Radon is a hidden hazard in Nova Scotia, with 36.8% of homes exceeding Health Canada's safety guideline of 200 Bq/m³ - more than double the national average. This radioactive gas poses serious health risks, including lung cancer, especially in multi-unit rental properties. For developers, addressing radon during construction is cost-effective and avoids expensive retrofits later.
Here’s what you need to know:
- Radon rough-ins: A system added during construction to make future mitigation easier. It includes a gas-permeable layer, venting pipes, and foundation sealing.
- Testing is essential: Rough-ins alone don’t guarantee safety. Long-term testing is needed to confirm radon levels meet safety standards.
- Mitigation options: Passive systems reduce radon by 30–70%, while active systems with fans achieve 50–99% reduction.
- Legal and health stakes: Ignoring radon risks can lead to costly retrofits, legal issues, and tenant health risks.
Adding radon systems during construction protects tenants, reduces long-term costs, and increases property appeal in Nova Scotia’s rental market.
Radon Risks and Requirements in Nova Scotia
Radon Levels and Health Effects
Nova Scotia faces one of the most pressing radon challenges in Canada. Around 36.8% of homes in the province exceed Health Canada's guideline of 200 Bq/m³, which is more than twice the national average of 17.8% [1]. This alarming statistic is particularly important for anyone planning to build multi-unit properties in the region.
Radon is a naturally occurring gas that forms when uranium in soil and rock breaks down [1]. It enters buildings through cracks and gaps in foundation walls and floors, driven by pressure differences between indoor and outdoor environments [1]. Once inside, radon can accumulate to dangerous levels, even though it’s completely odourless and invisible.
The health risks are serious. Health Canada estimates radon exposure causes over 3,000 lung cancer deaths annually across the country [1]. In Nova Scotia alone, radon is linked to more than 100 deaths each year [1]. Prolonged exposure to high radon levels significantly raises the risk of lung cancer, and for smokers, that risk is even greater.
In multi-unit rental properties, the stakes are even higher. A single building with elevated radon levels could expose dozens of tenants to this health hazard over time. Nova Scotia's Radon Risk Map highlights areas categorized as high, medium, or low risk, reflecting the province's varying potential for radon release based on local geology [1].
These serious health concerns have led to strict building code standards aimed at mitigating radon risks.
Building Code Requirements for Radon Systems
Nova Scotia follows the radon provisions outlined in the National Building Code, which property owners need to understand and comply with.
The code requires all new constructions to include radon rough-ins. This involves installing a gas-permeable layer beneath the foundation slab and a vent pipe that runs from below the slab to above the roofline. While this vent is passive by default, it can be upgraded with an active fan system if post-construction testing shows high radon levels.
It’s important to note that rough-ins alone don’t guarantee safe radon levels. They simply make it easier to install an active mitigation system later if needed. The building code does not require radon testing or the activation of mitigation systems during construction, leaving these steps up to the property owner.
Health Canada uses a guideline of 200 Bq/m³ as the threshold for when additional mitigation is recommended [1]. However, this is a health-based guideline, not a legal limit, meaning property owners should take action if radon levels exceed this benchmark.
Ultimately, the building code's rough-in requirements represent just the starting point. For property owners who prioritize tenant safety, thorough testing and proactive mitigation are essential steps to go beyond the minimum standard.
Radon Rough-Ins: First Step in New Construction
What Is a Radon Rough-In?
A radon rough-in is a system built into a home’s foundation during construction to make future radon mitigation easier, if it's ever needed. Essentially, it sets up the groundwork for addressing radon without requiring major changes to the foundation later.
Here’s what a typical radon rough-in involves:
- Gas-permeable layer: A layer of clean gravel under the concrete slab that allows radon gas to move freely beneath the foundation.
- Venting system: PVC piping installed from beneath the slab, running up through the building and exiting above the roofline to safely vent radon outdoors.
- Sealing: Cracks, joints, and other openings in the foundation are sealed to limit radon entry.
These components are added before the concrete is poured, avoiding the expense and hassle of retrofitting after the home is built. While this system creates a passive radon mitigation setup, which uses natural air pressure to vent radon, it may not always be enough if radon levels are high.
Why Rough-Ins Alone Are Not Enough
While a radon rough-in is a great starting point - and often required by building codes - it’s not always a complete solution. If radon levels remain high, additional steps may be necessary.
In some cases, contractors install rough-ins just to meet code requirements, leaving the responsibility of further mitigation to the homeowner. This makes post-construction radon testing critical. Testing should be done over a period long enough to account for seasonal changes in radon levels, ensuring accurate results.
If testing shows elevated radon levels, the passive system can be upgraded by adding an active fan to improve ventilation. For multi-unit buildings, where radon levels can vary significantly between units or floors, individual testing is essential to ensure the entire property is protected.
Incorporating these measures during construction helps create a radon-ready property, offering peace of mind for future occupants while minimizing long-term costs. It’s a proactive step towards safer living spaces.
Radon mitigation in new construction
Radon System Options for Multi-Unit Properties
Once radon rough-ins are in place, property owners need to decide on the best system to ensure long-term radon mitigation for their multi-unit properties. Several options are available, each with its own level of effectiveness, cost, and maintenance needs.
Passive Sub-Slab Systems
Passive sub-slab systems rely on natural pressure differences to vent radon gas without the need for an electric fan [2]. These systems create a pathway for radon to escape through pipes installed during construction, safely venting it above the roofline.
The key advantage of passive systems is that they operate silently and don’t require electricity [2]. However, their performance has notable limitations. They typically reduce radon levels by 30% to 70% [3], which may not be enough for properties with higher radon concentrations.
The main issue with these systems is their reliance on the "stack effect" - the natural movement of air caused by temperature and pressure differences. In modern, airtight multi-unit buildings, this natural airflow is often too weak to significantly reduce radon levels [3]. As a result, passive systems alone are often insufficient in regions like Nova Scotia.
Active Sub-Slab Systems
Active sub-slab systems build on the passive design by incorporating an electric fan to actively draw radon out of the building [2]. This simple addition greatly improves the system's effectiveness, making it a top choice for multi-unit properties that require consistent radon control.
Active systems are far more effective, reducing radon levels by 50% to 99% [3]. The fan provides continuous suction beneath the foundation, ensuring reliable radon removal regardless of weather or air pressure changes.
These systems use quiet, energy-efficient fans and come with a five-year warranty [2]. Importantly, active systems can handle any radon level, making them ideal for buildings where concentrations vary between units or floors. This ensures comprehensive protection for all tenants.
| System Type | Effectiveness | Operation | Best For |
|---|---|---|---|
| Passive | 30-70% reduction | Silent, no electricity | Low radon areas |
| Active | 50-99% reduction | Quiet fan, low energy use | All radon levels |
Additional Radon Reduction Methods
In addition to sub-slab systems, there are other measures that can enhance radon mitigation in multi-unit properties. These methods work best as supplements rather than standalone solutions.
- Foundation sealing: Sealing cracks, joints, and other openings helps limit radon entry points. While useful, this method alone cannot stop radon from infiltrating the building without a sub-slab system.
- Improved ventilation: Increasing air circulation throughout the building can dilute radon levels. This includes maintaining HVAC systems, ensuring exhaust fans work properly, and encouraging natural air exchange. However, ventilation alone rarely achieves the reductions needed to meet safety standards.
- Crawl space ventilation: For properties with crawl spaces, adding vents or fans can prevent radon from accumulating in these areas before it enters living spaces.
These additional measures are most effective when combined with an active sub-slab system. Together, they create a multi-layered approach to radon mitigation, offering tenants greater peace of mind and safety.
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Radon Testing Plan: Meeting Safety Standards
Installing radon rough-ins and mitigation systems is a critical step, but it’s just the beginning. To ensure these systems are working as intended, testing is necessary to confirm they meet safety standards.
Testing Timeline and Methods
Health Canada recommends conducting long-term radon testing during the heating season[5]. For new homes, this means scheduling the test during the first heating season after the property is occupied. In Nova Scotia, this typically spans from October to April, when windows are kept closed, and the thermal stack effect can lead to higher indoor radon levels[5].
To get an accurate picture of annual radon exposure, tests should last between three and 12 months[4][5]. Short-term tests, which take less than a month, are not reliable as they fail to account for daily and seasonal fluctuations in radon levels.
Adding Radon Systems to Construction Plans
Incorporating radon mitigation into your construction plans from the start improves safety, keeps costs under control, and avoids future headaches. By including radon systems in the initial designs, you can streamline the construction process and make better use of your budget.
Cost and Budget Planning
Adding radon systems during the construction phase is typically much cheaper than retrofitting them later. For example, installing passive radon systems while working on the foundation avoids the need for expensive and disruptive retrofits down the road. In larger projects, such as multi-unit buildings, these savings can multiply across all units.
It’s wise to plan for the possibility of upgrading to an active radon system if post-construction testing shows it’s necessary. This forward-thinking approach helps you address potential radon issues without the stress or expense of unexpected retrofitting.
Additionally, properties with radon mitigation systems in place can stand out in Nova Scotia’s rental market. Documented measures not only provide peace of mind to tenants but can also give your property a competitive advantage.
Working with Builders and Contractors
Not all builders are experienced in radon mitigation, and this lack of expertise can lead to mistakes or oversights. When no single contractor is responsible for coordinating the project, radon system installation can fall through the cracks. To avoid these issues, it’s essential to hire builders who treat radon mitigation as a standard part of their building process.
Ask potential builders about their experience with radon systems and request references from past radon-ready projects. A skilled builder will ensure that all trades - foundation workers, plumbers, electricians, and others - are properly coordinated, reducing the chance of errors during installation.
An integrated construction team can make a big difference. When everyone works together, radon rough-ins are more likely to be installed correctly on the first attempt. Builders with local knowledge of soil and geological conditions are especially valuable, as they can recommend the most effective radon mitigation system for your site.
To protect yourself from unexpected costs, include radon rough-ins in fixed-price contracts. Also, make sure your builder provides a clear plan for post-construction radon testing, along with a timeline for any necessary follow-up actions. This thorough approach ensures a safer, more efficient property while keeping everything on track from start to finish.
Conclusion: Building Healthier, Safer Rental Properties
Creating radon-ready rental properties in Nova Scotia isn’t just about meeting building codes - it’s about fostering healthier living spaces that safeguard both your tenants and your investment. By adding radon rough-ins during construction and implementing a solid testing plan, you’re taking meaningful steps to protect everyone involved.
Incorporate radon rough-ins during the foundation phase, conduct post-construction testing, and only upgrade if necessary. This approach helps keep upfront costs manageable and avoids the need for costly retrofits down the line.
It’s also crucial to work with builders who have experience in radon mitigation. Contractors familiar with these systems can streamline the process, reducing the headaches often caused by miscommunication between trades. Integrated construction teams ensure that radon mitigation systems are installed correctly from the start, saving time and resources.
The benefits extend beyond health and safety. Nova Scotia’s rental market increasingly values properties with proven safety measures. Tenants are drawn to landlords who prioritize their well-being, and radon-ready properties often attract reliable tenants willing to pay premium rents and stay for the long term.
On a broader scale, every radon-ready property contributes to healthier communities across the province. By setting a higher standard for tenant safety, you’re encouraging other property owners to follow suit, creating a ripple effect that benefits the entire housing sector.
Starting your next multi-unit project with radon mitigation in mind isn’t just a smart financial move - it’s a commitment to quality and safety. A small investment in radon rough-ins and testing today can save you from significant expenses later, all while building a reputation for excellence that supports your business for years to come.
FAQs
Why should radon levels be tested in a home with radon rough-ins installed during construction?
Radon rough-ins are a helpful starting point, but they don’t ensure that radon levels in your home are within safe limits. Radon levels can differ greatly, even between homes right next to each other, because of variations in soil composition and construction methods. The only way to know for sure if your home meets Health Canada’s recommended radon safety levels is through proper testing.
Testing for radon not only helps protect the health of everyone in your household but also gives you peace of mind. If elevated radon levels are found, it allows you to take timely steps to address the problem.
Is it more cost-effective to include radon mitigation systems during construction or to add them later?
Including radon mitigation systems during the construction phase is a smart financial move. Installing these systems during the build is simpler, using fewer materials and requiring less labour. On the other hand, retrofitting later can be much pricier, as it often involves altering existing structures and dealing with potential disruptions to tenants or building operations.
Thinking ahead allows property owners to create safer spaces, comply with health standards, and sidestep the higher costs of retrofitting. Plus, it ensures the long-term well-being of future tenants.
How can property owners confirm their builder has experience with radon mitigation in new homes?
When evaluating a builder's experience with radon mitigation, it's important to ask whether they have undergone training in radon-resistant construction methods. Also, confirm that they actively apply these techniques during the building process. Make sure their practices align with the National Building Code of Canada and any relevant provincial regulations concerning radon safety.
You should also choose a builder who can clearly outline their approach to radon mitigation. This includes explaining the materials they use, how they integrate rough-in systems, and their plan for post-construction radon testing. A detailed plan ensures the home meets safety standards and keeps radon levels in check.
