Short answer
Containment is a sealed plastic barrier around the work area; negative air pressure is a HEPA-filtered air scrubber that pulls air out of that space so it always flows in rather than out. Together they keep spores from spreading into clean parts of the building during removal.
Without them, demolition of colonized drywall distributes spores through the whole property and into the HVAC returns. Cross-contamination is the reason a bedroom job sometimes becomes a whole-house job.
Every removal we perform is done inside containment with negative air, HEPA vacuuming and controlled disposal, regardless of job size.
Why it matters in San Diego
San Diego homes are often open-plan, with central air and attic returns. Disturbing mold without containment pushes spores straight into ducts and the rest of the house. We've been called into homes in Escondido and Chula Vista after another company skipped containment — and the cleanup cost more than the original job.
How we handle it
We seal the work area with plastic sheeting and a zipper door, cover vents, and run a HEPA air scrubber that pulls air out of the room and vents it outside. Air flows into the work area, never out of it.
We check pressure throughout the job. Containment is in every quote we write — it's not an upsell.
Signs it's time to call us
- A contractor says containment 'isn't needed' for a wall or ceiling job
- No HEPA air scrubber on site
- Vents left open during removal
Mistakes to avoid
- Choosing a quote that skips containment to save money
- Running central air during removal
- Leaving doors open between rooms
Related questions
Does containment take long to build?
Usually an hour or two at the start of the job.
Is negative air loud?
It's a steady fan noise, similar to a window air conditioner.