Common Signs of Marijuana Grow-ops

Common Signs of Marijuana Grow-ops

Over the past few years I have had the privilege of learning about legal and illegal marijuana grow-ops. According to the RCMP (the foremost authority on the subject) thousands of illegal marijuana grow operations exist in the lower mainland & throughout BC. Knowing the signs of a grow-op is an important part of our job as we work to protect the interests of the public.

When residential homes are used as grow-ops, they are subjected to significant structural and mold damage. More disturbing, many grow ops have people living inside, which is very unsafe. Electrical safety issues, combined with barred windows can turn these properties into firetraps. The excess moisture created from these activities often promotes the growth of toxic mold, which can result in significant health concerns for the people living inside.

Once a home has been labeled as a grow op, it can be very difficult to sell, which is why some home owners will try their best to cover up the damage. Sometimes the signs are obvious, but sophisticated and clever techniques can make diagnosing a past grow op more challenging.

Below, I have listed a number of clues to look for, which will hopefully give you some additional knowledge before purchasing such a property.

  • A strong moldy odour inside the homeGrow ops rely on significant amounts of water and heat to create the ideal growth opportunity. Along with that comes the excessive humidity that can migrate into the walls of the building. Overtime, moisture, heat and drywall (food source for mold) create the perfect environment for mold to flourish. The more mold growth, the more problematic for the building and inhabitants.
  • Circular stains on the floors from potted plantsIn many grow ops, the floors are filled with pot plants. The excess water and chemicals used to grow these plants leave circular stains on the floors. Often these stains are on basement floors, but not always. Also, prior to selling, homeowners may install carpets over the floors to hide the staining. This clue may not be apparent until you renovate.
  • Strange, unusually altered or disconnected ductworkGrow operators have been know to reconfigure the existing heat ducts to accommodate the venting requirements needed for a grow op. Sometimes this arrangement is accompanied by the use of the carbon monoxide given off from furnaces and water heaters. In this case, their flues have been disconnected to provide the nourishment for the plants to thrive. This condition is especially dangerous to anyone either entering or living in the home.
  • Random, holes or repairs in the floors, walls, ceilings & the Foundation wallThis damage is created to provide the necessary venting and electrical runs that all grow ops need to work. Voids can be felt under carpet floors and patches seen along the walls and ceilings. At times, serious structural issues can arise when load bearing beams, floors and foundations have been compromised.
  • Evidence of security cameras installed on the exteriorThey are typically located in the front and back of the home along the corners, on the second level for the best coverage. Many times the cameras have been removed, but the mounting holes have been left behind. These cameras offer operators some peace of mind from rivals or the police, but would be overkill for the average homeowner, which makes it an obvious sign.
  • Strange modifications to electrical panels and/or sub panels installed randomly throughout the homeThis would certainly be a most probable sign pointing to the presence of a past grow-op. As mentioned, significant dangers can arise from these electrical configurations as well as the possibility of “creative” wiring behind finished areas, which is often accompanied by exposed junction boxes. All of these concerns can lead to electrical fires.
  • Significant mold growth in the attic, or dark stains seen from the soffits belowIf it doesn’t seem feasible to vent the exhaust through the roof or out the exterior wall, some operators will try and vent out through the soffit or into the attic. Soffit venting is common, (and in my opinion not recommended) even for a non grow-op home. When excess humidity is being pushed out through the soffit, visible staining will become apparent. Inside the attic the sheathing will quite likely be covered in dark fungal staining and mold growth. The longer the operation, the more damage to the roof decking.
  • Fortified doors with brackets and a 2×4, or several windows with barsAnother form of protection apart from the security cameras would be is the fortification of exterior doors and windows. I usually see them in the basement. This too would certainly cause me to raise my eyebrows and ask a few questions. Here again is an example of a firetrap.
  • Melted snow on the roof, compared to snow covered roofs on nearby homesAfter a snowfall, properly insulated roofs will be covered with snow. The upper attic will be cold and the floor will be warm. However, grow-ops produce a lot of warm, humid air that rises into the attic. This warm air causes the rooftop snow to melt.
  • Significant condensation along the windowsThis is caused by the excessive indoor humidity, resulting from the high heat, moisture and inadequate venting. This interior moisture contributes to the overall moisture damage & mold growth inside the home.

Depending on the type of conditions found, and areas affected, costs for rehabilitation can vary dramatically. In some extreme cases the entire home will have to be demolished.

Noticing a few of these signs does not mean that the home was in fact a grow-op. But the more signs you see in one home, the more likely it is to be.

If you suspect that a home for sale may have been a grow-op, ask to find out why certain modifications have been done. See if the owners have permits for the renovations, especially if they involve electrical or structural changes. Ask if you can have permission to call the city about the home to discover more. Essentially, you want to obtain as much historical information about the property as possible.

Other steps you can take include hiring an environmental company for indoor air quality & mold testing, an electrician to check the electrical system, speaking to the RCMP, and of course hiring a home inspector.

For more information, feel free to call me and I’ll point you in the right direction.