Radon Mitigation Contractor Contracts: What Should Be Included

When you hire a radon mitigation contractor, the document you sign does more than set a price. It defines the work, the performance targets, the risks both sides accept, and what happens when surprises pop up inside your walls or under your slab. A clear, complete contract saves money and avoids bad blood. I have reviewed hundreds of radon proposals over the years, from small bungalows in south city to multistory homes in West County and older stone basements near the river bluffs. The best contracts read like a roadmap. You know what will be built, how it will look, the standards it will meet, and how success will be measured.

This guide breaks down what a homeowner should expect to see in a solid radon agreement, with context for the St Louis area. Whether you typed “Radon mitigation near me” and found a local shop, or you are working with a regional name that does a lot of St Louis radon projects, the same principles apply. Great contractors put this in writing because it protects both sides.

Start with the standard: performance and code language

A legitimate radon mitigation system is not just a fan and a pipe. It is a pressure management setup built to specific standards. Your contract should reference the current ANSI/AARST standards that apply to your home type. For most houses, that is SGM-SF for existing homes with soil gas mitigation. If a crawlspace is part of the footprint, the contractor may also reference standards for crawlspace depressurization or membrane installation. These standards define diagnostic steps, acceptable materials, sealing requirements, labeling, alarms, and discharge locations.

Local codes matter too. In the St Louis region, municipal building departments often require permits for a radon system, particularly if there is electrical work. The contract should state who pulls permits, who pays permit fees, and which edition of electric and building codes apply. In homes with garages, firestopping at rated walls may be required where the pipe passes through. If a roof penetration is planned, the contract should explicitly address roof flashing and how the roofer’s warranty will be protected.

A well written scope will also include compliance with electrical safety. Expect to see a reference to GFCI or AFCI requirements where appropriate, a dedicated or shared circuit plan for the radon fan if it is in an attic, and UL listings for components. In a few Stl radon jobs I have reviewed, the lack of a GFCI outlet near an exterior fan caused a failed electrical inspection. That is the sort of headache a good contract prevents.

Scope of work that leaves no guesswork

The scope is the heartbeat of the agreement. It should read like a short project plan. Be specific enough that anyone could show up with the contract and build the same radon system.

Key elements that belong in the scope:

The mitigation method. For a slab or basement, this is usually sub slab depressurization with one or more suction points. For a crawlspace, it is sub membrane depressurization with a sealed liner. If a hybrid system is necessary, say slab plus crawlspace, the contract should say so. The pipe route from the suction point to the discharge. List whether the route is interior through the basement and garage attic, or exterior on the outside wall. Describe penetrations, such as through the rim joist or roof, and whether the contractor will paint exterior PVC to match the house. The fan location and model class. The exact make and model can be named or at least a performance class should be specified, for example a mid range fan with approximately 150 cfm at 1 inch water column. The fan should be outside the living space, commonly in the attic or outdoors. If mounted outdoors, the contract should mention a weather rated housing or painted fan shell. Sealing and prep. Outline crack sealing in slabs, sealing of the sump lid with a gasketed cover and pass throughs, caulking around slab penetrations, and blocking of major bypasses that can short circuit suction. Condensate handling. Radon fans pull moist air from soil. The contract should describe a condensation bypass or drain where appropriate, as well as insulation for vent pipe in unconditioned attics to prevent winter condensation. Discharge termination. This includes height above roof, distance from windows or soffit vents, and avoidance of dormers that recirculate air. If an exterior system terminates on a side wall, the contract should be very clear that this is not allowed by ANSI/AARST standards. The discharge needs to go above the roofline at a safe distance from openings.

Detail protects you. I once saw a low bid for a St louis radon job that described “one suction, one fan, one pipe” and nothing more. The fan landed in a basement mechanical room, which violated the standard by placing the motorized component inside the conditioned space. Fixing it after the fact required an attic reroute and new wiring. That second bill cost more than the difference between the original bids.

Diagnostics and design decisions before drilling

Good contractors do diagnostics. Your agreement should commit them to a basic set of tests before they choose a suction point. Common diagnostics include a communication test using a shop vacuum or temporary suction to see how air moves under the slab, smoke tests to find air leaks, and pressure field extension measurements. If the house has multiple slab sections, a sunken living room, or a thick stone foundation from an older era, diagnostics decide whether you need one suction point or two.

Design also depends on the measured sub slab pressure and the aggregate beneath the slab. In parts of St Louis County built in the 1970s and 1980s, I often find tight soil under the slab. That tends to require a more powerful fan or additional suction points. In newer builds with clean gravel beds, a smaller fan often does the job. A contract that summarizes the diagnostic approach sets the expectation that design is based on data, not guesswork.

Materials and craftsmanship standards

If a proposal just says “PVC pipe,” ask for more detail. The contract should list the pipe size, typically 3 inch or 4 inch Schedule 40 PVC, and state that all fittings and solvent cement are compatible. Flexible couplings above the fan help with service and vibration. Labeling is required by standard, so the contract should promise system labels on visible runs and a label with the install date and contractor info near the fan.

Sealing the sump is more than putting a lid on it. Specify a transparent or removable cover that allows service, with grommets for pump lines and the radon suction connection. Crawlspace membranes should be at least 6 mil polyethylene, often reinforced, sealed at seams and edges with compatible tape and mastic. In older stone basements common in St louis radon work, the transition from rough stone to membrane needs careful detailing. A line in the contract about “continuous air barrier at perimeter” tells me the crew knows how to handle it.

Noise and aesthetics belong in the scope too. If the exterior route runs along a visible elevation, the agreement can include paint to match the siding, or a shield that breaks up the pipe line. Interior runs should avoid bedrooms when practical. Vibration isolators and thoughtful strapping reduce hum. If your house is on a zero lot line, the discharge placement needs extra care so it does not blast your neighbor’s open window in summer.

Electrical work and alarms

Radon fans are permanently wired or plugged into a dedicated outlet. The contract should state who provides the outlet and wiring. If the contractor includes electrical work, it should reference a licensed electrician or include license numbers where required by the city or county. If you must provide an outlet before the install, the contract should say that clearly and tie it to the schedule.

Every radon system needs a monitoring device, at minimum a U tube manometer or digital pressure gauge mounted on the vent pipe to show the fan is running. Many companies now offer audible flow alarms or Wi Fi monitors. If monitoring is included, the contract should list the device, whether a subscription is required, and who maintains it. I like to see a simple statement guaranteeing the system will include a visible indicator of operation that the homeowner can check.

Pricing structure, allowances, and change orders

Flat bids are fine if the house is simple and the path is clear. For complicated houses, an allowance structure can protect both sides. For instance, if the design assumes one suction point yet diagnostics show you need a second, the contract can list a fixed price for each additional suction point. If core drilling through a 10 inch foundation wall is required, an allowance can cover the specialized labor and bit wear. Good contracts do not hide these scenarios. They call them out.

Change orders should be in writing, with price and schedule impacts. An email confirmation is often enough, but the base contract should require written approval before extra work proceeds. Clarity here avoids the classic scene where a crew chief says “we had to add this” and hands you a bigger bill at the end.

For payment terms, many radon mitigation contractor agreements use a deposit at scheduling, then final payment after installation and post mitigation testing. Make sure the trigger for final payment is clear. If payment is due upon passing a post test, the contract should state the target concentration and the testing method.

Performance guarantee and post mitigation testing

Radon is invisible, so success is measured by test results. Your contract should commit the contractor to a specific post mitigation test window and method. Many firms place a short term test kit after a 24 hour fan run in winter or during closed house conditions. Others bring a continuous radon monitor and can generate a report within 48 hours. Either approach is fine if the method meets EPA or state protocols.

What matters most is the performance target. The industry standard is to reduce levels to below 4.0 pCi/L. Many reputable companies in Radon mitigation St Louis also aim to reduce levels below 2.0 pCi/L when feasible. A nuanced contract will say the system is designed to achieve as low as reasonably achievable, with a guarantee that if the post test remains above 4.0 pCi/L, the contractor will return to add suction points, seal additional cracks, or upgrade the fan at no cost within a defined scope. I prefer to see a defined window, often 12 months, that covers seasonal swings. In clay heavy soils, radon can creep up in a wet spring. A follow up visit under warranty shows the company stands behind their radon system.

If you already have a long term monitor, such as a digital unit on your shelf, note that in the contract and ask the contractor to use that data to verify performance in addition to their one time post test. When both readings agree, everyone sleeps better.

Warranties that actually help you

There are two warranties to look for. First, the manufacturer warranty on the radon fan, usually five years for a quality unit. Second, the installer’s workmanship warranty. In my experience, a three to five year workmanship warranty is reasonable. It should cover pipe joints, seals, sump covers, and membrane seams. If a sump lid gasket fails and leaks air, a good warranty will send a tech to reseal it.

Read the exclusions. The warranty often excludes damage from abuse, roof leaks unrelated to the vent flashing, or unrelated foundation movement. In older basements with visible efflorescence or active water, a contractor may exclude damage caused by bulk water. That is fair, but the contract should still commit to using water resistant materials, such as stainless screws outdoors and exterior rated sealants.

Ask for transferability if you might sell the home. A transferable warranty is a selling point. Many St Louis buyers now ask for radon test results during inspection, and a solid warranty on the installed system can smooth that conversation.

Homeowner responsibilities, access, and safety

Contractors cannot do their work if the mechanical room is piled with boxes or the sump is blocked by a freezer. The contract should list what you must do before the crew arrives. Clearing a path, unlocking gates, corralling pets, and moving a shelf from the planned suction point are small but essential tasks. If hazardous materials like asbestos insulation or lead paint are present in the work area, the contract needs a plan. Often this is a pause clause, where the contractor stops work and notifies you if a suspect material is discovered. Remediation or testing becomes a change order handled by specialists.

Utility locates are another item. For exterior trenching or drilling near a driveway, the contractor should commit to calling in locates. Inside the house, the contract should require the contractor to scan for rebar, hydronic tubing, or radiant heat lines before coring the slab. I have seen a coring crew flood a mechanical room by drilling through an old copper line embedded in the slab. A one sentence scan requirement in the contract can prevent that mess.

Site protection belongs here too. Include dust control methods, such as using HEPA vacuums when drilling, and a cleanup standard at the end of each day. Some municipalities require OSHA compliant silica dust collection when cutting concrete. A contract that mentions dust control shows a company that takes health and inspections seriously.

Schedule, weather, and access to the roof

Most residential systems take one day to install, occasionally two if multiple suction points or crawlspace membranes are involved. The contract should list the expected duration and the start date window. If roof work is planned, weather can delay the job. In St Louis winters, icy roofs can push an exterior discharge to a safer day. The contract should give the contractor the right to reschedule for safety, and it should promise prompt communication if weather shifts the plan.

If your home belongs to an HOA, the agreement should note that you are responsible for HOA approvals for exterior pipes or fans. Some HOAs allow attic routes that hide most of the system. That design can cost more, so the contract should price the attic route separately if you are still seeking HOA approval.

Insurance, licensing, and certification

Mitigation companies should carry general liability insurance and workers’ compensation. The contract should list coverage with policy numbers or at least promise a certificate upon request. If an electrician is involved, the electrical license holder should be identified. Most towns in the metro area accept NRPP or NRSB certification for radon professionals. Ask for the certification numbers in the contract. This matters when you sell the house, because buyers and inspectors sometimes ask who did the work and whether they were certified.

Documentation you should receive at the end

A polished finish is not just silicone beads and tidy straps. It is paperwork that proves what was built. Your contract should list the closeout documents you will receive:

A system diagram or as built photo set that shows the suction point, pipe route, and fan location. The fan make and model, with serial number and warranty registration. The pre and post mitigation test reports, with the testing method and dates. Maintenance tips, such as how to read the manometer and when to call for service. Any permits, inspection sign offs, and a copy of the invoice marked paid.

Years from now, when a home inspector peers at the pipe and asks about the system, that packet will be gold.

Pricing red flags and fair ranges

Every market is different, and pricing moves with labor, materials, and fuel. In the St Louis area, a straightforward sub slab depressurization system often lands between 1,200 and 2,000 dollars, depending on pipe route and finish details. Crawlspace encapsulation with a membrane can add 800 to 2,000 dollars or more, based on size and access. If you are quoted half that for a full system, read the scope twice. If you are quoted triple that with light detail, ask what justifies the premium.

Big spread on bids often comes from route choices and fan class. An exterior pipe is generally cheaper than an attic route. A high suction fan can mask poor sealing or weak diagnostics. The contract should explain why a certain fan class is chosen. I keep a note from a job in Clayton where a mid range fan kept the house under 1.5 pCi/L most of the year. In a humid summer, levels crept above 3.0. The contractor had built an access tee near the suction point and wrote in the contract that they could add a second suction at a fixed price if needed. That design decision and contract language saved everyone time when the second suction was added three months later.

Dispute resolution and right to cancel

Reputable companies rarely end up in disputes, yet the contract should still have a simple resolution path. Many use mediation or small claims court depending on the amount. Arbitration clauses appear in some boilerplate forms. Read them. If you are uncomfortable with forced arbitration, ask to amend that clause. In Missouri, consumers often have a three day right to cancel for door to door or off premises sales. If your contract was signed at your kitchen table, that right may apply. The agreement should include a clear notice of your cancellation rights where applicable by law.

A brief checklist you can use while reading a bid

Performance target stated, with ANSI/AARST compliance and code references. Clear scope of work that names pipe route, fan location and class, and discharge details. Diagnostics described, including how many suction points are assumed and what triggers more. Electrical plan, permits, and who pays fees. Post mitigation testing method and timing, with a written performance guarantee.

Print that list and place it next to any proposal. If a contractor’s document hits all five, you are in better hands.

Who handles testing and the grey zone between measurement and mitigation

Some companies only install systems. Others also sell testing. It is acceptable for a mitigation company to perform the post test that verifies their work. It is also fine to hire an independent tester if you want a third party measurement. What matters is the chain of custody and a method consistent with EPA protocols. If you are considering Radon mitigation St Louis companies that also do real estate testing, you can ask for a separation of roles. A clean contract will specify that the mitigation crew will not alter post test devices or close dates, and that any testing is performed under closed house conditions for the required period.

Remember that radon is driven by pressure differences and soil conditions that change with weather. If your first post test shows 2.8 pCi/L in a wet spring, and a second test in late fall shows 1.1 pCi/L, that variation is normal. A solid performance guarantee accounts for seasonal drift, not a single snapshot.

Maintenance and long term ownership

A radon system is low maintenance, but not no maintenance. The contract should include a brief maintenance note. Expect fan lifespans of 5 to 10 years. The manometer should show a pressure difference when the fan runs. If the fluid level is equal on both sides, the fan is off or a tube has come loose. If the system includes a filter on a crawlspace membrane connection, plan to check it annually. Ask if the contract includes a one year checkup or if those are available for a set fee.

In real estate transactions, a buyer’s inspector will often ask for a post mitigation test within a specified time. Keep your documentation handy. A contractor who installed your system should be able to respond quickly with a test, especially if your contract states priority service for original clients. I have seen sales hinge on that responsiveness, and a one day turnaround on testing can keep a closing on track.

Local context for St Louis homes

The St Louis housing stock brings quirks. Tuck under garages, split level slabs, and old limestone foundations appear across the metro. In some south city blocks, basements have thin slabs over cinders. Communication testing becomes critical because air can short circuit through voids. In Webster Groves and Kirkwood, crawlspaces are common under additions. The contract should not pretend these are one size fits all. If your house straddles a slab and a crawl, your scope radon mitigation services near me should too.

Exterior temperature swings also play a role. Winter stack effect pulls more soil gas into homes, which is when radon levels often spike. A good contract will recommend doing the post test during a period that represents your higher risk season if practical. That might mean a test in January or February rather than an August week with windows open. If you cannot wait, the performance guarantee should bridge the gap.

Finally, some municipalities have their own inspection steps. Ask the contractor to list the jurisdictions they work in, for example St Louis City, St Louis County, St Charles, or specific smaller cities. Permitting and inspection schedules vary. A contract that promises permit pulling and inspection coordination in your specific town shows the company knows the local ropes.

Questions to ask before you sign

Which ANSI/AARST standard will you follow, and how will you document compliance for my records? Where will the radon fan be located, and what are the pros and cons of that placement for noise, service, and energy? What diagnostics will you do before drilling, and how will those tests affect the final design? If my post mitigation test does not meet the target, what are the exact steps and costs, if any, to reach the goal? Who performs electrical work and pulls permits, and when will inspections be scheduled?

Keep the answers with your contract. Clear answers now prevent surprises later.

Pulling it all together

A radon mitigation system is a permanent safety upgrade, and the contract should reflect that level of care. The document you sign should set performance expectations, lay out a design informed by diagnostics, and define the materials and methods to be used. It should address permits, electrical work, testing, warranties, and the realities of your particular house. If you are evaluating Radon mitigation St Louis providers, ask them to show you a sample agreement. Measure it against the points above. The right radon mitigation contractor will not hesitate to put the details in writing, because a precise contract produces a better installation and a measurable result.

If you already have bids in hand, read them line by line and mark any gaps. A short addendum can patch a good bid into a great agreement. When the system is on, the manometer shows a healthy pressure, and your post test comes back under the target, you will be glad you took the extra hour to get the paperwork right.

Air Sense Environmental – Radon Mitigation & Testing

Business Name: Air Sense Environmental – Radon Mitigation & Testing
Address: 5237 Old Alton Edwardsville Rd, Edwardsville, IL 62025, United States
Phone: (618) 556-4774
Website: https://www.airsenseenvironmental.com/

Hours:
Monday: 9:00 AM – 5:00 PM
Tuesday: 9:00 AM – 5:00 PM
Wednesday: 9:00 AM – 5:00 PM
Thursday: 9:00 AM – 5:00 PM
Friday: 9:00 AM – 5:00 PM
Saturday: Closed
Sunday: Closed

Plus Code: RXMJ+98 Edwardsville, Illinois
Google Maps URL: https://maps.app.goo.gl/XTPhHjJpogDFN9va8

Google Maps Embed:

"@context": "https://schema.org", "@type": "HomeAndConstructionBusiness", "name": "Air Sense Environmental - Radon Mitigation & Testing", "url": "https://www.airsenseenvironmental.com/", "telephone": "+16185564774", "address": "@type": "PostalAddress", "streetAddress": "5237 Old Alton Edwardsville Rd", "addressLocality": "Edwardsville", "addressRegion": "IL", "postalCode": "62025", "addressCountry": "US" , "openingHoursSpecification": [ "@type": "OpeningHoursSpecification", "dayOfWeek": ["Monday"], "opens": "09:00", "closes": "17:00" , "@type": "OpeningHoursSpecification", "dayOfWeek": ["Tuesday"], "opens": "09:00", "closes": "17:00" , "@type": "OpeningHoursSpecification", "dayOfWeek": ["Wednesday"], "opens": "09:00", "closes": "17:00" , "@type": "OpeningHoursSpecification", "dayOfWeek": ["Thursday"], "opens": "09:00", "closes": "17:00" , "@type": "OpeningHoursSpecification", "dayOfWeek": ["Friday"], "opens": "09:00", "closes": "17:00" ], "geo": "@type": "GeoCoordinates", "latitude": "[Not listed – please confirm]", "longitude": "[Not listed – please confirm]" , "hasMap": "https://maps.app.goo.gl/XTPhHjJpogDFN9va8", "identifier": "[Not listed – please confirm]"

1) Semantic Triples

https://www.airsenseenvironmental.com/

Air Sense Environmental – Radon Mitigation & Testing is a professional indoor air quality specialist serving Edwardsville, IL and the surrounding Metro East region.

Air Sense Environmental provides quality-driven radon testing, radon mitigation system installation, and crawl space encapsulation services tailored to protect residential indoor environments.

Homeowners throughout Edwardsville, IL rely on Air Sense Environmental for local radon reduction systems designed to safely lower elevated radon levels.

To schedule radon testing or mitigation service, call (618) 556-4774 or visit https://www.airsenseenvironmental.com/ to speak with a quality-driven local specialist.

View the business location and directions on Google Maps: https://maps.app.goo.gl/XTPhHjJpogDFN9va8 and contact Air Sense Environmental for highly rated indoor air solutions.

What services does Air Sense Environmental provide?

Air Sense Environmental provides professional radon testing, radon mitigation system installation, indoor air quality solutions, and crawl space encapsulation services in Edwardsville, Illinois and surrounding areas.

Why is radon testing important in Illinois homes?

Radon is an odorless and invisible radioactive gas that can accumulate indoors. Testing is the only way to determine radon levels and protect your household from long-term exposure risks.

How long does a professional radon test take?

Professional radon testing typically runs for a minimum of 48 hours using continuous monitoring equipment to ensure accurate results.

What is a radon mitigation system?

A radon mitigation system is a professionally installed ventilation system that reduces indoor radon levels by safely venting the gas outside the home.

How do I contact Air Sense Environmental?

You can call (618) 556-4774, visit https://www.airsenseenvironmental.com/, or view directions at https://maps.app.goo.gl/XTPhHjJpogDFN9va8 to schedule service.

Landmarks Near Edwardsville, IL

Southern Illinois University Edwardsville (SIUE)
A major public university campus that serves as a cultural and educational hub for the Edwardsville community.

The Wildey Theatre
A historic downtown venue hosting concerts, films, and live entertainment throughout the year.

Watershed Nature Center
A scenic preserve offering walking trails, environmental education, and family-friendly outdoor experiences.

Edwardsville City Park
A popular local park featuring walking paths, sports facilities, and community events.

Madison County Transit Trails
An extensive regional trail system ideal for biking and walking across the Metro East area.

If you live near these Edwardsville landmarks and need professional radon testing or mitigation, contact Air Sense Environmental at (618) 556-4774 or visit https://www.airsenseenvironmental.com/.

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Pub: 07 Mar 2026 11:36 UTC

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