Radon Mitigation
Licensed Radon Mitigation in Fort Collins and Northern Colorado
Radon cannot be seen, smelled, or tasted, but it can accumulate in any type or age of home. Colorado public-health officials report that approximately half of Colorado homes test at or above the EPA action level of 4.0 pCi/L. The only way to know the level in a specific building is to test it.
Drennen Custom Contracting provides radon measurement and mitigation for existing homes, real estate transactions, crawl spaces, passive-system activations, new construction, multifamily properties, schools, and commercial buildings throughout Northern Colorado. Our radon work is performed by Colorado-licensed professionals or by trained personnel working under the supervision required by Colorado law.
Colorado-Licensed Radon Professionals | In-House Testing Program | Existing Homes and New Construction | Serving Northern Colorado Since 1973
Colorado has required individual radon measurement and mitigation professionals to hold a state license since July 1, 2022, unless a specific statutory exemption applies. Before hiring anyone, verify the responsible professional in the Colorado DORA license lookup.
What Radon Mitigation Does
Most residential radon systems use active soil depressurization. A continuously operating fan creates negative pressure beneath the slab or beneath a sealed crawl-space membrane. Soil gas is collected before it enters the occupied area and is exhausted safely outdoors above the roofline or at another compliant discharge location.
Sub-Slab Depressurization
Suction points are created beneath a basement slab or slab-on-grade foundation. The design depends on the soil, slab divisions, foundation walls, additions, and how well air can move beneath the concrete.
Sub-Membrane Depressurization
A durable gas-retarder membrane is installed over crawl-space soil and sealed at walls, piers, penetrations, and seams. Suction is applied beneath the membrane rather than simply ventilating the crawl space.
Mixed-Foundation Systems
Homes with basements, slabs, crawl spaces, additions, or multiple foundation elevations may require more than one suction point, separate collection zones, or a carefully balanced system.
Passive-System Activation
Newer homes may already have a passive radon stack. A licensed professional must inspect the existing components before adding a fan because an incomplete or poorly routed passive system may need correction first.
What a Complete Drennen Installation Commonly Includes
Foundation evaluation and system design
We evaluate the lowest occupied or occupiable areas, foundation types, existing passive components, crawl-space conditions, mechanical equipment, routing, electrical access, and potential discharge locations.
Soil-gas collection
Depending on the building, the system may use a sub-slab suction point, perforated collection piping, a crawl-space collection network, an existing passive rough-in, or a combination of methods.
Radon-rated piping and fan
The vent system is designed for soil gas and matched to the pressure and airflow conditions found at the property. Fan selection is not based on house size alone.
Sealing and conditioned-air control
Accessible foundation openings, crawl-space membrane details, sumps, and penetrations are addressed as part of the system. Sealing supports depressurization but is not a reliable stand-alone radon solution.
Monitoring and labeling
A system should include the required monitoring device or alarm, a pressure indicator where applicable, and clear system identification so the owner can tell whether the system is operating.
Post-mitigation testing
Drennen includes post-mitigation testing after installation so the result is documented. Homeowners should continue to retest at least every two years and after significant changes to the building or system.
Why Colorado Licensing Matters
Radon work is specialized environmental work, not ordinary plumbing. Colorado law regulates both measurement and mitigation. The license types are separate: a Radon Measurement Professional is licensed to conduct professional testing, while a Radon Mitigation Professional is licensed to design, install, repair, and modify mitigation systems.
A company name, general contractor license, plumbing license, home-inspector credential, or national certification by itself is not a substitute for an active Colorado radon license. Assistants may perform work only within the structure allowed by Colorado law and under the required supervision of the licensed professional.
Drennen Radon Services
Radon Testing
Professional testing for homeowners, real estate transactions, post-mitigation verification, multifamily properties, schools, and large buildings.
Radon Mitigation Cost
Real 2026 planning ranges for passive-system activation, straightforward slab systems, crawl spaces, mixed foundations, repairs, and complex projects.
Crawl-Space Mitigation
Membrane design, sealing, suction, moisture considerations, access, and long-term serviceability.
New Construction
Coordination before the slab pour, passive and active system design, rough-in standards, membrane details, routing, inspections, activation, and testing.
Real Estate Support
Licensed testing, fast scheduling, mitigation estimates, transaction documentation, post-installation results, and communication with buyers, sellers, and brokers.
Repair and Maintenance
Fan replacement, system inspection, alarm and manometer issues, condensation, loose piping, crawl-space membrane repairs, and performance troubleshooting.
What Makes Drennen Different
Drennen is both a long-established general contractor and a specialized radon company. That combination is valuable when a mitigation route intersects roofing, siding, crawl-space construction, drainage, electrical coordination, framing, or new-construction sequencing. Our roofing and radon divisions are separate specialties that can coordinate when a project crosses both trades.
Drennen operates an in-house radon testing program and laboratory workflow under its licensed measurement department. Our mitigation department designs systems for ordinary homes as well as difficult mixed foundations, new construction, multifamily buildings, and large facilities.
Our Process
- 1
Start with a valid radon result
We review the result, test type, test location, timing, transaction deadline, and whether the building already has a passive or active system.
- 2
Evaluate the building
We identify foundation zones, crawl spaces, slab divisions, route options, fan locations, electrical needs, and conditions that may affect pressure-field extension.
- 3
Provide a written scope
The proposal should identify the system approach, included components, assumptions, optional work, warranty terms, and post-installation testing.
- 4
Install and verify
The system is installed under the licensed mitigation program, checked for operating pressure and field extension as appropriate, labeled, documented, and tested after completion.
Frequently Asked Questions
Get a Licensed Radon Evaluation
Whether you have a high test result, an inspection deadline, a crawl-space problem, an old fan, or a new building still on the plans, Drennen can help identify the correct next step and explain the scope in plain language.
This page provides general educational information, not medical, legal, engineering, or code advice. Laws, adopted standards, local permit requirements, and license status can change. Verify current requirements with DORA, CDPHE, and the authority having jurisdiction.
Drennen Custom Contracting | Serving Fort Collins and Northern Colorado | 970-482-9100 | [email protected]