Who this page is for
- Schools and childcare facilities, where the occupants are children spending long hours in ground-floor rooms
- Apartment buildings, condos, and other multifamily property, where every ground-contact unit is its own exposure question and the owner carries the liability
- Offices, medical and dental practices, and workplaces with occupied ground-floor or below-grade space
- Churches, community buildings, and nonprofits with finished basements in regular use
- Buyers and lenders in commercial real estate transactions, where radon has become a standard environmental due-diligence line item
Why building size changes the problem
A single-family house is one pressure envelope over one foundation. A commercial building usually is not.
The footprint is larger, and soil is not uniform underneath it. One corner of a building can read very differently from another. This is why a large building gets a grid of measurements rather than a sample.
Mechanical ventilation dominates the pressure relationships. A residential radon system fights the modest stack effect of a house. A commercial building has air handlers, make-up air, and exhaust systems that can put whole zones under negative pressure relative to the soil, actively drawing soil gas in. Sometimes the most effective first move is an HVAC balancing change rather than a mitigation system.
Occupancy constrains everything. You cannot vacate a school for a week or shut down a leasing office. Work gets phased, scheduled after hours, and sequenced so occupied space stays usable.
The deliverable is documentation. For a house, the outcome is a lower number. For a commercial building, the outcome is a lower number plus a report that a school board, a lender, an insurer, a licensing agency, or a buyer’s environmental consultant will read and rely on.
Testing protocols
Measurement placement. Every ground-contact occupied room, which in a school means classrooms rather than a sample of the hallway, and in multifamily means every ground-contact unit. Frequently occupied below-grade spaces are included regardless of their nominal use.
Method. Continuous radon monitors are the practical default for commercial work. Hourly data lets you see the influence of HVAC cycling and weather, and it produces a defensible record. Charcoal detectors have a role in high-count deployments where cost per point matters.
Conditions. Testing is performed under normal building operating conditions, with HVAC running as it does day to day. A test conducted with the air handlers off does not describe the building anyone actually occupies.
Timing. Winter, if the schedule allows, for the same closed-building reasons that make winter the conservative season in residential testing.
Follow-up. Any room over the action level gets a confirmation measurement before mitigation is designed, because mitigation designed off a single anomalous reading is expensive to get wrong.
Mitigation design for larger buildings
The underlying method is still active soil depressurization. What changes is that it becomes an engineering exercise rather than a standard install.
Design typically starts with diagnostics: pressure field extension testing at candidate locations to find out how far suction actually travels under this specific slab, given this specific sub-slab material. That measurement determines how many suction points the building needs and where they go, and no honest fixed price exists before it.
From there: multiple suction points manifolded into properly sized fans, often with more than one fan system across a large footprint; HVAC integration, since pressure relationships have to be accounted for and sometimes adjusted; routing that respects the building’s structure, finishes, and occupancy; and monitoring, because on a commercial system it is worth having something better than a manometer somebody has to remember to look at.
Then post-mitigation testing across the same measurement grid, which is the document that closes the project.
What you get in writing
For a commercial client the paperwork is a real part of the deliverable:
- Full measurement report: device placement, serials and calibration, start and stop times, building operating conditions, and results per location
- System design documentation, including diagnostic findings and the basis for the suction point layout
- Post-mitigation verification across the measurement grid
- As-built documentation of what was installed and where
- A monitoring and maintenance schedule, since fans on commercial systems age the same way residential fans do
That package is what satisfies a board, a lender’s environmental review, an insurer, or a licensing agency, and it is what a future buyer’s consultant will ask for.
Get a scoped quote
Commercial radon work is not priced from a table, and any number quoted before someone understands the building is a number that will change. What we need to scope it:
- Building type and use, and approximate square footage of ground-contact space
- Number of ground-contact rooms or units
- Foundation construction: slab, basement, crawl space, or a mix
- HVAC configuration, in whatever detail you have
- Whether you have prior radon results
- What is driving the request: due diligence, a licensing requirement, a board decision, or a tenant concern
- Your timeline and any access constraints
Use the form on this page rather than the phone. Commercial requests need details that are easier to write than to say, and a written scope gets you a more accurate number faster.
Frequently asked questions
Are schools and daycares in Indiana required to test for radon?
Requirements vary by facility type, licensing body, and funding source, and they change, so the only responsible answer is that you should confirm your specific obligation with the agency that licenses you rather than with a contractor's website.
What is not in dispute is the exposure case. Children spend long, predictable hours in the same ground-floor rooms, Delaware County is EPA Zone 1, and EPA recommends radon testing in all schools and childcare facilities regardless of what any given regulation requires. If you are asking whether you have to, the more useful question is usually what it costs to know.
How do you test an apartment building for radon?
Not by testing one unit. The standard approach for multifamily is to test all ground-contact units, meaning every unit with a floor over soil, slab, basement, or crawl space, plus ground-contact common areas such as laundry rooms, offices, and storage.
Upper-floor units generally carry lower risk, but they are not automatically exempt: stairwells, elevator shafts, and utility chases can move soil gas upward. Sampling design should be decided per building, and results vary widely between units in the same structure, which is exactly why a single sample cannot represent the property.
How is commercial radon mitigation different from residential?
Scale changes the engineering. A large slab needs a designed suction field with multiple points and a fan system sized to it, not a single fan on a single pipe. The building's HVAC is now a major variable, because pressure relationships created by mechanical ventilation can either help or actively work against a mitigation system, and in some buildings HVAC adjustment is part of the solution.
Occupancy adds constraints residential work does not have: phased scheduling, after-hours work, keeping tenants or students in place, and coordinating with a facilities team. And the paperwork requirement is real, because the results are going to a board, a lender, an insurer, or a licensing agency.