There just supposed to be a kind of nasty place, that’s normal, right?

Common does not mean correct or ideal.

As folks who see a lot and go into a lot of crawlspaces, we can assure you the vast majority are not places you want to go or spend much time. Messy, dirty, humid, or wet, full of insects, and hard to get around is absolutely the norm.

But carpet in a bathroom was common too, and we all realized that was a bad idea.

A crawlspace doesn’t have to be all those terrible things, and you’d be better off if yours wasn’t.

If it’s all just down there, though, why does it really matter? If the only time anyone needs to go down there is to fix something, it’s kind of someone else’s problem, right?

Unfortunately, no. The way our houses are built the crawlspace and house are far more connected than they appear. The flooring between the two spaces is far from airtight, meaning whatever is in the air of the crawlspace, be it mold and fungus spores or anything else, is also in the air of the house. The same goes for the humidity; while that space feels disconnected, a very humid crawlspace means a humid house as well.


So, what’s the problem with humidity?

Higher humidity brings with it the possibility of many issues. Lets look a a few of them.


Mold, Fugus and dust mites, all like a humid environment. Small amounts of mold and fugus are present in the air just about always and everywhere. Where they become a problem is when the find a happy environment to grow. To live they need a survivable temperature (above freezing and below about 140), a food source (think most organic materials) and an ideal humidity level (anything about 60%). We require and like to live at the same temperature that mold and fungus do. We also fill our lives with things that make great food sources for mold and fugus, some of those things are out food sources, some are what we wear, somes what we build our houese with. The only line of defense we have is controlling the humidity and keeping it at a level where they can’t live and thrive.

If you want a house thats mold and fungus free you have to keep the relative humidity below 60%. You can make it to dry, the mucus membrane in your nose starts to dry out, and so does our skin at levels below 30% so our sweet spot is about 35-55%.

Humidity also plays a big impact on comfort. If you’ve lived in the South East for any time this doesn’t require any explanation. A warmer dry temperature will feel more comfortable then a mildly cooler more humid one.

Many items in our home swell in high humidity and shrink when they dry, such as wood floors and moldings. If your house maintains a consistent humidity all of your wood products will stay far more stable. This will reduce waviness and cupping in hardwood floors, gaps opening in trim, and those doors that close or don’t seasonally.

Mechanicals last longer with consistant humidity as well. Humid crawlspaces are prone to condensation on water lines, ducts, air handlers, and just about any other metal surface. Which means over time those things tend to rust and fail.

A dry crawlspace leaders to a drier happier home thats more comfortable and healthier to live in.