moldy basement

What Is that Musty Smell in My House?

You’d be surprised how many times we hear that question. The truth is, there is no single answer that applies to every home. You have to do some investigating. Some people may not even notice a musty smell. Every nose is different. But if you, family members, or visitors notice a musty smell, it’s time to get to the bottom of it and do what it takes to get rid of it. Your nose can be very smart… icky smells generally aren’t healthy for your family.

In the vast majority of cases, a musty smell in a house is due to water intrusion from any one of several sources. That musty smell is caused by dampness, building material decay, mold, and mildew growth.

The culprit could be an ineffective HVAC system that is not effectively pulling the humidity out of the air in the summertime. It could also be a leaky pipe behind a wall. In those situations, you’ll want to call a plumber or HVAC company.

What we’re going to focus on today is a musty smell in the basement, a musty smell on the first floor of homes that have a crawl space (caused by foundation seepage), and an open, un-encapsulated crawl space.

Follow Your Nose and Use Your Eyes

If your home smells musty and it’s not due to a leaky pipe or HVAC situation, you want to check out your basement or crawl space.

Musty Smell in Basement

When you open the door from the main floor to the basement and make your way down the steps, are you immediately assailed by a musty smell? If so, you need to go exploring to see where the smell is coming from. Do a visual inspection and a physical inspection.

This includes:

  • Looking for water damaged drywall
  • Looking for discoloration on baseboards
  • Looking for mold and mildew in corners as well as other surfaces
  • Looking for efflorescence (chalky substance) on cement block or cinder block walls
  • Inspecting for rust spots that are caused by carpet tack trip nails
  • Touching the drywall and carpet for signs of dampness
  • Checking the humidity with a handheld humidity meter

The humidity in your basement shouldn’t be higher than 50%. If it is, that’s a good sign that you have water intrusion. And if you see mold, mildew, efflorescence, trickles, or puddles of water,  you have water intrusion.

This is nothing to mess around with. If left to go unchecked, water intrusion and the mold growth that goes with it can affect the air quality in your home and the structural integrity of your home. The best long-term solution for a damp and musty basement is professional basement waterproofing with a French drain and at least one sump pump.

Musty Smell from Crawl Space

If you have a musty smell mainly on the first floor of your home, the culprit could very well be moisture intrusion in your crawl space. The air in your crawl space makes its way into your home. The only way to find out how damp your crawl space is is to get down there and check it out.

You will need a flashlight, and depending on how your crawl space is set up, you may or may not be able to get in there physically. At the very least, shine a strong flashlight in. Can you see standing water? Is the musty smell overpowering? Can you see mold growth? Don’t forget to look UP! On hot, humid days, we have seen open crawl spaces that appear to be raining inside due to condensation on the joist and insulation.

When you have a crawl space, the “floor” is bare earth. That allows ground moisture to seep into the floor studs supporting the first floor of your home, can allow moisture to creep into drywall as well. That’s what causes the musty odor. If your crawl space is ‘open’ and has vents to the outside, then hot and humid air makes its way underneath your home in the summer and condensates on the floor joist underneath your home. This can cause mold growth and decay that creates unhealthy air and smells.

The best long-term solution for a damp and musty crawl space is crawl space encapsulation. This is a process where we completely encapsulate the floors and walls of your crawlspace to keep moisture out. We may also recommend installing a dehumidifier or ventilation device made specifically for crawl spaces.

If you have a musty basement or musty crawlspace, you may want to read up on the issue so that you fully understand what is going on, and what it will take to fix the problem. Neither crawl space encapsulation nor basement waterproofing is a DIY job. Not if you want it to work, anyway.

And it’s important to note that if water intrusion in your basement or crawl space is the source of the musty smell, professional services can mitigate the issue, but since every nose is different, there is no guarantee against smells.


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Schedule a FREE Crawlspace or Basement Inspection

The best way to get rid of a musty smell in your basement or your house is to locate the source and fix the issue. In many homes in the Mid-Atlantic region, the musty smell is caused by water intrusion in the crawlspace or basement.

You may be able to cover up the smell with air fresheners or slap some so-called “waterproofing paint” on the walls, but neither of those addresses the root cause. Protect your home by starting with a FREE inspection from the experts at Value Dry Waterproofing.

Based on what we find, we can develop a customized plan for your home. We proudly serve homeowners in Maryland, DC, northern Virginia, and parts of Delaware.


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