When I asked what readers wanted more help with, the number one answer – by a long shot – was mold and mildew.
Unfortunately, when there is dampness and condensation, there is going to be mold and mildew. There is no way to completely prevent it. Products that say they’ll prevent it are thinking of typical “house” conditions, not boats. I hate to be the bearer of bad tidings, but you will have to clean mold and mildew every two to four weeks.
Prevention
Ventilation is the best preventative. Open hatches. Fans. Inside the boat, open lockers. PortVisors will allow you to keep ports open even if it’s raining. Use coupon code SmartBoatStuff10 for 10% off.
At the same time, try not to store anything fabric right against the hull – as condensation forms, the fabric will soak it up and get mildewy AND will just keep putting that moisture back into the air. Many cruisers raise the mattress above the hull by using interlocking rubber grids (Amazon) or the Froli System.
If you have shore power available, you can try running a dehumidifier but then you have to close the boat up so that you’re not just constantly bringing in more humid air. While we’ve never had the power that a dehumidifier would require, friends that I have talked to thought that it was not much more effective than ventilation unless the boat is in storage and no one is walking in/out or cooking.
Mold Killing Myths
Next, I want to play MythBuster for a minute: bleach does NOT kill mold or mildew. It can remove stains, but it does not kill the spores. Ditto for anything that bills itself as a mildew stain remover: it may remove stains but it does not solve the underlying problem.
More things that do not work to kill mold: any sort of wipes (as far as I know), soap, and Lysol – they can remove surface mold from hard surfaces, but won’t kill anything left behind.
Killing Mold – What Works
To kill the spores, you need one of four things:
- Vinegar
- Borax
- Concrobium (a commercial product usually found in the paint department, not with cleaning supplies; also available on Amazon)
- Very hot water or steam
Which one I use depends on what I’m cleaning.
Methods for Different Surfaces
Sorry, one method does not work for every situation. But here are my best methods for cleaning mold and mildew on different surfaces.
Hard Surfaces
For ceilings, floors, counters and the like: use straight white vinegar or a strong solution of borax in hot water. I may go over an area two or three times until my rag or paper towel isn’t getting anything more off. Don’t rinse – let the solution dry on the surface. I go back and forth on whether I think vinegar or borax does a better job.
Soft Surfaces
TO clean upholstery, fabric covered walls and ceilings, other things too large for a washing machine such as life jackets: straight white vinegar, a strong borax solution I use the hottest water I can stand, or a steam cleaner. If using vinegar or borax, rub it into the material and then blot it, let dry. This will usually take a lot of the black stain out too.
Washable Fabrics
In a hot water wash, use borax as a detergent boost at a laundromat or boiling in a strong borax solution in the galley. If borax is not available, use white vinegar. Rinse and dry.
Laundry, including sheets, towels, and clothing, is a real breeding ground for mold and mildew although it doesn’t always show up there first. Washing sheets and towels every week to 10 days can really help the situation. Use as hot water as you can and add borax to the detergent.
Paper Products
Paper items are a big problem as there is simply no good way to clean books and documents, yet they pick up mold fairly quickly. I have never found a good way to deal with it. The best thing is to keep books and papers away from the hull and where no drips are likely to fall on them.
The Bilge
If it’s possible to keep the bilges dry, it will really help. Otherwise, add a half gallon of vinegar to the bilge every week or so to kill anything growing there.
Lockers
Keeping the insides of lockers clean is an often-overlooked part of the fight against mold and mildew. I figured that Barefoot Gal had 41 lockers and drawers. If I made it a habit to empty and clean one a day, I’d get to them all in 6 weeks. While maybe that wasn’t as often as ideal, it’s a lot better than “only when I really saw a problem.”
Final Thoughts
Concrobium bills itself as a mold and mildew cleaner. I’ve tried using it on just about everything on the boat but I always felt that it didn’t do anything that vinegar or borax didn’t – other than let me spray it into areas that I couldn’t get to otherwise. I tried spraying many of those with vinegar and I think that Concrobium did do a better job. So yes, it’s part of the tool chest.
When I started cruising, I expected mold and mildew to be worst in hot weather. The reality is that winter is its peak season due to keeping hatches and ports closed and there being less heat to dry things out.
If keeping up with the mold and mildew is driving you nuts right now, just hang on . . . summer is coming!
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Van Den Broeck Rita says
special underlayer from “akwamat” there are 2 versions in it,rotfree,and not expensive
The Boat Galley says
More about our mattress topper: https://theboatgalley.com/sleeping-well-means-better-cruising/
Gina Soucheray says
We do, especially in cold water (Lake Superior) when body heat and cold boards meet theough the mattress. It can happen in warmer climes, too. We have done two things over time to create an air “gap” under the mattress. One is a layer of dri-lock tiles under the mattress. The other is a layer plasticized “horse hair” that one would get at an upholstery/fabric store. This is more flexible if you need to get to storage under the bunk. However, it can “shed” a little, somif you’re under that a lot, you’ll vacuum a bit! Either one works great for keeping the mattress dry.
Kelley Gudahl says
We use hypervent on Sailing Chance. It’s worked in both northern and warmer climates. And to be clear, we did get condensation this winter still but the hypervent kept it from touching the mattes which avoided ant mildew on the mattress.
Gloria Rooney says
We use hypervent and it solved our problem.
Joe Sprouse says
Defender has hyper vent also.
Tammi Abbey says
We have royal blue dodger, looks to be getting mold on the inside. Would concrobium work?
Carolyn Shearlock says
I don’t see why not — we use it on our hard dodger and it makes a big difference!
The Boat Galley says
Here’s Hypervent at Defender: http://www.defender.com/product3.jsp?path=-1%7C2276179%7C2276186&id=1818021
The Boat Galley says
We don’t really have a problem with it, I think that our mattress topper adds enough insulation that we don’t have the “warm body” problem causing condensation there. For those who do, Dri Dek can be used under a mattress to provide some air flow. You can get Dri Dek at West Marine, or a very similar product from Amazon: https://amzn.to/3ju6JTf
The Boat Galley says
Another good solution is the Froli Sleep System, which also allows air to circulate under the mattress: https://www.froli.com/shop/
Claire McCloskey Ford says
The Boat Galley, we used these on our 36, and they worked great!
tami says
an alternative to Hypervent, and what it actually is, is:
ENKAMAT is one name, there may be others. Search term “roofing underlayment ventilation”
I have used this as well. It’s super cheap, but it does eventually crush down although it still ventilated. Did shed some, but not too badly:
http://www.flandersfilters.com/wp-content/themes/flandersfilters.com/graphics/product_images/sm1006.jpg
Bazza says
Absolutely right Ann, it seems to be the only thing that works for us in tropical Australia. And your recipe is our recipe.
Bazza says
I forgot to add, we also use this at home. The timber walls in the house used to go black with mould in the wet season. We now spray the walls with the mixture at the beginning of the wet season i.e early November, let them soak it up for 5 – 10 minutes, then wipe with a damp cloth. Good bye mould.
Lynn says
We use a product called Homezone which we order online at http://www.homezone.com to prevent/kill mold while the boat is stored in Florida for the summer. It lasts for 6 months, we use the whole container placing paper plates all over the boat including the lazzerettes and engine room. When we return in the fall most of the odor is gone but we leave everything open for a couple of hours to be sure. The boat is as clean as we left it in the spring. This was recommended to us by another cruiser who has used it for several years…this will be our 3rd season. This is the last thing we do before locking the boat. Within a few hours the fumes are pretty toxic…its a form of formaldehyde. Use mask and gloves when handling.
Carolyn Shearlock says
I’ve heard good things about it, but if you use it while the boat is stored, you can’t have a boat watcher check the inside of the boat because of the fumes AND should not be used by anyone with breathing/lung problems.
Florian Wolf says
As we don’t like to use too many chemicals in our house and on our boat we solely use clove oil, even to ‘clean’ (aka ‘de-mould’) our leather upholsteries after the wet season – works like a treat, is absolutely non-toxic, smells nice and has been used by generations of Australians in hot, tropical conditions. Usage instructions are above, and see you later, mould.
Judy Cook says
I just found this product and used it on very dark black mold stains on the ‘monkey fur’ fabric under our windows. After a good dose, the stain practically disappeared!!! The powder was not particularly easy to use… even in hot water the crystals didn’t dissolve and clogged my sprayer. I soaked a sponge and used it to apply to the stains wetting thoroughly. The darkest stains required more than one application.
Carolyn Shearlock says
I’ve had other readers recommend using OxyClean (one said a tablespoon in a couple gallons of the hottest water you can still put your hands in) and a small scrub brush but I have NOT tried it. I’d suggest trying on a hidden place first to make sure it doesn’t change the color!!!
Carolyn Chancellor says
Thanks. I’ll try this and report back.
Michael says
We bought noodles to slide u see mattresses that allow air to circulate better. Yes, those pool toys!
Oliver Jane says
I was also impressed by how this product infiltrates into the source of the fungus to completely remove and prevent it from multiplying further. The only minor issue I found is the smell it produces when being used.