The year 2013: Mold makes itself known
We needed to learn how to eliminate mold from our home’s subflooring this year. The flood waters caught us of guard early in the month of July, dumping more than five inches of rain one evening in an area (southern Cochise County, Arizona) that usually gets less than two inches of precipitation for the entire season.
As I’ve said before, it won’t happen again. We’ll be ready for it next time.
But it did happen this once, and yes, we did end up with some mold under the interlocking rubber flooring squares. Surging happily up from the bottom layer of black plastic, taking hold and growing in the cracks between OSB strand boards that serve as our flooring system’s subfloor, the fuzzy gray stuff with it’s darker “Uh-oh!” spots spread out in all directions.
Fortunately, although there were initially a few wet areas in nearly every room of the house, it wasn’t that bad. I’d gotten on it immediately. Where rubber was lifted away to expose damp wood, the strand board “breathed” itself dry without allowing mold to get a foothold.
Overall, after enough time had passed to get the full picture, it looked like a portion of Pam’s bedroom, most of the utility room, and a bit of my office would need to be treated for mold.
The rest of the house–including, surprisingly, some that had initially been the wettest–survived the flooding just fine.
Eventually, I got around to addressing the problem.
Amazingly, at nearly 70 years of age, this was the first time I’d ever needed to seriously consider how to deal with mold on any significant scale. Must have lived a sheltered life.
I was thinking Kilz brand primer, available at Home Depot, killed mold. But no. What it will do is prevent mold from forming on wood that’s been treated with Kilz, but it won’t kill a mold growth that’s already established.
Oh. Okay. I never liked working with Kilz anyway. That stuff sticks to your shoes until it’s covered with a coat of paint. Kill the Kilz idea.
What does kill mold both quickly and cheaply is plain old ordinary laundry bleach. That, and Lysol spray, but for treating sizeable areas of floor, bleach looked like the way to go.
I talked with several people who knew the drill, ranging from one of our neighbors who’s done a lot of mold killing to Pam’s son, Zach. Zach was once on a crew that had to de-mold an entire house. The various informants recommended anything from a 1:1 (50/50) bleach/water mix to 70% bleach, 30% water. Everyone warned against using full strength bleach right out of the jug and likewise let me know that anything below 1:1 would be ineffective.
The most logical mix (for me) was 2:1. It was within the “acceptable” range, but toward the high, strong end. It was easy to eyeball when pouring into a container.
Let’s do it.
Hm…not quite ready yet. “Everybody” says to use a sprayer to apply the bleach, but what works for “everybody” doesn’t always work best for me. The sprayer from Home Depot, recommended by an employee, turned out to have a line on the instruction sheet that read,
“Do not use with caustic cleaners such as bleach….”
Awesome. The sprayer looked like a bugger to assemble. I hadn’t wanted to use a sprayer, anyway.
I’d wanted to use an open container and a paint brush.
So that’s how we’re doing it.
With Pam’s bed and the necessary rubber floor tiles out of the way, it was a simple matter of brushing a “layer” of bleach water onto the wooden (OSB strand board) subflooring…and watching the magic happen.
It really is like magic. The instant a patch of mold feels the bleach-loaded brush swishing over its location, ye olde moldy disappears.
Just like that.
Watching mold meet its match under the ministrations of a bleach-powered paint brush was fascinating. Had I not needed to get out of there (due to the bleach fumes being in a bedroom with only one door and one functional window), I’d have been tempted to just hang out and stare for a while.
Beautiful. It was truly beautiful. We’d considered replacing some of the subflooring boards, but there was clearly no need to do so. One swish of bleach and they were like new…only better.
Now that it was evident a brush could be effectively used to apply bleach to mold, it was time to list the advantages of a brush over a sprayer:
1. No assembly. Paint brushes come already assembled, right from the store.
2. No overspray. When bleaching a large area such as an entire house, the sprayer wins the day because bleaching a whole house with a paint brush would take approximately…forever. But for smaller areas, or when doing a fraction of a room at a time, the brush is plenty fast enough–and it doesn’t “fumigate” places you don’t want bleach to fumigate.
3. Precision application. Using the brush, I was able to “paint” the bleach precisely where I wanted it, right down the line, with 1/4″ of margin for error being more than enough.
4. Simple or no cleanup. With a sprayer, the very least a user must do is rinse the entire assembly out thoroughly after each use. A paint brush doesn’t even have to be rinsed. It can be left to dry (atop a paint can, for example) “as is”.
5. Cheap. The sprayer cost something like thirty bucks. The paint brush was ten or less when new, and that was a while ago.
6. Small batches of bleach can be mixed up for brushing quite easily. I used a little plastic pot–probably a leftover planter from Colorado–that holds about a pint and a half batch without being full enough to risk spilling.
For the sprayer, then, there are two options: Either take it back to the store or stuff it into storage for a rainy day.
Bleaching the rubber floor tiles
Most likely, the average reader has never seen another flooring system like ours. Laid directly on the Earth, and all loose lay at that, the layers (from the bottom up) go like this:
1. One layer of 6 mil black plastic, a single piece underlying the rest of the floor for each room. Within the confines of a given room, there are no seams.
2. One layer of 15/32″ OSB strand board, with full size 4′ x 8′ pieces used wherever possible. Edge and/or corner pieces are the only ones cut to fit.
3. One layer of 36″ x 36″ interlocking rubber tiles. These are 3/8″ thick, manufactured from recycled tires, and extremely durable.
Zach (Pam’s son) offered to round up a few of his buddies to help replace our present system with a concrete pad, poured one room at a time by men in their twenties who have plenty of concrete pouring experience.
We thanked him…but no thanks. Four to six inches of concrete would permanently eliminate the potential for flooding during the annual monsoon rains, yes, but that’s the only advantage concrete would offer.
Disadvantages (all of which were considered before building as we did in 2010) would include:
1. Off gassing from concrete, especially a lot of it freshly poured, could be detrimental to Pam’s already fragile health.
2. Cost is not inconsequential.
3. Once “locked into concrete”, the Border Fort would be “stuck” to one system. There would be no further flexibility in the home.
4. Most of all, my wife falling on concrete would be a recipe for disaster (aka broken bones, possibly even a hip). She’s fallen many times on the rubber but has not broken a bone in a “home fall” since we built this place–which is some kind of personal record for her.
All right, then. This explains why we’ll be sticking to our movable flooring system. We’re keeping the rubber tiles.
We’re also cleaning and bleaching them (the ones that had to be removed to expose growths of mold). The rubber has shown no signs of mold growth. It appears that mold does not consider rubber to be a nice neighborhood in which to bring up children.
But it seemed wisest to scrub and then bleach the rubber anyway. If it turned lighter (which it did not, though the subflooring wood did), we didn’t care. Most of all, just in case rubber could be carrying a few renegade mold spores, we wanted to be sure those were all eliminated.
First, the half dozen tiles that came from Pam’s “bed corner” were pulled out of the “awaiting action” tile pile (which sits in my office at the moment). Wooden supports were arranged on the driveway gravel to keep the rubber off of the dirt and rocks and to allow air to travel beneath the tiles.
One by one, the tiles were (a) squirted with a garden hose, (b) scrubbed with a push broom, than (c) flipped over to be cleaned likewise on the other side.
With most of the obvious dirt and stray cat hair removed, each tile was then taken to a separate set of support boards where a layer of bleach water was applied with the paint brush.
After that, the tile was simply left to dry in the sun (on both sides, being flipped as needed), then tucked back into place in Pam’s room.
Wow, does that section ever look and smell clean now!
The following video goes through the process, just in case text and still photos aren’t enough.
Things looked a bit iffy by the time the camcorder came out, though. Moderate sunshine had morphed into moderately threatening clouds.
It ended up being more than close. The last tile to dry…didn’t quite make it. It got sprinkled upon. Had to be brought inside, toweled dry with half a dozen paper towels, then left to dry out all over again in the office.
Fortunately, the results were worth it, with one exception. The clean, bleach treated tiles make the other, untreated tiles look every bit as dirty as they really are. Pam took one look and protested mightily: How dare I mix clean and filthy like that?
A quick promise to sweep and vacuum the filthy tiles before putting her bed back in place (which will probably happen on Friday, two days from now, when she’ll be gone with Zach to see her telemed psychiatrist and I’ll have the place to myself for a bit) was enough to keep the peace.
Whew! That was close! Unhappy redheads are nothing to take lightly.
We have a fair amount of moldy floor yet to cover, but this was a great start. The fear of mold infiltration in the event of flooding had always been of concern, especially considering the fact that our home was built right down on (even partially in) the soil itself. Now we’ve weathered the worst the weather can throw at us, and it looks like we’re going to be okay.
Besides, a new skill has been mastered and another desert adventure brought to a successful conclusion at the Border Fort. The rest should be routine.
Best of all, excluding the cost of the sprayer we did not use, the cash out of pocket needed to handle the mold problem came to a total of $10 for five gallons of bleach.
Correction. We bought five gallons of bleach, but it’s looking like a gallon or so will take care of all the mold we have in the house. So…cash out of pocket for mold elimination = $2.
We can live with that.