Vermiculite insulation: asbestos risk and removal

What it looks like

Vermiculite is a loose-fill insulation poured between the ceiling joists. It is made of small, lightweight granules, a little like gravel or coarse cat litter, in grey-brown, silver or gold with a slight glitter. It does not come in batts or rolls and it is not fluffy like cellulose or fibreglass.

You may find it on its own or underneath newer insulation that was added on top later.

Why it matters

Vermiculite itself is a harmless mineral. The concern is where it came from. Vermiculite mined at Libby, Montana, and sold mainly under the brand name Zonolite from the 1920s until 1990, has been found to contain asbestos. The product was widely used in Canadian homes, particularly in the 1950s, 60s and 70s.

Not all vermiculite contains asbestos, but it is reasonable to assume that older vermiculite insulation may. You cannot tell by looking.

Is it dangerous to live with?

Health Canada’s advice has been that vermiculite which is sealed in the attic and left undisturbed poses little risk. The hazard comes when it is disturbed and fibres become airborne.

That means:

• Do not store things in the attic
• Do not let children play there
• Do not move it, sweep it or vacuum it
• Seal gaps in the ceiling, such as around light fixtures and the attic hatch, so that dust cannot fall into the rooms below
• Tell any trades who need to go into the attic

Vermiculite can also sift down inside wall cavities, so be cautious when opening walls in a house that has it.

Testing

A laboratory can analyse samples for asbestos. Because the asbestos is not evenly spread through the product, several samples from different areas and depths are usually taken, and a negative result on one sample is not conclusive. Sampling disturbs the material, so it should be done by someone trained to do it.

When it should be removed

• Before any renovation that opens ceilings or walls
• Before adding or replacing attic insulation
• Before electrical or other work in the attic
• Before demolition
• If it is falling into living space

How removal is done

Loose vermiculite throughout an attic is friable material over a large area, so in Ontario it is normally carried out under the highest level of precautions in Regulation 278/05:

1. The Ministry of Labour is notified before work begins
2. The house below is protected, the attic is isolated and the heating system is shut down and sealed
3. A decontamination area is set up for workers
4. The work area is kept under negative air pressure with HEPA filtration
5. The material is removed with specialised HEPA vacuum equipment and sealed in labelled containers
6. All surfaces are HEPA-vacuumed and wiped
7. Clearance air testing is done before the enclosure comes down
8. Waste goes to a facility permitted to accept asbestos waste

The attic then needs new insulation, which is a separate job.

If you are buying or selling

Vermiculite is a common finding in home inspections of older houses and can affect a sale and insurance. Disclose it, and get a written quote for removal so that the cost is known.

While you are deciding what to do

• Keep the attic hatch closed and weatherstripped
• Do not run wiring, install pot lights or do any work through the ceiling
• If the insulation has been disturbed, keep people out of the rooms below until it has been assessed
• Tell your home insurer if they ask about insulation type
• Do not top it up with new insulation, which makes later removal harder and more expensive
• Keep the test results and any removal paperwork with your house records, because future buyers and contractors will ask for them

More: asbestos removal and abatement.