Why Does My House Smell Musty?

If your house smells musty, the smell is usually not coming from the room you are standing in. It is coming from under your feet.

The three most common causes are bio growth such as mold or mildew, standing water that has gone stagnant, and cheap crawl space materials breaking down and off gassing.

All three live in the same place. Your crawl space.

Why a smell down there becomes a smell up here

It is called the stack effect, and it is simpler than it sounds.

Warm air rises and escapes through your attic. When it leaves, it creates a vacuum, and that vacuum pulls air up from the lowest part of your house to replace it. That means air from your crawl space is being drawn up into your living room, your kitchen and your bedrooms all day long.

Whatever that air is carrying comes with it. Mold spores, mildew, pollen, dust, debris, odors. It does not stay under the house. It ends up in the room you are standing in, and in your lungs.

Studies have found that a significant share of the air inside your home originates in the crawl space. That is why a problem down there does not stay down there.

Cause one: bio growth

Mold and mildew need moisture. Once relative humidity under your house climbs above sixty percent, you have an environment where they can thrive, and North Carolina gives them plenty of chances to.

I am not a doctor and I cannot give you medical advice. What I can tell you is that I am a crawl space expert, I see mold in crawl spaces every single day, and I would not want it under my house.

Cause two: standing water

Water that sits does not stay clean. It goes stagnant, and stagnant water smells.

It gets under there a few different ways. Sometimes it is humidity condensing. Sometimes it is bulk groundwater pushing in under the footer or through the foundation walls. Sometimes your vents sit low enough to the ground that water comes straight in through them. And every so often it is a broken or leaking pipe.

Cause three: the materials somebody else already installed

This one surprises people, because they already paid to have their crawl space handled.

There is a material used very commonly in this industry that absorbs moisture and then begins to delaminate, which is a technical way of saying it comes apart. As it breaks down it off gasses, and that produces a musty or sharp ammonia type smell.

So a homeowner can have the work done, be told the problem is solved, and end up with a brand new smell a couple of years later. If that is your situation, it is fixable, and it is not your fault.

How to figure out which one you have

Honestly, you probably cannot from up here, and I would not want you crawling around under your own house trying.

When I come out I go through the entire crawl space and take photo evidence of everything I see. Then I show you the pictures and tell you what is actually going on down there. Sometimes it is one thing. Sometimes it is humidity and water and old materials all at once, and then we talk about what order to fix them in.

Either way you get the truth about what is under your house and what it will cost to deal with. Then you decide what you want to do about it.

If your house smells musty and you want somebody to actually look, call me at 910 580 1836.