Making a big stink about odours

Mike Holmes investigates the source of bad smells in a house, and advises homeowners not to ignore them.

You need to put all your senses to work to make your home safe and healthy. That means using your nose to sniff out problems, as well as your eyes to see what’s wrong.

I’m not just talking about noticing and avoiding volatile organic compounds when you smell them (that’s those chemicals in many building products, which evaporate quickly and can sicken some people who smell them). I’m talking about training your nose to recognize dangerous odours that warn of potentially lethal outcomes, such as a natural gas leak, an electrical fire or septic gas.

All these hazards can kill, and they all have a specific odour you’ll probably smell before you see anything. But that’s only if you know the scent when you come across it.

Leaking natural gas, for instance, can smell something like a dead mouse or skunk. Utilities add that unpleasant odour to naturally odourless and colourless gas for the purpose of warning you when it escapes. Ignoring the warning smell and flipping a light switch can cause a spark that ignites the house. Turn off the gas source. Leave the house and call the utility company.

Rotten-egg smell is a symptom of both septic gas, which leaks in through the plumbing, and toxic drywall, which off-gasses hydrogen sulphide. If the house has been vacant for a while, dried-out traps might be letting in septic gas, which is lethal in large doses. If running water through the system doesn’t eliminate the smell, call a plumber. Once plumbing gets ruled out as the source and the smell persists, you could have a worse problem with that bad drywall, which can short electric systems and make you sick. It was imported to North America from 2001 to 2007, so some homes still have it. It must be professionally removed.

Don’t write off a strong urine smell as a pet accident. Accompanied by a stain on a bedroom ceiling, it could also mean a raccoon infestation in the attic. In some cases, it’s a red flag the house might have been used as a lab to make methamphetamine, an illegal synthetic drug. Residue can cause breathing problems, similar to an overgrowth of mould. Decontamination can cost thousands of dollars.

Never ignore a burning smell, either, especially one that’s like burning rubber. Your nose is telling you an appliance or outlet is dangerously overheated, which can lead to a fire. Turning off the circuit you think is causing the problem at the breaker box is a smart first response, before you phone an electrician. But leave the house if you see flames.

Ever catch a whiff of something you can only describe as mushrooms? In an older home, especially where the wood framing wasn’t pressure-treated as it is now, it could be dry rot, a fungus that sucks the structural strength out of healthy timber. To get rid of it, you’ll need a good mould remediator who knows dry rot.

Why am I making a big stink about odours? Probably because so many homeowners ignore or tolerate bad smells, until it’s too late. They never guess it’s affecting their health or, worse, signalling real physical danger brewing behind the walls.

You can’t count on inspectors to identify bad odours unless they actually see evidence of a problem. They’re typically not trained to address a bad smell on its own; it’s categorized as “environmental” and not part of their visual evaluation. A good one, however, won’t ignore smells that, in their experience, are linked to a broader problem.

Some inspectors use dogs specially trained to sniff out mould. Just the way dogs are able to detect drugs, they can smell dangerous mould spores that can affect your indoor air quality and family’s health.

As basic as it may sound, it pays to educate yourself about smells that spell danger. Then you’ll be able to react quickly and call the right professional before things get out of hand.