Understanding Relative Humidity in Basements and Crawl Spaces
If you're a homeowner, it's important to understand relative humidity and how it can affect your home. Relative humidity (RH), is the amount of water the air can hold at a given temperature. For example, an RH of 50% means the air is holding 50% of the moisture that it can possibly contain at that temperature. Once RH gets over 100%, it rains. When relative humidity is too high, the air feels damp, sticky, and muggy, and when it's too low the air feels dry.
One of the most common problems in basements and crawl spaces is humid air that condenses and leads to mold growth. Warm air from the outside enters the home and is cooled within the structure. For every one degree that air is cooled, the relative humidity is raised by 2.2%. Mold can grow when relative humidity is above 70%. So let's say the temperature in your basement is 65 degrees. If it's 80 degrees outside with a humidity level of 65%, once the outside air enters the basement the humidity level will increase to 98%. Also, when warm humid air enters the crawl space or basement and touches cooler surfaces like pipes or concrete walls, condensation will occur. Condensation is the process by which water vapor in the air is changed into liquid water.
Most damage in the basement or crawl space itself is obvious, such as mold, rot, wet insulation, wet drywall, and the list goes on. But humidity in the basement or crawl space affects the upstairs too. Since air flows into the upper levels of your home from the basement or crawl space, it brings the humidity from down there with it.
The negative effects of a damp basement or crawl space include:
- Dust mites (the number one indoor allergen)
- Sticking (swollen) doors and windows
- Smelly damp carpets
- Buckling hardwood floors
- Condensation/rotting/mold in your attic
- Frost or condensation and mold on the inside of windows in cool weather
- Increased cooling bills (damp air takes more energy to cool)
- Increased heating bills (damp air takes more energy to heat)
- Mold upstairs
- Decreased life of roof sheathing and shingles
- Decreased life of the paint on the outside of your home
- Aggravated asthma and allergies
The best way to control relative humidity in your home is with proper dehumidification. The SaniDry dehumidifier is 10-times more powerful than a traditional home dehumidifier but uses the same amount of energy to operate. For optimum protection and humidity control in your basement or crawl space, a waterproofing system should also be installed to eliminate any standing water and water vapor.
If you think it's time to do something about your damp basement or crawl space, contact 3 Pros Basement Systems to schedule a free on-site evaluation.
Ready for a no cost, no obligation free estimate? CLICK HERE