What to Do When You Discover Asbestos During Renovation

The Renovation Hazard Hiding in Plain Sight

Your renovation crew is removing old flooring when someone notices something unusual: the adhesive underneath has a chalky, fibrous texture. Or maybe a section of pipe insulation in the basement looks crumbly and gray. Or the popcorn ceiling that was supposed to be scraped clean turns out to have a different composition than expected.

In the Bay Area, where a large percentage of the housing stock was built during the mid-20th century, asbestos discoveries during renovation are common. This naturally occurring mineral was used extensively in building materials from the 1920s through the late 1970s because of its fire resistance, durability, and insulating properties. It was not until the late 1970s and early 1980s that the health risks became widely understood, and many of those original materials remain in homes today.

Discovering asbestos during a renovation is not a crisis, but it does require immediate, careful action. Here is exactly what to do.

Where Asbestos Hides in Bay Area Homes

If your home was built before 1980, asbestos may be present in any of the following materials:

Common Locations

• Popcorn ceilings and textured wall coatings. Widely used from the 1950s through the early 1980s. One of the most common asbestos discoveries during remodels.
• Vinyl floor tiles. The classic 9x9-inch floor tile is a strong indicator of asbestos content. The adhesive (mastic) used to attach these tiles also often contains asbestos.
• Pipe and duct insulation. White or gray insulation wrapped around heating pipes, water pipes, and HVAC ducts, especially in basements and crawl spaces.
• Cement siding and roofing. Asbestos-cement products were common for exterior siding, roofing shingles, and flue pipes.
• Joint compound and drywall tape. Used in wall and ceiling construction throughout the mid-century period.
• Insulation. Vermiculite attic insulation (particularly the Zonolite brand) and some blown-in wall insulation contain asbestos.
• Window putty and caulking. Older windows may have asbestos in the glazing compound.

Less Obvious Locations

• Behind wall tiles in bathrooms and kitchens (in the adhesive or backing)
• In electrical panel backing and wiring insulation
• In furnace and boiler gaskets and insulation
• In fireplace cement and surrounds

The important thing to understand is that you cannot identify asbestos by sight alone. Many materials that look identical can be either asbestos-containing or asbestos-free. Only laboratory testing can confirm the presence of asbestos.

Why Asbestos Is Dangerous

Asbestos fibers are microscopic and, when airborne, can be inhaled deep into the lungs. The body cannot break down or expel these fibers, and over time they cause scarring and inflammation. Long-term asbestos exposure is linked to:

• Asbestosis: A chronic lung condition causing shortness of breath and permanent scarring of lung tissue
• Mesothelioma: A rare and aggressive cancer of the lining of the lungs, abdomen, or heart, almost exclusively caused by asbestos exposure
• Lung cancer: The risk is elevated by asbestos exposure, particularly in combination with smoking

The key word is “exposure.” Asbestos materials that are intact and undisturbed generally pose minimal risk. The danger comes when the materials are cut, drilled, sanded, broken, or otherwise disturbed, releasing fibers into the air. This is precisely what happens during renovation and demolition work.

What to Do: Step by Step

Step 1: Stop All Work Immediately

If asbestos is suspected, stop all demolition, cutting, drilling, sanding, and sweeping in the affected area. Do not attempt to clean up any dust or debris. Do not use compressed air or shop vacuums, as these will spread fibers. Leave the area and close the door if possible.

Step 2: Do Not Disturb the Material

This is the single most important rule. Asbestos that is intact and undisturbed is not immediately dangerous. Asbestos that has been broken, crumbled, or pulverized releases fibers that can remain airborne for hours and settle throughout the home. If the material has already been disturbed during demolition, the area should be treated as contaminated until professional testing and cleanup are completed.

Step 3: Get Professional Testing

Contact a certified asbestos inspector to collect samples for laboratory analysis. In California, asbestos inspectors must be certified by the Division of Occupational Safety and Health (Cal/OSHA). The testing process involves:

• Careful collection of small material samples using wet methods to minimize fiber release
• Laboratory analysis using polarized light microscopy (PLM) or transmission electron microscopy (TEM)
• A written report identifying which materials contain asbestos and at what concentration

Standard testing costs $200-$800 depending on the number of samples. Results typically take 3-5 business days, with rush options available.

Step 4: Understand Your Options

If testing confirms asbestos, you have two primary options depending on the project scope:

Management in place: If the asbestos-containing material is in good condition and will not be disturbed by your renovation, it can be left alone or encapsulated (sealed with a protective coating). This is the least expensive option but limits future work in the area.

Professional abatement (removal): If the material will be disturbed by your renovation, it must be professionally removed before construction work can proceed. This is the most common path for remodeling projects.

Step 5: Hire a Licensed Abatement Contractor

In California, asbestos abatement must be performed by a contractor registered with Cal/OSHA and holding the appropriate C-22 (Asbestos Abatement) license. The abatement process includes:

1. BAAQMD notification. In the Bay Area, the Bay Area Air Quality Management District requires written notification at least 10 working days before any asbestos removal begins. This is a legal requirement with significant penalties for non-compliance.
2. Work area preparation. The area is sealed with plastic sheeting, and negative air pressure is established using HEPA-filtered equipment.
3. Wet removal. Materials are wetted to suppress fiber release and carefully removed by trained workers wearing full personal protective equipment.
4. Proper disposal. Asbestos waste is double-bagged in labeled containers and transported to an approved disposal facility.
5. Air monitoring. Before the area is cleared for re-entry, air samples are collected and analyzed to confirm fiber levels are below the permissible exposure limit.
6. Clearance documentation. A written clearance report is provided, confirming the area is safe for reoccupation and continued construction.

Step 6: Resume Your Renovation

Once clearance testing confirms the area is safe, your renovation can continue. The abatement process typically adds 1-3 weeks to the project timeline, depending on the scope of removal and BAAQMD notification requirements.

How Much Does Asbestos Abatement Cost?

Costs vary based on the type and quantity of material, accessibility, and location within the home.

Material Type	Typical Abatement Cost
Popcorn ceiling (single room)	$1,500 - $4,000
Popcorn ceiling (whole home, 1,500 sq ft)	$5,000 - $15,000
Vinyl floor tile and mastic (per room)	$1,500 - $3,500
Pipe insulation (per linear foot)	$15 - $65
HVAC duct insulation	$3,000 - $12,000
Whole-home abatement (multiple materials)	$15,000 - $30,000+

These costs are in addition to the testing fee and any permit fees required by your jurisdiction. For renovation projects, abatement costs are added to the overall project budget.

California Regulations You Need to Know

California has some of the strictest asbestos regulations in the country. Key requirements for Bay Area homeowners include:

• BAAQMD notification is required at least 10 working days before asbestos removal for most projects
• Cal/OSHA regulations require specific work practices, employee training, and monitoring for any asbestos-related work
• Licensed contractors only for any abatement work (C-22 Asbestos Abatement license)
• Proper disposal at licensed facilities with manifest documentation
• Penalties for non-compliance can include fines of $1,000 or more per day, project stop-work orders, and potential criminal charges for willful violations

How Experienced Builders Handle Asbestos

At Custom Home Design and Build, asbestos is part of our standard pre-construction assessment for any home built before 1980. Our approach:

• Testing before demolition. During Phase 1 of our design-build process, we conduct hazardous material testing on suspect materials before any demolition work begins. This identifies asbestos early and allows us to price abatement into the project budget upfront.
• Licensed abatement coordination. We work with trusted, licensed abatement contractors and handle all BAAQMD notifications and scheduling.
• Budget transparency. If abatement is needed, we provide clear cost information during the design phase, so there are no surprises when construction begins.
• Timeline integration. We build the abatement timeline into the project schedule, including the required BAAQMD notification period, to minimize overall delays.

Asbestos does not have to derail your renovation. With proper testing, professional abatement, and an experienced team, it is a manageable step in the renovation process.

Safety First, Always

Asbestos is a serious health hazard, but it is a well-understood one with clear, established procedures for safe handling. The most important thing you can do is stop work, get testing, and let licensed professionals handle the removal.

If you are planning a renovation on a Bay Area home built before 1980, proactive testing is always the smart move. It protects your health, your family, and your budget.

Contact Custom Home Design and Build to learn how our pre-construction assessment identifies asbestos and other hidden hazards before your renovation begins.