Mold and mildew are not friends to old houses. Whether they show up indoors or out, they need to be eradicated wherever they show up. Determining the difference between mold and mildew is not exactly the easiest task.
The good news is that the treatment of both mold and mildew is very much the same, so a diagnosis isn’t always necessary. That being said, learning to discern between a dirty surface and a moldy surface is important.
In this post, I’ll show you how to figure out what you’re dealing with, how to kill it, and how to make sure it doesn’t come back again. Won’t that be nice? Read on for the details!
Mold vs. Mildew
While the names are used almost interchangeably these are two slightly different things. Mold and mildew are both fungi but they present in different ways and create different issues.
Mold
Mold is a fun-guy! No seriously, it’s a form of fungus that can grow about anywhere it finds the right conditions. What are the right conditions?
- Warm temperatures
- Oxygen
- Moisture
- Food source (almost anything organic).
It needs all four of these conditions to exist before it will grow. Mold spreads by microscopic spores that are floating almost everywhere. They hitch a ride on our clothes and other materials and settle on some flat surface where they wait for the perfect combination of the right conditions listed above. Mold is useful in nature because it breaks down old trees and other material, but not so valuable in our houses because it can make us sick and cause structural damage.
Mold appears in a multitude of colors like black, brown, rust, mustard, green, and many more since there are thousands of different kinds of mold. It usually presents itself like a blotchy appearance on surfaces and gradually fills in to cover the entire surface if left unchecked. Mold is a danger and should be resolved immediately if discovered.
Mildew
Mildew is basically a type of early stage mold that grows flat on surfaces where there is excess moisture. Mildew appears most often on surfaces like shower walls or window sills where there are high moisture concentrations. It has a dusty or light grey appearance at first but can turn darker if it has time to mature. Just like mold it needs warmth, moisture, oxygen, and a food source to grow.
Mildew creates a musty smell just like mold, but it poses very little health risk to humans and very little risk of damage to the surface it is growing on. To me mildew is a more of a cosmetic issue and an inconvenience rather than a problem.
How To: Get Rid of Mold & Mildew
So, how do you get rid of mold and mildew if you discover it? The treatment for mold and mildew is very much the same except in extreme cases. If you have large areas of toxic mold then it’s best to have a professional handle the clean up. For small areas and preventative purposes follow the instruction I outline below.
For just about any mold and mildew problem there are a multitude of cleaners on the market. One of my favorites is Jomax Mold and Mildew Killer. You simply dilute with water, spray or brush it on the surface needing treatment, wait a few minutes until the mildew disappears, and then rinse the surface with clean water.
You can go with Jomax or any of the myriad other cleaners or you can go the old-fashioned way which works just as well. Mix your own mold and mildew killer by mixing 3 parts water to 1 part bleach. For really tough areas try the more concentrated mixture of 1 part water to 1 part bleach. Keep in mind that whatever cleaner you use it likely already has some kind of bleach or bleach alternative in it so rugs and other materials can be damaged if they get the chemicals on them.
Some areas may be more problematic than others and may require treatment a couple times before the problem is resolved so you’ll have to judge for yourself if one treatment did the job. Another option for larger infestations is to spay the cleaner on the surface and scrub the surface with a firm bristle brush or scrubbing pad and then rinse the surface.
No one can avoid mold spores but if you keep your house cleaned regularly inside and out it will definitely aid in preventing mold and mildew growth in the future.
Founder & Editor-in-Chief
I love old houses, working with my hands, and teaching others the excitment of doing it yourself! Everything is teachable if you only give it the chance.
I, too, live in the Pacific Northwest. I have one small aluminum window in my 1925 house. (Hate that thing. Plans to change it.) It used to get black mold. Tried everything. Still came back. Until, I cleaned it up. wiped the frame down with Tea Tree oil, leaving a thin covering of oil behind. And it’s been several years now and no black mold. I’m so grateful to the pioneers who are blazing this trail of reclaiming old windows and are freely sharing their knowledge with us. I’m on my fifth (ready for primer!) and sixth (just removed from the wall) sadly neglected window. Have 5 more to go. I keep thinking I’ve done the worst of them, until I get into the next one. It’s a challenge. The hardest part is getting them out of the wall to work on them. And, when I’m not hating it, I’m loving the challenge. I love seeing the beauty come through.
I have question, I have some artificial flowers of all
Types and sizes in my backyard and since they were left
Out there this past winter, now that it’s summer and I went to
Change them out I’ve noticed little.black mold/mildew that are visibly on the petals ect. What is your advice in this situation?
Thanks!
Great information! Can vinegar be substituted for bleach? I’ve read (cannot remember where) that vinegar molecules are smaller than those of bleach so soaks deeper into wood and kills mold like bleach. I’m trying to save my dining room floor. I’ll be asking someone to check joists and subfloor in the crawl space.
I’ve used a 50/50 vinegar solution to clean up a major mildew issue we had this last spring due to an insane amount of rain we had over most of the winter and early spring. It works to clean, and kill, but doesn’t prevent from what I can see. We had the same issues pop up a few weeks later, with patches growing in the same corners and blooms on some antique furniture (where I personally think it all started from). I bought some new stuff but haven’t tried it yet, although I’ve used mold inhibitor primer from the Zinsser company and it worked great.
Hey Scott! I am a single mom, just bought a 70 yr old house. I know nothing about older homes and I’m trying to learn all the how/why/what about fixing it up. All of it intrigues me. And your blog has been such a valuable resource. Thank you!
My home is half basement half crawl space. I’m still needing to encapsulate the crawl space (major moisture issues) but there are several joist surfaces in the basement with significant mildew or mold. As in, I’m going to have to probably scrape it off with a taping knife.
There is a small entrance from basement to crawl space that isn’t yet fully closed up.
Is it pointless to try to remove the issue in the basement if the crawl space is in need of treatment and I can’t yet fully separate the two spaces?
If you scrape it, wear a respirator and glasses that seal against your face. I’d so allergic to this stuff that I would die if I tried to do what you are talking about. You need to talk to an expert about the moisture problem. Maybe you need vents or plastic on the ground. When you bought it, did you have it inspected? Back to the scraping the mold, that thought terrifies me. Spray it with bleach first. Get a hazmat suit and bleach the hell out of it first.
I live on the coast in the Pacific Northwest where it is very humid and battle mold on a regular basis. I have tried many things but my favorite (and I think best) is Lysol disinfectant. I get the concentrate in the brown bottle and mix it at double the disinfectant rate, then wipe down wood furniture and even leather with it. The mold is slower to come back than with bleach or other solutions I have used. The only drawback is the strong smell but will dissipate in a day or two. It has not adversely affected any of my antique wood furniture. It’s my go-to now!
Hi Ruth Ann,
Love it! We love when our friends and followers share their tips and experiences on the blog!
Best of luck to you in all of your home DIYs!
-Alyssa at The Craftsman Blog
Thanks for addressing this topic. What is the remedy if the item cannot be washed or wet very much? I have 2 rattan (cane?) chairs in the basement that I use for extra seating. I will need to get them cleaned up before using them at Thanksgiving, so your idea will be very helpful. Thanks.
Tough to clean if you can’t wet it with the bleach solution. Cane chains can get wet then dried off immediately. Should work well.