A damp basement isn’t just a basement problem; it can impact your quality of life throughout the home. Thanks to a phenomenon called the ‘Stack effect’ (or the ‘chimney effect’) the negative consequences of damp, mold and bad smells can and probably will spread.

The Science Behind Indoor Circulation

Basements form the foundations of your home. As well as offering a handy space to store junk you can’t quite bare to throw out, they underpin the whole house. Unfortunately, we all too often shut the door and don’t think about what’s going on down there until we need to sort through the boxes for something.

This means that when they get damp (more on how that happens later), it all too often sits there. Combine this with generally bad ventilation and you have the perfect conditions for mold, mildew and humidity.

Thanks to the stack effect, this warm, humid air is drawn up through the house. It’s the same mechanism that makes a chimney work, and just like a chimney, it’s not just hot air that rises. Spores from molds and mildews, musty smells and other pollutants will be drawn up through the building too. The impact on your home’s air quality is obvious.

The only reliable way to avoid these contaminates from spreading is to deal with the issue at source. Addressing the causes of damp in your basement will dramatically improve your indoor air quality.

Common Causes of a Damp Basement

There are numerous sources of water in your basement which can cause issues to spread around the home:

● Groundwater seepage. The soil surrounding your home always contains a certain level of water. If there are cracks in your basement wall or floor, it’s likely that it’ll find a way through. Even if there are no cracks, concrete is relatively porous and if there’s enough pressure, it’ll seep through.

● High humidity levels. Basements tend to be pretty badly ventilated. This means that humid air can become ‘trapped’ and build up over time, leading to increased humidity levels down there.

● Leaky plumbing. It shouldn’t come as any surprise that leaky plumbing leads to a damp basement. Water escaping pipes has to go somewhere.

● Improper drainage. Gutters, grading, sump pumps, interior drainage systems- there are a number of systems that serve to keep your basement dry. If any of them fail or lose efficacy, the result is obvious.

How a Damp Basement Impacts Indoor Air Quality

Damp basements spread the effects through your home. Particularly notable problems include:

Mold and Mildew

Moisture creates the perfect breeding ground for various fungi like molds and mildews. These reproduce by sending out spores into the air. When caught up in the ‘stack effect’, these will be carried through your home- sometimes they’ll gain a foothold in other areas too such as walls, carpets and even your HVAC system.

These spores carry with them certain health risks, particularly for people who suffer from asthma, allergies or respiratory problems. They’ll even, if the concentration gets high enough, damage the health of otherwise healthy people.

Musty Odors and Volatile Organic Compounds (VOCs)

That musty ‘basement smell’ – a sweet, earthy stench- comes from microbial growth, molds and things starting to decompose. Not only is it unpleasant, it can bring with it volatile organic compounds, which contribute to poor health.

In strong enough concentrations VOCs can cause:

● Headaches

● Nausea

● Organ damage

It’s even been suggested that some of these compounds are linked to cancer.

Increased Dust Mites and Allergens

Humid environments, especially dusty ones, make excellent habitats for dust mites. These tiny creatures are notorious for triggering allergies.

It’s not just the tiny creatures you have to worry about: any allergen in the basement might be caught up in the airflow and spread around the home.

Increased Risk From Radon Gas

Though not directly linked to dampness, Radon gas can enter the home through much the same methods. This gas is always around us, released by the soil and rocks in the ground, and in smaller quantities is basically harmless.

In spaces like basements however, this gas can become concentrated and becomes a real health risk. Radon is the second biggest cause of lung cancer after smoking, so it’s worth taking seriously.

How to Improve Basement Air Quality and Reduce Moisture

Avoiding these issues is largely a matter of keeping your basement as dry as possible. There are a few issues you should address:

Waterproofing Solutions

The most obvious thing to do when dealing with a water related problem is to improve your waterproofing. This could take a number of forms, depending on the severity and root cause of the issue.

Water is a fact of life and most waterproofing aims to control its flow rather than try and stop it entirely. Installing French drains, sealing cracks and applying waterproof coatings are all worth considering, as is installing a reliable sump pump system.

Improve Ventilation and Dehumidification

One of the leading causes of dampness in basements is the generally poor level of ventilation. As we tend to leave them closed up most of the time, air doesn’t circulate from opening windows and doors in the way it does in the rest of the home. This leads to humidity getting trapped and building up.

There are two ways to tackle this: employ a dehumidifier or install vents and exhaust fans to remove moisture from the air and ensure better circulation.

Fix Drainage and Plumbing Issues

It goes without saying that repairing leaky pipes and avoiding standing water on your basement floor should be a priority. These leaks can and will get worse the longer they’re ignored and can cause more pressing damage than a reduction in air quality (though this shouldn’t be ignored either).

Drainage issues should also be dealt with. It may be counterintuitive but perhaps the most important thing to check here is your guttering. These and the connected downspouts conduct rainwater from your roof away from your basement walls. Issues here can lead to water finding its way inside, damaging your home and its air quality along with it.

Install a Vapor Barrier

A vapor barrier creates an impenetrable layer between your basement space and the dampness that can penetrate walls and floors. This effectively stops the effects of moisture seepage, though it should generally be employed alongside other methods such as dehumidifiers and sump pumps to reduce the strain.