Basements and crawl spaces are two of the most common areas of mold growth in the home. Many families don’t often spend much time in their basements, and rarely if ever peek into their crawlspaces. This means mold problems in these areas, much like attic mold, are often not discovered until the problem has already grown to a significant size. Yikes!
But do not fear! The trips and tricks in this article will help you deal with any current mold problems you may have in your basement or crawlspace and will also help you prevent any problems from occurring in these areas in the future.
Causes of Mold in Basements and Crawlspaces
Let’s talk about basements first. There are three primary reasons for the prevalence of basement mold:
Foundation cracks leading
After about 20-30 years of age, many building foundations made from concrete begin to see some cracking, which leads to water penetration. (Mold requires water to germinate.)
Humidity and condensation causing moldy concrete
Basements often have cold walls, especially during the winter. When you combine warm, heated indoor air with a cold wall, you can get condensation and mold growth. We see this most around concrete foundation walls, and also in windows during winter months.
Basement flooding and mold cleanup
We see more basement flooding as a direct result of sump pump failure than you can imagine. Be it an old pump that just stops working, or a power outage during a storm, a non-functioning sump pump can cost you tens of thousands of dollars in damage.
Most mold issues in crawl spaces are caused by high moisture and humidity. Consider the location of the crawlspace: it sits underneath your home right on top of the earth. Many crawl spaces have a plastic vapor barrier, but many don’t. Soil and dirt from the earth contain moisture. And moisture is one of two requirements for mold growth (the other being a food source such as the wood that acts as the ceiling of the crawlspace). And since moisture forms so easily in confined areas, dirt crawl spaces are fertile breeding grounds for mold.
Mold Remediation in Basements and Crawl Spaces
Eliminating Mold Caused by Basement Foundation Cracks
A crack in the foundation will often lead to a small water leak along the perimeter wall of your basement (eventually getting bigger over time), which will dampen the local interior drywall, which will then lead to moldy drywall. The best way to fix a crack in your foundation is open up the walls, thereby exposing the crack in the concrete, and have it sealed and filled by a qualified mold remediation professional.
Eliminating Mold Caused by Basement Condensation Issues… Attention DIY-ers!
This type of mold is most often surface mold growth along painted concrete walls. Since there’s usually no demo of drywall required, this mold elimination can usually be done by a handy homeowner.
We recommend buying two types of cleaning agents from the local hardware store:
- One that kills the mold like Concrobium Mold Control, and
- A cleaner that helps to remove the staining from the mold like Clorox Cleanup.
These can be powerful chemicals, so wear a mask and gloves and keep the area ventilated. If you’re not comfortable doing this, then please hire a mold professional. Not sure if you can do it yourself, read more about when you need to hire someone.
Eliminating Mold Caused by a Flooded Basement
**IMPORTANT: If your sump pump fails and you’ve got a flooded basement, you MUST contact a professional water damage and dry-out company within 24 hours so they can bring in their equipment to rapidly dry the basement. In other words, eliminate the mold before it has a chance to grow.
If it’s too late to dry out the property, the wet drywall will need to be cut out and you’re looking at costly mold remediation work and rebuild. Many homeowners are covered for this type of water damage by their homeowner’s insurance, but trust me, you don’t even want to go there. It’s a massive headache to deal with the construction work and fighting with the insurance company.
Eliminating Mold in Crawlspaces
Mold in crawl spaces is usually painstaking to remediate. There’s no demo to be done, but it requires detailed HEPA vacuuming, spraying and scrubbing of the wood in a very tight/confined space. Not fun!
Preventing Mold in Basements and Crawl Spaces
Preventing Mold Caused by Basement Foundation Cracks
There’s not much you can do to prevent a foundation crack because they come as the home ages. But you can certainly keep the problem at a minimum by walking around the outside perimeter of your home, making sure that there are no pools of water collecting against your house and making sure that your gutters drain at least 6 feet away from the house (you can buy gutter extenders to accomplish this).
Preventing Mold Caused by Basement Condensation Issues
There are two methods to prevent mold growth in your basement caused by moisture and condensation.
Try anti-mildew paint in your basement
Re-paint your concrete foundation where you’re experiencing surface mold growth with an antifungal paint such as KILZ (there are many). These types of paints advertise that they prevent mold growth on the surface of the paint. In my experience, they don’t always work, though.
Insulate your foundation to prevent condensation
The second thing you can do would be to insulate your concrete foundation walls. There are many different options: Styrofoam, spray-foam, or finishing the basement. Insulated walls would prevent that difference in temperature that causes condensation and mold growth.
Preventing Mold Caused by Basement Sump Pump Failure
In a nutshell…don’t skimp on your sump pump system! Buy the best pump you can afford and make sure to also install a battery backup system.
Many homeowners don’t really know what their sump pump does or how exactly the sump system works, which is critical to understanding why a quality sump system is important.
What is a sump system, and how does it prevent flooding?
A sump system is basically a drainage system. There are drain pipes around the perimeter of your home’s foundation that lead groundwater into your sump well The drain pipes prevent groundwater from forcing its way through your foundation via cracks. The water is then “ejected” from the well, usually to the outside far away from the house, by your sump pump.
When a sump pump malfunctions, your drain pipes are basically one-way rivers of water directly into your basement. You’d be surprised at how fast your basement can flood!
Buy the best sump pump you can afford to prevent flooding
Sump pump malfunctions can be caused by both a broken sump pump and a power failure, such as during a storm. We recommend buying the highest quality sump pump your money can buy. Trust us – don’t skimp on your sump pump. It’s not worth saving $100 when a broken sump pump can cause tens of thousands of dollars in damage and a massive headache. We also recommend installing a battery back-up system. They are expensive, but they are worth it.
Think about it – it is not a matter of if but when the power goes out because of a storm. Don’t lose sleep over a power outage; get the battery backup and keep your basement dry and mold free.
8 Steps to Prevent Mold in Crawlspaces
Here are some handy tips for preventing mold problems in your crawlspace:
- Check the foundation walls and make sure there are no cracks where water can enter.
- Make sure gutters and downspouts channel at least 6 feet away from the house, especially during the rainy season. Otherwise, water can accumulate near the house and eventually find its way inside your crawlspace.
- Check for adequate ventilation. At a minimum, there should be 1 square foot of ventilation for every 150 square feet of crawl space area. We are big fans of well-ventilated crawl spaces.
Note: Many building professionals advocate closing vents and controlling moisture through other means, arguing that open vents make it difficult to keep crawl spaces warm in winter, and can lead to increase in moisture build up in the summer when hot humid air is brought into the crawl space. These are good points, but it can be challenging to control moisture through other means without the use of vents. In addition, once mold starts to grow, it is going to spread much easier in closed spaces without vents relative to closed areas with vents. The outside fresh air coming from the vents can also help dry out a structure and reduce the concentrations of mold in the air once the outbreak occurs.
- In vented crawl spaces, insulate tightly against the subfloor. Secure the insulation snugly with mechanical fasteners. Do not just stuff the insulation up in the sub floor between the joists and hope it stays put. It will likely fall out eventually without fasteners.
- Make sure existing insulation is not missing or sagging, both of which can suggest you have a water problem.
- Make sure there is a plastic sheeting vapor barrier that covers the entire dirt crawl space and goes up a few inches alongside the foundation walls. There should be plenty of overlap between the layers of sheeting and the sheeting should be absent of any standing water. If done correctly, plastic sheeting will serve as an important vapor barrier in your crawlspace.
- Look for leaks around HVAC ducts and plumbing components.
- Dryer vents should terminate outside of the house and NOT into the crawlspace.
DIY may be an option, but always be safe.
We hope that the above tips and tricks will help you eliminate and prevent mold growth in your basement or crawlspace. Hopefully you can do some of the work yourself to save some money, but remember, safety first! Some of these areas can be very challenging to work in, such as the crawlspace. Check out our DIY Mold Removal support page to see how we can help you with your project.
If you’re not comfortable doing the work yourself, don’t take any chances and just hire a professional. It’s not worth risking your safety to save a few bucks.