How to prevent mold growth under weight mats
Hey all!
I'm currently cleaning out the basement and rearranging some things after my brother in law has moved out. He spent the better part of every afternoon down here working out and (I'm assuming) sweating (figuratively) gallons. I pulled the mats up to move em around and was hit with a deep earthy smell which made me IMMEDIATELY panic. There was only one super dark spot which was immediately washed off with warm soapy water and steel wool. There are other places that don't look too bad, but I am seeing markings on the floor elsewhere that match the pattern of the interlocking mat.
I'd like to keep working out down here, but I'd also like to not cause mold problems in my own house. Can anyone think of a way to essentially insulate the mat from the cement floor without creating a different problem where the plastic bottom ALSO creates an environment for the mold to grow? It's also possible that I'm WAY blowing this out of proportion...
I'll include pics on a follow up post
You could put a plastic barrier down between the puzzle mat and the concrete. If the moisture is on top of that barrier, then you shouldn't get mould underneath, just on top.
I think the big thing to consider is airflow. Do you run that fan for a significant amount of time to allow for drying after using the area? We used to have a similar setup in our old house, and we never had an issue like this, but we had really good airflow in the area that had the interlocking foam tiles. We also would take them up and scrub them twice a year, but we never found any mould while we were doing so.
Is the moisture definitely just from sweat? You could probably put down towels on top during workouts to help prevent he issue as well.
It's the first time the fan's been down there as far as I'm aware, wasn't his house so I'm sure he didn't think about needing anything like that. I do have a dehumidifier near the door, but that's been unplugged for a little bit because of reasons I'm not aware of. I've plugged it back in and will turn it on once I finish airing all that out.
I have some plastic sheeting I can place down but was worried if some moisture does make its way between it would essentially be stuck there and make mold grow faster.
I do believe it's just from sweat. Seems like I'll have to pull up the tiles more often than I have been to keep them clean.
Thanks for the response!
I'm wondering if there was a spill or something and it wasn't just sweat? I get pretty sweaty and even when I was doing sit-ups (ie laying directly on the mat), I didn't sweat enough to soak through like that. I would also expect the sweat to be more spread out?
I think if you put down the sheeting correctly, then it would actually just fix the problem completely, but you do want to make sure that you place it with some overlap so that the liquid won't get through. That said, if this were me, I wouldn't put down any other barriers, but I would keep an eye on it over some period of time to see if the sweat issue continues, or if this was a one-time issue. To me that looks more like a water bottle spill or something and not just a sweat mark.
Not to beat a dead horse but I just came back down after letting the fan run, and the squiggly lines have gotten much more defined, and white. I'm back to thinking it was somehow some sweat getting through and the white is the moisture drying up and leaving the salt behind. Which sounds CRAZY but I don't think mold would turn white?
https://ibb.co/hRMYQjsF
https://ibb.co/VYcL8mpR
(I'm not aphoenix :3 sorry to butt in)
That imo looks like efflorescence, either from human-salt or otherwise! Could always be the case that a bit of moisture consistently pouring into that area was enough to help drive it out of the concrete, which I'm also assuming is unsealed.
YES that's exactly what it looks like it is. I should have read all the comments before reanswering.
Though I didn't realize that it was often salt being pulled out of the concrete and not salts or sugars that were introduced. I learned something!
Hah, no worries; I spend too much time on building youtube -- this is far from common knowledge đ ď¸ and to be fair it could easily be a bit of both!
If thatâs what it is, hydrochloric/muriatic acid will get it out. They sell cleaners specifically for that, but youâd want some PPE and good ventilation to use anything like that.
Not sure itâs worth that kind of trouble since itâs covered, anyway.
Hmmm, it shouldn't look worse over time, that's strange. I think you might want to look into a waterproof concrete sealant because it looks like that stain is leacging into the concrete. It doesn't actually look like mould to me though, it looks like something crystalline. I do think it more likely to be a spill; either Gatorade or soda?
Either way, I would consider sealing the floor better, then watch where the moisture comes from and keep a fan there to help moisture evaporate without pooling, be it sweat or otherwise.
I'm not so sure that's mold. It might just be water staining. Of course there's no way for me to tell from the pictures. If you think it might be mold you should definitely disinfect it well before you put anything back down.
I was raised in the "bleach kills everything" school of thought*, so that's what I would use. Dilute one part bleach to nine parts water and then soak the concrete, give it a good scrub, and let it dry. Make sure the area is well ventilated and you aren't bleaching anything metal, or mixing bleach and ammonia cleaners.
You should also disinfect the mats. If you use bleach, test it to make sure it doesn't destroy the rubber.
A little Googling suggests that vinegar undiluted might also be a good option and less caustic.
* My dad is a veterinarian. He got something biological on him in a class once in vet school, and the instructor said, "Put bleach on it."
"What if that doesn't kill it?"
"Put more bleach on it."
Good call to ask and check! That said, please bear in mind that mold requires food, moisture, and warmth to grow -- even if that were mold, and it were stuck under the mat, it'd be missing food and wouldn't be an issue. At a complete guess, the awful smell is just some bacteria growing off of the ... liquids that would seep down between the mats.
That said, a couple thoughts!
Those look like they are almost definitely from spilled liquid. I would say, if you spill liquid immediately pull up the mats and wash/dry them, and you wonât have an issue. And maybe clean once a year â in the gym I train at we have 20 people in there soaking the mats in sweat like a slip and slide, and itâs fine. We do spray and mop the top layer after every class, and pull it all apart annually to be sure.
Two images below, one of the now cleaned spot, and other of some small areas following the squiggle pattern of the interlocking mat. I'm thinking I'll need to wash and air those out as well.
EDIT: Added a high level view to show everything as well
https://ibb.co/YFdz5crN
https://ibb.co/CyvMTgP
https://ibb.co/HD3hHMQs
I don't think you're dealing with mold after looking at the pictures. Looks more like water staining to me. The squiggly lines also look man made, also like something had been glued there at some point. There's also a chance in a basement that the water stain is actually from the moist soil under the house. If the concrete was left more exposed it would normally be able to dry out, but in this case the mat was preventing it from staying dry, so worth keeping an eye on.
Concrete is porus and will dry out, it may just take a few weeks to dry out deeper in. If you're not spending as much time down there as your BIL did, it also won't retain as much moisture and humidity. If you live in a more humid climate it'll definitely take longer. Running a fan for a while after a workout will help circulate dry air near the concrete and help things dried out (doesn't need to be 24/7, and probably only if there was a really sweaty workout). And consider lift the mats up after a workout or propping something underneath when not in use to make sure it really dries out over the next couple months (probably not something you'll need to do forever).
To echo u/first-must-burn, wouldn't hurt to give it all a good bleach treatment just to freshen everything and make sure you give it time to fully dry before putting mats back.
I think the pattern matches the interlocking teeth of the rubber flooring, so probably some liquid running down between them. That would be consistent with what @aphoenix said about it being a spill.