Guide

How Long Does Radon Mitigation Take?

The full sequence

Stage	Duration	What is actually happening
Initial short-term test	2 to 7 days, plus lab time on some kits	Closed-house conditions, device undisturbed
Confirmation test, if needed	2 to 7 days short-term, or up to 365 days long-term	DEP recommends confirming a 4 to 8 pCi/L result
Site visit and quote	Under an hour on site	Foundation assessment, diagnostics, scope
Scheduling	Days to a couple of weeks	Contractor availability, permit if required
Installation	Usually 1 day	Core, pit, pipe, fan, seal, manometer
System stabilisation	At least 24 hours	The house reaching its new steady state
Post-mitigation test	2 to 7 days	The number that is the actual deliverable

Add it up and a normal, unhurried path is about two to three weeks. Note how little of that is labour. The constraint is test periods, and those are fixed by physics rather than by scheduling.

What the install day actually looks like

1. Diagnostics and final suction point selection, including communication testing if it was not done at the quote
2. Core a hole through the slab, typically four to five inches, and excavate a pit beneath it
3. Run and support the pipe, interior through the house or exterior up a wall, to above the roofline
4. Mount the fan outside the living space and wire it with an accessible disconnect
5. Fit the manometer somewhere you can actually see it
6. Seal accessible slab openings, the sump lid and the perimeter joint
7. Label the system as the standards require, and walk you through it

It is dusty work at the coring stage and there will be a period of drilling noise. Most households carry on normally around it.

What extends it

• Multiple suction points, where diagnostics show one will not depressurise the whole slab
• A crawlspace membrane, which is slow, awkward work in a confined space
• Mixed foundations, basement plus crawlspace, which are separate soil-gas environments and often need separate systems
• A finished basement, where routing and restoration take longer
• Permits, where the borough or township requires one
• A post-test that comes back above the action level, which means adjustment and a retest
• Winter, where exterior work and frozen ground slow things down

The real estate version

On a transaction the sequence compresses, and the compression comes from a specific decision: skip long-term confirmation testing and act on a short-term result.

1. Days 1 to 3: buyer's inspection radon test comes back elevated
2. Days 3 to 5: contractor site visit and quote, negotiation over who pays
3. Days 5 to 10: installation scheduled and completed
4. Day 11: system has run 24 hours, post-test starts
5. Days 13 to 17: post-test result in hand

About two weeks, and it works if it starts immediately. The failure mode is always the same: the parties spend ten days negotiating who pays, and then discover there is no longer room in the schedule. See radon and home sales.

What you can do to keep it short

1. Test early, before you list, so the result is not a surprise on someone else's clock
2. Clear access to the intended suction point area and the pipe route before install day
3. Agree in writing what happens if the post-test does not come in below 4 pCi/L
4. Ask up front whether a permit is needed and who is pulling it
5. Do not switch the fan off between install and post-test. The test measures what the system is doing
6. Keep closed-house conditions during the post-test, or the number will not be valid

That last one gets missed surprisingly often, and it wastes a full week when it does. See radon testing and our process.

Common questions

Is the install really one day?

For a standard sub-slab system in a single-family home, usually yes. Crawlspace membranes, multiple suction points and mixed foundations can push it to two days. The rest of the timeline is testing, not labour.

How soon can I test after installation?

The system needs to run at least 24 hours before a post-mitigation test starts, so the house reaches its new steady state. Then the test itself runs 2 to 7 days depending on the device.

Can this be done before my closing date?

Usually, if you start as soon as the inspection result lands. Roughly two weeks covers a confirmation test, a site visit, the install and a post-test. Leaving it until the final week is where deals get extended.