How to Control Moisture in the Basement?

Last Updated on

Problems with moisture control in your basement or crawlspace? Here’s how to control it and solve the problem for good. Read on!

Have you ever walked into your basement and wondered why it looks and smells different compared to other areas in your home? A common problem for basements is moisture accumulation leading to mold and mildew growth. Hence, you will find carpets and wall coverings damp and on the road to damage and breakdown. 

What's Inside?

Is Moisture in the Basement Common?


Moisture in the basement is common but not normal. The basement, like all the other parts of your home, should not be moist-filled because it does not make it a place conducive for humans, but rather, a good breeding place for bacteria, mold, and mildew. 

Where Does Moisture in the Basement Come From? 

water source

If you want to correct and totally eliminate moisture from your basement, you have to know its source. There are three main and common sources of moisture and these include the following.

  • Rainwater or groundwater
  • Interior moisture from unvented dryers, steam from cooking and bathrooms, post-construction moist and humidifiers
  • Humid air coming from the outside of the basement condensing in colder surfaces involving the processes of vapor diffusion, liquid water flow, air movement, and capillary suction

What are the Signs of Moisture Build-up in Basements?


Whether you realize it or not, you may have already encountered these signs but didn’t know that they were a part of a bigger problem. It may have started with standing water on floors, walls with trickling water, damp or saturated concrete block walls, and damp and humid air.

You may notice build-up of mold, mildew, foul odor, carpet or wood deterioration, efflorescence, or concrete or masonry spalling, blistering or staining of wall coverings. It may escalate to the decay and rot of joists, columns, sill plates, or wood headers, and the presence of condensation in floors and walls during summer. 

What Causes Basement Moisture Buildup?

wall crack

Moisture buildup can be caused by structural cracks

Your home’s foundation needs periodical maintenance as its materials deteriorate over time. Neglect of regular checking can lead to crack development in areas such as concrete, concrete block foundations, fireplaces and floor joists.

To prevent this from happening, it is recommended to make sure that you have a proper footing design and connection between above structures and the foundation wall. Ensuring this prevents the likelihood of cracks and moist buildup.

Moisture buildup can be caused by missing or malfunctioning downspouts and gutters


When you have defective downspouts and gutters, rainwater can be misdirected and may end up in the foundation perimeter. Do remember that the lack of splash block or extender can cause more damage than having none at all. Think of it as directing all the water into a concentrated area close to the basement.   

To address this, it is recommended to put one or more downspouts per fifty linear feet of the roof eave. This can direct and drain water at least four feet at a distance from the wall. It has been proven that concrete sidewalks that are sloped found around the basement area is effective in facilitating a good rain drain. 

Moisture buildup can be caused by window wells that are poorly designed

Some of the homes with problematic basements have inefficient window well designs. Their window wells are usually built to direct water toward, instead of away from the foundation. Filling the window wells with a ⅜-¾ inch of construction aggregate from the footing usually solves the problem. 

Moisture buildup can be caused by inadequate grading

Most of the time, foundation that is surrounded by ground that is level or sloping toward the house can end up with water as it is directed to the basement instead of away from it. This is usually because the soil lacks proper backfill and compaction which then causes settling.

A good solution to this would be to add soil around the house, do it in a way that it slopes away from the foundation instead of toward it. You can use a guide with a minimum of 1 inch per foot to at least 6 feet.

What Can Solve Moisture Buildup in Basements?

There are a couple of things that you can do to address the situation. There are short-term and long-term solutions that you can choose from. Use them accordingly and make sure to check out approaches to prevent this from reoccurring or aggravating. 

Dehumidification can provide a temporary solution


If you already have a problem with odor, humidity or dampness in the basement, you can opt to use dehumidifiers. However, according to, this can be a temporary go-to as long-term usage of this can cost you more because of the possibilities of efflorescence and spalling on concrete and other interior finishes. 

Determine the root of the problem

Stated above are the common causes of moisture buildup in the basement. To come up with an effective and strategic plan, you have to determine the cause of the build-up. From there, you can proceed with steps starting from low-cost to more expensive measures to solve it. 

Remove excessive interior moisture sources

basement ventilator

Sometimes, removing a couple of interior moisture sources does the trick. This includes steam coming from bathrooms, clothes dryers, cooking, and humidifiers. If you promote proper ventilation and exhaust for those, you will be seeing a slight improvement in the situation. 

Condensation can also be a problem, especially during summer. Since the weather is already hot, it is not recommended to ventilate the basement with humid and hot air. Sometimes, installing a good air-conditioning unit can do the trick.

Moisture buildup in the basement is a problem faced by most people around the globe. There are a lot of things that may lead to this. This situation can sometimes start smell and be a creeping problem that eventually develops into a bigger one. While some are easily managed, some would require complex changes. 

The key to effectively addressing this would be to fixing the gutter, downspout and grading systems. Facilitating proper ventilation and eliminating interior moisture sources can help too. And lastly, installing a proper exterior and interior drainage system can prevent it from happening again. 

Related reading:

Read more

Read more

Read more

Read more