas barriers

This involves placing a membrane between the slab and the ground below. Soil gas barriers are not considered an effective stand-alone radon reduction strategy.

Radon rough-in with stub

This involves the sealing of radon (and other soil gas) entry points, granular material below the slab, and a radon rough-in 'stub'. This is a short vent pipe which rises from the floor and is capped. This was added to Canada's National Building Code in 2010 and has been adopted into several provincial and territorial building codes. There is a significant risk that high radon environments remain untested and unmitigated. Current best practices require more complete systems.

Passive sub-slab depressurization

This involves a pipe installed through the foundation that runs upwards through the inside of the building and vents to the outside at the roofline. British Columbia's building code started with the rough-in stub (following the National Building Code). A study found the radon rough-in stub was generally insufficient. This led to changes to the BC Code to require an outside venting pipe. While often effective at reducing radon, these systems cannot be relied on to reduce high radon concentrations to below the guideline level. Homes with these systems should still have the radon level tested.

Learn more about:

• Information bulletin: New Radon Rough-in Requirements (Government of British Columbia)
• A Comparison of Three Radon Systems in British Columbia Homes: Conclusions and Recommendations for the British Columbia Building Code

Active sub-slab depressurization

This involves adding a fan to passive sub-slab depressurization systems to further increase the reduction of radon. Québec's Construction Code now requires:

• the radon rough-in with stub
• radon test results to be submitted to the authority having jurisdiction (generally municipal building officials
• the addition of sub-slab depressurization sufficient to reduce levels to within Health Canada's Guidelines

Current best practices in mitigation are outlined in the Canadian General Standard Board's 2019 "Radon control options for new construction in low-rise residential buildings" and should be referenced in building codes. The standard provides detailed technical prescriptions for radon mitigation strategies.

There are significant benefits to targeting radon prone areas and requiring new homes to have operational systems (at least a passive sub-slab system), ensuring that homes are built with less radon in them and reducing the incidence of radon-induced lung cancer in higher risk regions.

If building codes continue to require forms of 'rough-ins' that are incomplete, provinces and territories should consider requiring clear labelling on these systems stating that they are incomplete, and that further radon testing is required by homeowners once they occupy the home. Provinces and territories can consider requiring builders to leave radon test kits and informational guides with new homeowners and requiring occupants of new homes to test for radon.

Learn more about:

• Residential radon (Government of Québec)
• Construction Code (Government of Québec)
• Radon control options for new construction in low-rise residential buildings (Canadian General Standard Board's 2019)

Radon in municipal building codes

In some provinces (Quebec, Newfoundland and Prince Edward Island), there are possibilities for municipalities to put more stringent requirements in place that go beyond provincial building code requirements.

• Building Codes Act, RSPEI 1988, c B-5.1 16(5); s. 26
• Municipalities Act, 1999, SNL 1999, c M-24414(1)(d), and s. 414(3)
• Act respecting land use planning and development, RSQ, c. A-19.1, 118

Some municipalities independently enact codes that meet the National Building Code (including for radon).

• City of St. Johns, Building By-Law, By-Law No. 1438, s. 46

Municipalities that have implemented their own radon standards include:

• Muncipalité de L' Ascension, Règlement numéro 2000-350 relatif à la construction s. 2.17.2
  • This calls for a rough-in stub similar to the National Building Code requirements.
• Muncipalité de Chelsea. Règlement de construction numéro 638-05 s. 9.5
  • These provide technical specifications for a 'rough in stub ' similar to the National Building Code provisions, plus requirements for testing and if over Canada's Radon Guideline, the connecting of a sub-slab depressurization system.

In Ontario, the radon provisions only apply in "known radon areas". The following municipalities have taken steps to implement the Building Code provisions and provide explicit direction to builders:

• Radon Gas Mitigation Program (Guelph, ON)
• Radon Gas Mitigation (Kingston, ON)
• Residential Construction Requirements for Radon Gas Mitigation (Hamilton, ON)

In British Columbia, the BC Building Code, 2018 lists specific municipalities where radon mitigation systems are needed (at Division B Appendix C Table C-4. Locations in British Columbia Requiring Radon Rough-Ins). Municipal governments can take steps to be added to this list if they have evidence of elevated radon in their area.

Building Code Enforcement

Municipal building inspectors are encouraged to make use of Canadian- National Radon Proficiency Program (C-NRPP) Training for Building Professionals: Controlling Radon in New Canadian Homes (CRNCH): CNRPP-EL-9.

Hamilton, Ontario's radon inspection process can serve as an important example. The web page clearly indicates builders' and owners' responsibilities. For new construction and/or additions, the property owner or builder is required to arrange for inspections relating to:

• sealing of the perimeter of the slab
• installation of soil gas barrier on foundation wall and under floor slab
• pipe cap and labelling and inline fan (where required) prior to occupancy
• installation of the rough-in soil gas pipe and granular material prior to pouring the basement slab

As well, depending on the radon gas mitigation option chosen by the builder, it is the property owner's responsibility to conduct radon gas testing (following specified procedures) and submit the results to the City. Where mandatory radon gas testing results come back above 200 Bq/m³, the property owner is to install an active subsoil depressurization system and ensure any resultant decrease in soil temperature will not adversely affect the foundation using documentation provided by a qualified person.

Standards of maintenance bylaws

Housing and maintenance standards

Many provinces have specific wording in municipal law allowing local governments to make standards of maintenance bylaws. For examples see:

• Local Government Act, RSBC 2015, c 1 298(1)(n)) (British Columbia)
• Municipal Act, CCSM c M225232(1)(c) and 233(a) (Manitoba)
• Building Code Act, S.O. 1992, c.23, 15.1 (Ontario)
• Act respecting land use planning and development, CQLR c A-19.1 145.41 (Quebec)
• Local Government Act, SNB 2017, c. 1810(1)(e) (New Brunswick)
• Municipal Government Act, RSPEI 1988, c M-12.1 180(i) (Prince Edward Island)

In some cases, there is a process for approval of standards of maintenance bylaws:

• Local Governance Act, SNB 2017, c 18 17(b) (New Brunswick)

Provinces also at times provide specific language directing municipalities to receive complaints, make investigations and issue orders against landlords.

• Residential Tenancies Act, 2006, SO 2006, c. 17224 to 225 (Ontario)
• Act respecting land use planning and development, CQLR c A-19.1 145.41 (Quebec)
• Occupancy and Maintenance Regulations, CNLR 1021/96, 41 (Newfoundland and Labrador)
• Residential Properties Maintenance and Occupancy Code Approval Regulation, NB Reg 84-86, s. 3 (New Brunswick)

Municipalities are encouraged to have standard of maintenance bylaws that protect renters indoor air quality, including from radon. Radon specific provisions can specify that:

• testing be repeated every 5 years
• tenants and prospective tenants must be notified by right of test results
• Canada's Radon Guideline applies to rental accommodation in the municipality
• landlords are required to test for radon following Health Canada approved procedures
• for average long-term results over 600 Bq/m³ mitigation must be completed within one year
• tenants have the right to conduct their own tests and a procedure established in case of disagreement
• for average long-term results over Canada's Radon Guideline mitigation must be performed by a C-NRPP certified radon professional to as low as reasonably achievable

Enforcement of bylaws

Municipalities should take steps to enforce standards of maintenance bylaws.

An example of an enforcement bylaw is the City of Waterloo's Rental Licensing Bylaw 2011-047. This has a number of provisions that could be used to enforce standards of maintenance:

• Allows city officials to enter on land to carry out inspections.
• Provides for the city to make orders to ensure compliance with the bylaw.
• Requires landlords to have a license to conduct a Residential Rental Business.
• If a landlord does not comply with an order, the city can make an order work and charge the landlord.
• Allows for a license to not be renewed to comply with the Building Code, or by the Medical Officer of Health:
  • in cases of non-compliance with the law, or
  • where there are outstanding orders pursuant to the City's Property Standards By-Law
• Allows the Director of Municipal Enforcement Services for the City (or his/her staff or designates) to require information and documentation as part of issuing or renewing a license, including that the landlord have a property maintenance plan to ensure compliance with the City's Property Standards bylaw.

Iowa City, Iowa has instituted Radon Testing Requirements for rental properties. This plans for a 2-year inspection cycle whereby all single family detached and duplex units that become rentals will need to be tested and come into compliance with the regulation.

Radon requirements in public spaces

Radon provisions for clean air and health bylaws

Municipalities can regulate radon in indoor spaces, including for businesses, recreation centres and other areas accessible to the general public. Similar to smoking regulations, these can be made a part of general health or clean air bylaws. Details can include:

• Testing be repeated every 5 years.
• Enforcement through business licensing and permitting.
• Test results should be clearly identifiable, posted, and visible to the public.
• For average long-term results over 600 Bq/m³ mitigation be completed within one year.
• The municipal government creates an inspection process to verify testing and mitigation has occurred.
• Indoor spaces open to the public should have radon levels below Canada's Radon Guideline of 200 Bq/m³.
• Business owners, governments and other occupiers of buildings are required to test for radon following Health Canada approved procedures.
• For average long-term results over Canada's Radon Guideline mitigation must be performed by a C-NRPP certified radon professional to as low as reasonably achievable.