Radon Connect
Learning centre

Mitigation systems

What actually gets installed in my house, and how do I know it works?

The gap between a good mitigation system and a bad one is almost entirely invisible after the drywall dust is swept up. Both look like a pipe. The difference is in the diagnostics that chose the suction point, and in whether anyone measured afterwards.

This hub follows the job in order: understand the mechanism, understand what your foundation forces the design to do, know what a competent installation day looks like, and verify. Verification is the step most often skipped, and it is the only one that produces evidence.

Who this is for. Someone deciding whether to mitigate, or about to have work done, or holding a system that is not performing.

The reading order

6 steps, 15 resources. Nothing below is written here — every link goes to the page that holds the substance, and the note under each one says what it adds at that point in the sequence. A hub that restated its own links would just be competing with them.

  1. Whether to mitigate at all

    This is a real decision with inputs, not an automatic consequence of a number above a threshold.

    • Should I mitigate? Tool

      Works through result validity, level, occupancy, and transaction pressure before it says anything about acting.

    • Testing versus mitigation Page

      Where the boundary between measuring and fixing sits, and why paying for the second without finishing the first is common and avoidable.

  2. How a system actually works

    Active soil depressurisation reverses a pressure difference. It does not filter indoor air, and knowing that rules out several products a homeowner gets offered.

  3. What your foundation forces the design to do

    Slab, crawl space, and mixed foundations lead to different systems. A quote that does not reflect yours has not been designed for your house.

  4. Installation day

    Knowing the sequence lets you tell a competent crew from a fast one while the work is still happening.

  5. Verify, then file the evidence

    A system with no post-installation measurement is an unverified claim. This is the step that turns work into proof.

  6. When it did not work

    A retest that comes back high is a diagnosable problem with an order of likely causes, not a reason to start over.

    • System not working Guide

      Symptoms mapped to causes, cheapest and most likely first.

    • Retest failed Guide

      What obligations a properly written contract already gave you in this exact situation.

What you should be able to do afterwards

  • Say what your foundation type implies about the design, before a contractor tells you.
  • Recognise, on the day, whether the diagnostic step happened.
  • Insist on a post-installation measurement as a deliverable rather than a favour.
  • Work a failed retest as a diagnosis instead of a dispute.

Related hubs

Confidence and limits of this page

Every decision resource on this platform states its own boundaries. This is not a disclaimer — it is the part of this hub you should read before relying on it.

What we knowClaims on this page we stand behind, each traceable to an approved source or to observable structure.
  • Active sub-slab depressurisation is the method published mitigation guidance describes for most slab and basement foundations, and it works on pressure rather than on filtration.
  • Foundation type materially changes both the design and the labour involved, which is why identical square footage produces different quotes.
  • A post-installation measurement is what establishes that a system reduced the level, and no visual inspection substitutes for it.
What we do not knowQuestions you may reasonably have that this page does not answer.
  • What any specific house will read after mitigation, which depends on soil, construction, and the diagnostics performed at the suction point.
  • How long a specific installation will hold its performance, since that depends on the building, the fan, and whether anyone watches the pressure gauge.
What research would settle itWhat it would actually take to answer the above — naming it is the difference between honesty and hedging.
  • Before-and-after pairs across foundation types with documented diagnostics, which would let anyone state expected reduction by design rather than in general terms.
  • Field follow-up several years after installation, which is the only way to describe how performance drifts rather than how it starts.
What we do not claimClaims you might expect to find here and will not, with the reason.
  • We do not claim a percentage reduction any system will achieve, because that figure depends on diagnostics we did not perform on a house we have not seen.
  • We do not claim any fan model, membrane product, or sealant performs better than another, because we hold no comparative field data and a ranking without it would be fabricated.
  • We do not rank or recommend individual mitigation companies anywhere on this platform.
What we cannot independently verifyFacts this page relies on that we could not confirm ourselves.
  • Whether a particular contractor performed diagnostics on your house, which only their documentation and your own observation can establish.
  • The current content of the cited guidance documents, for the network reason stated in our methodology.

Sources

  1. U.S. EPA — Consumer’s Guide to Radon Reduction
  2. U.S. EPA — Radon
  3. U.S. EPA — A Citizen’s Guide to Radon

Get quotes from credentialed local contractors

Free to request and no obligation. We verify credentials with the issuing authority before any request routes to a contractor.

Start a request