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You’ve noticed it, and we have too. The weather is slowly hitting higher temperatures in the GTA. This means high humidity in basements and in general, your home. If you’ve ever walked into your basement and felt like you’re stepping into a sauna, you’re not imagining things.
If you continue letting the humidity fester, it’ll cause odd smells, condensation, and health concerns from mould growth. Here’s an all-in-one guide on how to deal with the high humidity in the coming season and why you might want to give your local basement waterproofing service a call.
Why Is My Basement So Humid?
Humidity refers to the amount of moisture in the air. In basements, high humidity levels often occur because these spaces are underground and surrounded by soil, which naturally holds water. During hot or rainy seasons, that moisture seeps into the basement through walls, floors, and even tiny cracks. Basements also tend to be cooler than the rest of the house. This mix of humid and cool air makes them prime spots for moisture to linger.
Causes of High Humidity in Basements
Here are the top reasons behind high humidity in basements, with added detail on what you can look for on your own before calling a basement waterproofing service near you.
1. Poor Drainage Around Home Foundation
If your yard doesn’t slope away from your home or your gutters aren’t directing water far enough away, rainwater pools near the foundation. Over time, that water soaks into the ground and eventually finds its way into your basement, raising indoor humidity.
How to check: Walk around your house after a rainstorm. If you see puddles forming close to the foundation or water dripping too close to the base of your walls, that’s a red flag.
2. Open Cracks in Basement Walls or Floors
Even small, hair-like cracks in concrete open doors for moisture. These gaps allow groundwater and damp soil vapour to slowly travel indoors, increasing the overall humidity level in your basement.
How to check: Inspect your basement walls and floor with a flashlight. Look for tiny cracks, gaps around pipes or wires, or any signs of staining. You can also run your fingers along the surface to feel for damp areas. This could be a telling sign that there’s a crack nearby.
3. Lack of Vapour Barriers
A vapour barrier is a protective layer (often plastic or foil) that blocks moisture from moving through materials. Without one under your basement floor or behind the walls, moisture from the ground easily passes into the air inside your basement.
How to check: If your basement has a concrete floor but no plastic sheeting underneath, or if you see exposed concrete without any protective covering, there’s likely no vapour barrier in place.
4. Weak Basement Ventilation
Basements often have limited airflow due to fewer windows and doors. When air isn’t circulating properly, any moisture already in the air gets trapped and builds up, creating a damp environment that feels heavy and sticky.
How to check: Place your hand near vents or open windows to feel for airflow. If the air feels heavy, smells musty, or doesn’t seem to move, poor ventilation could be the culprit.
5. Excess Indoor Moisture Sources
Everyday activities like laundry, showering, or even storing wet firewood in the basement add extra moisture to the air. Since basements don’t dry out as quickly as above-ground rooms, the moisture sticks around longer and contributes to high humidity in basements.
How to check: Take note of anything that adds moisture to the space, like laundry drying indoors or stored wood that hasn’t fully dried. Also, look for condensation on windows or pipes, which means the air in your home is holding too much moisture.
Any signs that may indicate these problems are showing up in your home need to be taken note of. That way, you can properly understand what kind of treatment your basement needs.
How To Stop Humidity From Entering Your Basement
The best way to tackle high humidity in basements is through effective moisture control strategies. Here’s how each solution works and why it makes a difference:
1. Install Waterproof Basement Insulation Materials
Introducing waterproof or moisture-resistant insulation to your basement walls is an effective way to block humid air and prevent condensation.
These materials don’t just regulate temperature, they also stop moisture from passing through the concrete and other basement wall materials, reducing the chances of dampness and mould growth. In many cases, they’re part of a complete basement waterproofing strategy that protects your space from long-term moisture damage.
If you need more assistance, it’s best to consult a basement waterproofing company in the GTA for a better understanding of what will work best for your basement.
2. Install Proper Exterior Drainage Systems
Adding French Drain systems or grading your landscape to direct water away from your home stops moisture before it reaches your basement walls. This prevents the soil around your foundation from becoming oversaturated and reduces the chance of moisture creeping indoors.
3. Seal All Basement Cracks and Gaps
Use waterproof sealants to repair cracks in foundation walls and floors. They keep ground moisture from entering your basement.
4. Use Home Dehumidifiers
These handy appliances pull excess moisture from the air while maintaining a balanced environment. Look for models with built-in pumps or ones designed for drainage if you want minimal maintenance during humid months.
5. Improve Air Circulation in Your Basement
Adding vents, using fans, or opening windows (if available) encourages fresh air movement and helps reduce stagnant, damp air. Better airflow also makes dehumidifiers more effective and discourages mould growth.
High Humidity Basement Maintenance
Keep your basement dry and high humidity with these 5 simple maintenance steps:
- Run a dehumidifier regularly: Keep humidity between 30% to 50% to prevent dampness and mould growth.
- Check for water pooling around the foundation: Make sure the ground slopes away from your home, and gutters direct water at least 5 feet away.
- Seal cracks and gaps: Check in walls and floors, even small openings that let in moisture.
- Consistent fresh airflow: Open vents, use a fan, or crack a window to keep air moving and reduce trapped moisture.
- Inspect for signs of moisture monthly: Look for damp spots, musty smells, or condensation.
Do these consistently, and you’ll keep high humidity in basements under control all year long.
High humidity in basements isn’t just uncomfortable; it can lead to bigger problems if ignored. Take action early so you can protect your basement and improve the overall air quality in your home during the summer season!