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Do You Smell That? What Your Basement Odour Is Trying to Tell You

illustrated nose smelling

Musty. Grassy. Sweaty. Stinky. Like Halloween (think decomposing remains, not treats).

These are the smells that send homeowners scrambling to find their phones to call us.

Typically, by the time we get that call, the homeowner has tried everything to get the smell to leave quietly. Candles, essential oil diffusers, odour eaters, plug-in air fresheners, incense, you name it – these temporary bits of help may mask the stench for a day or two, but then it comes right back stronger than before.

This is because the odour isn’t caused by an introduced activity, such as cooking fish in the kitchen. It is caused by – and coming from – the space itself.

When your basement starts to emit its own signature fragrance, you can think of it as an S.O.S. Something is wrong and it isn’t going to fix itself. In this blog post, find out exactly what your basement odour is trying to tell you and how to fix it fast.

My Basement Has a: Grassy, Sweaty Smell

If your basement smells like it is harbouring an entire sweaty team of teenage football players, or your first thought is “who left their dirty socks down here,” what you are smelling is likely mould and mildew.

Over the years, we have been genuinely amazed at these opportunistic fungal spores. Just when we think we have seen every possible place a mould colony could hide, we see something new.

The basement is a common target for mould and mildew spores to set up shop. It is often cool, damp, humid, dark and somewhat neglected. Typically it houses a nice selection of organic matter in the form of cardboard storage boxes, old linens and holiday decorations.

If the family washer/dryer is housed in the basement, that is just a bonus – more humidity means more mould!

How to fix this

Mould can usually be spotted unless it has colonized behind your drywall. In this case, the smell may be your only warning sign. A mould test can confirm what type of mould you are dealing with. All the mould must be removed before your basement can be sealed and waterproofed.

My Basement Has an: Animal Aroma

Does your basement smell like wet dog or dirty kitty litter but you don’t own either pet?

Unless the neighbour’s pets are using your basement as a latrine, the most likely culprit is intruding wildlife.

Raccoons, mice, rats, skunks, opossums, squirrels and other small mammals adore basements. They are comfortable, dark, full of interesting edibles (if you consider electrical wiring, cardboard or insulation an edible), often a great source of water and safe from predators.

Once the local wildlife has figured out a way into your basement space, you may not see them with your eyes, but you can definitely smell them.

How to fix this

Interior basement waterproofing and encapsulation is the best way to keep unwelcome visitors out permanently.

Otherwise, your only other option is kind of like sticking band-aids all over your basement as you find and fix one entry hole and then another. This approach is very temporary, inherently imperfect and guaranteed to be highly unpleasant for both you and your furry guests.

My Basement Has a: Swampy, Sewer Scent

Did you know that some bacteria like to eat iron? Iron-oxidizing bacteria eat iron for breakfast...literally.

When they do, the swampy sewer scent won’t be your only or even your first indication. Most commonly, basement owners notice iron bacteria when they see a rust-coloured ooze (called iron ochre) spreading out from around iron-containing fixtures or structures.

How to fix this

The slimy remains of an iron bacteria’s dinner may look like a simple unsightly mess, but it is actually potentially far more serious. This ooze can work its way into your plumbing, foul your drinking water and even stop up or rot out your sump system and drainage pipes.

If you see only a small amount of iron ochre, it doesn’t necessarily mean there isn’t more. The best solution here is to have your basement tested for iron bacteria (which unfortunately is quite common).

A positive test requires immediate action, which may range from rerouting your drainage system to an affordable basement waterproofing treatment made just for iron ochre bacteria-infested basements.

My Basement Has a: Musty, Rotten Egg Odour

There is a reason power companies add rotten egg-smelling methyl mercaptan to natural gas. It is the only way customers will know there is a gas leak!

And if there is one thing that can make rotten eggs smell even worse than they already do, it is neglect with a side of humidity.

If your basement has also tested positive for iron bacteria, you may need an additional test for sulphur bacteria. These two tend to stick together because iron bacteria paves the way for sulphur bacteria to feed, thrive and spread.

How to fix this

A musty, rotten egg odour is always worth paying attention to, regardless of the cause. The treatment will depend on whether your gas provider confirms and fixes a leak, after which the odour should cease.

If this does not apply, the next step is to follow the fix outlined in the previous section and have your home tested for iron bacteria and sulphur bacteria.

Get in Touch

Is your basement sending up a stinky S.O.S.? We can help! Contact us now to take action and protect your basement, sump pump, plumbing and home before another Canadian winter sets in.

Our Easy Quote service provides you with a free, no-obligation inspection and quote so you have the information you need to take the next steps.

Contact us online or give us a call at 1-866-875-6664.

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