Why this floor shows up so often
From roughly the 1920s into the 1980s, resilient floor tile was cheap, durable and easy to lay over concrete. Many Denver-area basements finished in the post-war building boom received it, often in nine-inch squares, and a dark asphalt-type adhesive held it to the slab. Some of those tiles and some of those adhesives were made with asbestos. Others were not. Nobody can tell the difference by color, size or age alone.
The tile itself is generally considered non-friable when it is intact, meaning it does not crumble in the hand. That changes once it is broken, sanded, pulverized or soaked and pried loose. The adhesive is a separate material with its own sample result, and it can test positive when the tile above it does not, or the other way around.
Basements also tend to be where water damage happens. A failed water heater, a backed-up floor drain or a burst supply line sends water under the tile, the squares lift, and the instinct is to rip them out so the slab can dry. That is the moment this guide is written for.
Tile, mastic and what usually happens to each
| Material | Typical condition | Common way it gets disturbed | What to ask the inspector |
|---|---|---|---|
| Nine-inch resilient tile | Hard, brittle with age, may be curling at seams | Prying up after a leak, breaking during demolition | Sample the tile layer separately from the adhesive |
| Twelve-inch resilient tile | Often later, but not automatically asbestos-free | Same as above, or overlaid with new flooring | Do not assume the larger size rules it out |
| Black or dark adhesive | Sticky or hard, sometimes visible at broken edges | Grinding, scraping, solvent stripping | Sample adhesive at more than one spot |
| Layers under a newer floor | Hidden under carpet, laminate or vinyl plank | Removal of the newer floor during remodeling | Ask whether lower layers will be sampled too |
If water has already reached the floor
- Stop the water and stay safe.Shut off the supply, and keep away from standing water near outlets or appliances. If gas appliances are affected or you smell gas, leave and call the gas utility or 911.
- Remove water without breaking tiles.Extraction of standing water can usually proceed. Ask the water mitigation provider to avoid lifting, cracking or scraping the tile until results are in.
- Arrange sampling quickly.Contact a CDPHE-certified asbestos building inspector and explain that drying is waiting on results. Ask how soon the lab can turn samples around.
- Keep the area closed.Limit foot traffic over loose or broken squares and avoid running fans that blow across broken edges.
- Plan removal from the results.If tile or mastic is positive, removal belongs to a CDPHE-certified abatement contractor. If both are negative, normal flooring removal can go ahead.
Questions to ask before anyone lifts the floor
Ask these of the inspector, the mitigation provider and any abatement contractor you are considering.
- Will you sample the tile and the adhesive as separate materials?
- How many sample locations make sense for a floor this size?
- Can drying equipment run without disturbing the tile while results are pending?
- What is your current CDPHE certification, and may I check it with CDPHE?
- If the mastic is positive and the tile is not, how does that change the removal scope?
- Will clearance be evaluated by someone independent of the removal contractor?
Common questions
Can I just tile or carpet over the old floor?
Covering intact tile is sometimes chosen to avoid disturbing it, but it leaves the material in place for a future owner or remodel. Record what is there, ideally with lab results, so whoever opens the floor later knows what they are dealing with.
Is the tile dangerous to walk on?
Intact tile under normal foot traffic is generally considered low risk. The concern is breaking, sanding or pulverizing it.
General information for the Denver area, not a quote or professional advice. In an emergency, call 911.