Mold that you find growing in a basement, generally begins with a poorly constructed foundation wall. If a foundation wall is constructed of concrete block there is a greater chance of finding problems, concrete block is porous and contains cavities that collect moisture, that moisture over time eventually finds the path of least resistance, entering a home either through the blocks, or through cracks in the mortar joints of the foundation wall. Poorly constructed (older)poured concrete foundation walls can also allow moisture through them. Generally, newer foundation walls do not allow moisture through them since they are protected with either a plastic drainage layer around the perimeter of the foundation or backfilled with clear gravel that allows surface moisture to travel to the weeping tile where it either discharges via sump pump to the storm sewer system or to grade away from the home. Moisture that finds it’s way into the basement may develop into mold, particularily in areas that are dark, damp, with stagnant or still air.
Recently I was hired by a couple to conduct a foundation inspection on an older home that they were hoping to purchase. They were particularily concerned with the foundation. The last home that they purchased, they didn’t hire a Home Inspector, months later found out that the foundation wall leaked. A few things began to tip me off that I may discover a problem, one of the exterior poured concrete foundation walls had 6 mill Poly Vapour Barrier affixed to the exterior of the foundation wall almost 1 foot above grade, newer homes have a drainage layer surrounding the perimeter of the home, the plastic indicated that someone had made an attempt to keep moisture out of the basement. I walked into the basement and found that the dehumidifier read 65%, and was running on high, there was a tinge of odor in the air. When I glanced at the baseboards, they appeared discolored, then I touched the carpet and baseboard they were both damp. I pried the baseboard back a bit, to find black mold. Upon further investigation of the basement, there was quite a bit of black mold, indicating moisture leakage for some time. It’s too bad since this couple had already fallen in love with the home. They asked me what it would take to get rid of the mold, I explained that getting rid of the mold was the easy part of the problem, the main issue was to prevent it from happening again, and the only way to do that was to excavate around the perimeter of the home and install a drainage layer, and possibly a sump pump, to make the basement dry.
Most species of mold are relatively harmless. Only 6 to 10 percent of the general population, are sensitive to mold, For these people, exposure to high levels may lead to rashes, watering eyes, runny nose, coughing, sinus congestion, difficulty breathing. There’s also a higher incidence of mold allergies in asthmatics. People with compromised immune systems and those with established lung disease may experience a higher reaction to mold.
Some molds are considered toxic, even to healthy people. Toxic molds produce chemicals called mycotoxins, which may cause serious illness, infections, commonly called “black mold” many of these, such as the greenish-black Stachybotrys mold and its cousin, Memnoniella, grow on popular building materials such as sheetrock, wood and paper.
If you discover mold, “do not panic”, even if it appears black. You should, make an immediate plan of action to remove the mold while employing sensible safety procedures during the clean up. Most basement mold cleanups are something you can do yourself, as long as you feel capable of removing materials and performing the repairs yourself. If the mold covers the entire basement or if you suspect it’s growing in areas you feel uncomfortable handling, such as inside air conditioning vents, consult a mold remediation professional instead.
Mold Removal Tools
- Plastic tarps.
- A respirator.
- Spray bottles.
- Disposable rags or paper towels.
- Large garbage bags.
- 5-gallon buckets.
- Rubber or latex gloves.
- Measuring cup.
- Borax or vinegar.
- Commercial-grade HEPA vacuum, if possible.
- Full clothing, such as coveralls.
- Goggles or similar eye protection.
- Scrub brush or broom.
Mold Removal Preparation and Safety
It’s too late, once you’ve entered your moldy basement, to realize you forgot things you need and then make endless trips back and forth to the rest of your home. Proper preparations and gathering the things you need before you attack are critical. Permit yourself one inspection trip, armed with personal safety equipment, to determine the scope of the problem and to eliminate the source of moisture if possible.
If the basement is wet from a flood, the source is obvious. Other possibilities include gutters ending too close to the house, improperly graded soil around the house, leaks in the foundation, a dryer that isn’t vented to the outside, and leaking pipes, among others. Closely examining the area of mold should quickly reveal where the water is coming from. Then, take steps to eliminate the source. Call in a professional for foundation issues or other repairs as needed. Only after the problem is resolved will you be successful in eradicating the mold. All it takes, after all, is a single spore to grow into a colony again.
Once you’ve stopped the moisture, hang sections of plastic sheeting over door openings and heating or air conditioning vents to isolate the infected areas from the remainder of the basement or house. At this point, there’s less mold outside than indoors, so open a window, if possible, to provide ventilation and fresh air circulation. A fan, set in the window and pointed outside, or aimed at the ceiling, will also help circulate the air. Avoid blowing it directly at the mold or turning it on high, which will stir up the mold and encourage it to release spores.
Consider running a heater or dehumidifier at this point to aid in drying out the basement. If you do, wipe the appliance down with a disinfecting mold cleaner when you are done with the removal to prevent recontaminating your home.
Mold Removal Solutions: Borax and Vinegar vs. Bleach
Here’s the truth about expensive mold removal solutions and bleach: You don’t need them. If the mold is growing on removable items such as drywall or boxes stacked on the floor, much of it is removed simply by discarding contaminated objects and replacing them with fresh material. Then, scrubbing the surroundings with detergent and water or a natural product removes the mold residue. It’s cheaper than commercial fungicides and doesn’t burn your eyes, lungs and skin like bleach.
If your basement flooded, it’s still a good idea to use bleach to sanitize it. Bleach reduces the mold count – it doesn’t completely kill it – and neutralizes harmful bacteria. Mix chlorine bleach with warm water in a bucket at a ratio of one cup (8 ounces) of bleach per gallon of water. As you use the bleach water and it becomes dirty, flush the remainder and mix fresh solution.
A better choice for removal is either straight vinegar for smaller areas or borax and water for larger areas. Sure, vinegar has strong fumes, but they will dissipate within a few hours. Borax, another completely natural product, leaves a powdery residue behind as it dries, which will repel mold spores before they begin to grow. Mix about 1 cup of borax per gallon of warm water in a bucket and refill a spray bottle as necessary.
Getting Rid of the Mold
So you’ve found the source of moisture, fixed the problem and dried out the basement. You’ve gathered your tools, chosen a mold removal solution and donned your protective wear. It’s time to give the mold in your basement eviction papers.
Look for mold not only on exposed surfaces, but also in cracks and crevices surrounding the source of moisture. Whenever you find mold, spread your search farther than the original spot. In many cases, visible mold turns into invisible or hidden spots of contamination.
An unfinished basement is likely the easiest cleanup. Remove boxes, bags and other items stored in the area. Place them in garbage bags to contain the mold until you can remove them after you are done cleaning the basement itself. Finished basements are a little more complicated. You may need to tear away wall sheathing – drywall, paneling or similar – to expose the wall interior. Throw away sheathing or insulation that comes in contact with mold. There’s no good way to clean it.
Rip up carpets and other flooring material if you suspect mold underneath. Mold growing in hidden spots under you walls, in your ceilings or under your floors will only continue to grow. If you tear it up and find it’s okay, often you can reuse the material after wiping it down with solution or steam cleaning the carpet. If you do find mold, however, just throw it away. The cost to replace it is insignificant in comparison to your family’s health.
After removing and bagging all furniture, decorations, boxes, stored items as well as any building materials, it’s time to treat the surfaces to kill what remains. Fill a spray bottle with vinegar or borax and water. Spray the walls, pipes, windows or other permanent fixtures until they are thoroughly coated with the solution and allow it to set, penetrating the mold and basement surface, for an hour or two. Once the mold is damp, it’s unlikely to release any spores. Take advantage of the break to slip out of the basement, removing your protective wear before you walk through the rest of the house, and carry the bagged items outside.
When you return to your basement, spray the surfaces down again to refresh the mold-killing properties. Spray past the contaminated surfaces – overdoing it is better than leaving spores to grow again. Use a brush on vertical surfaces such as walls, wood framing and windows to scrub the moldy surface. Rinse brushes frequently in fresh solution to prevent re-contamination. Scrubbing physically removes much of the now-dead mold. Try a broom on floors or hard-to-reach spots and switch to cloths as needed.
Now that the mold is dead and scraped from the surfaces, you must remove it from the property. Scrubbing and wiping with fresh water is tedious, but effective. Go over the area repeatedly, changing your rinse water every few minutes.
If you used borax to clean the mold, lightly spray the surfaces one final time. Then, when you are satisfied that every contaminated item and area has been removed, cleaned and thoroughly rinsed, you must allow your basement to dry. It can’t be stressed enough: You can’t allow moisture in your basement. Wipe down treated surfaces with clean rags to start. Ideally, purchase a dehumidifier, if you don’t already have one, and set it up in the middle of the area.
After the basement is dry, repair and redecorate it. Install new insulation, sheathing and flooring if necessary. Replace items removed from your basement during cleanup (provided they are mold-free). Just take your time in treating, rinsing, drying, and repairing your basement at all costs. The best job comes when you take the time to do it right, and with mold, rushing generally results in an unwelcome, permanent guest.
Preventing Mold’s Return
You’ve evicted the mold, but that’s not enough. More is sure to come if you don’t take steps to keep it away. Remember, mold needs a source (spores), food (anything from biodegradable building products to simply dead insect parts and skin particles drifting in the air and settling on surfaces), water, hospitable temperatures and darkness. So your job is to eliminate as many of these factors as you can.
Modern buildings are often energy-efficient and relatively airtight. Any source of moisture, from over-watering plants to leaks, should be eliminated. This is especially true in the basement, where temperature differences between the upstairs and downstairs encourage the formation of humidity and condensation. Running a dehumidifier year round and installing vents, especially in the bathroom, helps significantly.
Install a hygrometer to monitor your relative humidity in the basement. Humidity levels above 50 percent indicate the environment is ripe to grow mold. When used in combination with a dehumidifier, it can also tell you when you may have a moisture problem. That is, in a temperature-controlled environment with a dehumidifier running, your RH levels should remain fairly stable. If the level suddenly rises, you should suspect you have a leak or other moisture source and investigate.
The temperature in your basement should be almost the same temperature as the rest of the house during the winter months. Heating your basement helps to maintain consistent relative humidity levels.
Your basement is now mold free and leak proof, hopefully!!! Not only should it look much better, but it’s healthier and you saved a lot of money by doing it yourself.