Post-remediation verification, usually shortened to PRV or clearance, is the independent check that the remediation achieved what the protocol required.
It is the reason the Texas licensing structure separates assessors from remediators, and it is the single most valuable document to come out of a mold job.
The sequence matters
Clearance happens at a specific point, and getting the order wrong is expensive.
- Removal and cleaning complete
- Structure dried to the documented standard
- Containment still in place, negative air still running
- Clearance performed
- Clearance passes
- Containment comes down
- Rebuild begins
The reason step four sits before step seven is simple. If clearance fails, the correction happens in an open cavity with the containment already built. If you have insulated, drywalled, textured and painted first, the same correction means undoing all of it.
Any contractor who suggests closing up before clearance is either cutting a corner or does not intend to have the work checked. It is worth pushing back on.
What the assessor checks
Visual inspection
First and most important. No visible growth remaining, no visible dust or debris on any surface within the containment, and materials specified for removal actually removed to the specified boundary.
The dust point is not cosmetic. Settled dust in a remediated area contains the spores released during demolition, and a job that removed the growth but left the debris has not finished.
Moisture verification
Readings across the affected framing and substrate, compared to unaffected reference areas of the same material in the same building. Wet material behind new drywall regrows, so this is checked before anything closes.
Air sampling
Spore trap samples inside the containment, in adjacent unaffected areas, and outdoors as the control. All taken the same day under comparable conditions.
The pass criteria: the containment air should look like the outdoor air in composition and be no higher in concentration, and the water-damage indicator genera — Stachybotrys, Chaetomium, Fusarium — should be absent.
Aggressive sampling
Some protocols specify agitating the air with a fan before sampling, so settled spores are put into suspension. It is a harder test and a more honest one, because it approximates what happens when the room is put back into normal use rather than sampling a room that has been sitting undisturbed.
What a failure means
A failed clearance is not a disaster and it is not unusual. It usually means one of four things.
Cleaning was incomplete. Settled dust remains on framing, on the containment sheeting itself, or in a corner that was hard to reach. The fix is another HEPA pass and re-testing.
The boundary was drawn too tight. Growth extends past where the cut was made. More material comes out.
A second source exists. The sampling finds an indicator genus that the identified source does not explain, which means there is something else in the building nobody has found yet. This is the most useful kind of failure, because finding it now is far better than finding it in a year.
Containment leaked. Adjacent-area samples come back elevated, meaning the negative pressure was not maintained and the rest of the house has been contaminated during the work. That is the expensive one, and it is the reason engineering controls are not optional.
In every case the remediator returns and corrects at their cost, then re-tests. That is what the arrangement is for.
The Texas certificate
When licensed remediation is performed on a project above the threshold, Texas provides for a Certificate of Mold Damage Remediation to be issued to the property owner.
It is worth more than most people realise at the time.
Texas requires sellers to disclose known mold damage on a residential property. Holding a certificate turns that disclosure from a liability into a resolved item: the damage existed, it was remediated by a licensed contractor, and it was independently verified. Without it, a buyer has only your description of what happened.
It also matters to insurers, and in some circumstances an insurer may not deny coverage or increase premiums on a property solely because of mold damage that has been properly remediated and certified. Keep the certificate with the property documents, not in a drawer.
Who pays for it
A question worth settling before work starts.
Clearance is normally engaged by the property owner directly with the assessor, precisely so the remediator is not the assessor's client. Where a remediation contract includes clearance in its price, ask who selects the assessor and who receives the report. The answers tell you how independent it really is.
Where an insurance claim is involved, the carrier frequently requires clearance before releasing the reconstruction payment, which means it is happening regardless.
Related: mold inspection for the assessment that produces the protocol in the first place, and mold damage repair for what happens once clearance passes.
Common questions
Is clearance testing required by law?
On licensed projects in Texas the protocol governs, and protocols specify clearance criteria. Where a certificate is to be issued, verification is part of the process.
Can the remediation company do their own clearance?
On licensed work the independence requirement exists for exactly this reason. Even where it is technically permitted, an independent assessor is what makes the result worth anything.
How long does it take to get results?
Visual and moisture verification are same-day. Laboratory air results usually take two to five business days, and containment stays up until they come back.
What happens if it fails?
The remediator corrects the deficiency at their cost and it is re-tested. Failures are usually incomplete cleaning or a boundary drawn too tight, and both are straightforward to put right while the wall is still open.
Do I need clearance on a small job?
Not legally, below the threshold. It is still worth doing if there was a health concern driving the work, or if you may sell the property in the next few years.
How long should I keep the certificate?
Permanently, with the property records. It is the document that answers the disclosure question when you sell.
Get a free assessment
Tell us what you are seeing and where. We come out, find the moisture source, and put the scope and the price in writing before anything is torn out.