LIKE A 'RAINFOREST'

MOULD LEFT by marijuana grow houses is "really scary stuff" and has to
be removed with great care, specialists say. And while a proper
environmental assessment and mould remediation job can be costly,
dealing with it improperly can quickly turn a home into an
environmental disaster.

"You are dealing with a saturation of humidity through the entire
house for long periods of time," said Frank Haverkate, of Haverkate &
Assoc. Inc. indoor environmental testing and consulting.

Haverkate, who has now tested 20 or so grow houses, says the extreme
"rainforest-like" environment of a grow house typically creates mould
in and behind drywall, on floor joists, in carpets and furniture and
roofs.

If mould is found, Haverkate said, it must be treated with respect and
should not be disturbed without containing the area to avoid the
release of mould spores.

"Some construction companies have no idea what they are doing,"
Haverkate said. "Any monkey can put up drywall and remove the surface
mould, but to do it properly takes expertise."

Haverkate has linked up with Mississauga-based engineer and mould
inspector Darren Cooper, of Mould Scene Investigations (MSI) and Clean
Lab Evaluation and Remediation (CLEAR).

Cooper cites as an example a high-end Markham house that was used as a
grow-op for two years.

He said an insurance company and adjusters who had little insight into
mould approved a basement cleanup. They did not believe the mould had
spread to the second floor.

An inexperienced construction company failed to contain the mould, or
seal the forced air heating vents. Airborne mould spores spread
through the entire house.

Upon further inspection of the house two weeks ago, Cooper found
masses of mould behind the upper bedroom walls.

Now all drywall, wood panelling, furniture, carpets, insulation and
other porous objects have to be removed.

Wood floor and ceiling joists have to be blast-cleaned with dry ice
and the entire roof must be removed.

The entire project will top $180,000.

Cooper said mould cleanup must see the creation of negative pressure
in the house so mould spores do not blow around.

Mould has to be isolated, the heat vents sealed, and the removal and
clean up must be done with specialized equipment.

Workers must wear contamination suits, gloves and boots at all times
and use special breathing gear, he said.

Dr. James Scott, professor of environmental microbiology at the public
health sciences department of the University of Toronto, agreed that
grow houses are biologically "a mess."

Scott said a significant amount of mould on wallboard and other
materials "can mean very costly renovations."

"It is not just as simple as a using a claw hammer and throwing it
into a dumpster," Scott said.