Crawl space mold removal techniques

[Moukie]

Hello,
I own a home in SC that had mold present on the crawl space floor joists when i bought it 7 years ago. I put down a vapor barrier, which, along with vent maintenance, seemed to keep it at bay. Well, 2020 came and i did not open the vents like i should have, and i now seem to have more mold than i used to. As expected, humidity was high, ducts were dripping, etc. Well, i addressed this a few weeks ago by placing several fans in and opening both doors and all the vents. Mother Nature helped the most by providing 2+ weeks of low humidity.
I had a crawlspace company out Monday to check and they were not overly-excited. Said my level of mold is "expected", and they gave me an encapsulation quote, but said what i have done in last 2 weeks is good and to monitor conditions for a while. I have already replaced 11 of the 16 vents with temperature-controlled ones, and added a Tjernlund humidistat and temperature controlled 220cfm fan in one vent hole. My moisture level when they checked was <50% RH, and 16% in the joists, which he said was good.
I wish to take this further, and remove the mold. I bought a professional fogger and 2 gallons of the Concrobium. I fogged one gallon Monday. Not sure if it really helps, but it makes me feel better. I have also been wiping the mold off the joists with a vinegar-soaked rag. This is killing my shoulders, and at current pace, will take me most of the Winter. I am also finding that i smear some of the mold with this technique; making the joists appear dirtier than when i started.
I am curious........as i assume my mold is now "dormant", is it acceptable to leave my Shop vac outside the crawl space and run a long hose in through a vent and suck the mold off the joists? I would use a brush attached to the hose, and would wear my cartridge style ventilator mask while vacuuming. I know the objective is to not send airborne any more spores; hence the wiping with a wet cloth. Should i really be concerned if i suck the spores off with a high power shop vac and let them out in the front or back yard? Once finished with the job, i would again fog the area with Concrobium.
Doing it this way would also enable me to clean up some of the low hanging dirty insulation, and some of the mouse nests that have accumulated over 30 years. I think this will speed up my progress 10X, and my thought is that it will also be more effective; especially with the new air controls in place and the Concrobium afterward.
Ultimately, i think i will fully encapsulate, but i cannot do it for a few years as this is not my primary residence.

Thoughts/suggestions are much appreciated.

David in SC

 

[joecaption]

Buy some Bora-Care with Mold care and just spray it on with a pump sprayer and forget about it.
Google it.

 

[slownsteady]

I've heard good things about the Concrobium fogger combination. It is supposed to actually kill mold spores. I don't think I would be too worried about staining as long as the mold spores are dead. No expert here, but the Shopvac plan sounds OK.

 

[Jeff Handy]

Get a dehumidifier in there.

You can run the output to a condensate pump, like for a furnace.
Pump it into an adjoining room with a drain.
Besides dehumidifying, it also gives off heat, which cuts down on condensation on joists and ductwork.
Run a fan down there, even in winter.
Just a decent box fan on low speed is enough, to keep the air moving a little.

After your vac cleanup, you can paint all the wood framing with Kilz mold killing primer.
There also might be specific paints made to cover and prevent mold.

 

[Moukie]

Thank you for your input. I mainly want to protect going forward, until i have time to do the full encapsulation. Cosmetics is important to me as well; hence the desire to remove mold which is already present. There is always a chance i will sell this place, so i want the crawl space to be nice and clean for the next owner. Funny, i have thought seriously about removing insulation and painting the entire wood system with a bright white mold-resistant primer when i do full encapsulation. I love being able to see, and bright white makes it so much easier and nicer looking. My family thinks i am crazy!

 

[Jeff Handy]

Bleach and water mix, or a commercial cleaner such as for roof mold, could be used to scrub down all the areas that look dark or stained.
If you are getting sore, just do a small section at a time til it’s knocked out.

I have used Concrobium many times, but never with the fogger.
I have clients who had their attic fogged with it, followed by mold killing paint after it dried, and they report very good results.
The wife had been getting asthma attacks which are now gone.

You can also apply Concrobium with a garden sprayer.

 

[slownsteady]

You can search Concrobium on this website. I know of at least one thread on the subject that has a recipe for a homemade Concrobium knock-off.

The fogger has the advantage of getting into hidden spaces.

 

[Spicoli43]

I had a small mold problem when I moved in this house in Montana, and cleaned it up with Peroxide. As far as using a shop vac, what about the exhaust? When I vacuum up sawdust, I smell a little release of sawdust particles that get past the filter. Mold spores of course are very tiny, and might completely bypass your shop vac filter.

 

[Moukie]

Thanks all for the advice. I was actually planning to leave shop vac outside without a filter in it, run a long hose in through a crawl space vent, and exhaust all i remove directly into the backyard. Would this be viewed as irresponsible? No way do i want to spread the spores in the crawlspace; nor do i want to inhale them. I would not assume they could do much harm in the backyard, but i may be wrong. I plan to have a cartridge style mask on the whole time. When done, i can do a super cleaning of my shop vac.

Thoughts.

 

[Jeff Handy]

No problem leaking some spores outside, they are everywhere outside anyway.

 

[68bucks]

I had an attic mold problem. I used about a 15% bleach solution to clean it. I based that on a couple of products intended for that purpose. Researched and that is all they were really. I bought liquid pool chlorine, which is just bleach and diluted it in a pump sprayer. The results were pretty good and almost instant. You could test an area.

 

[Sparky617]

Bleach and water mix, or a commercial cleaner such as for roof mold, could be used to scrub down all the areas that look dark or stained.
If you are getting sore, just do a small section at a time til it’s knocked out.

I have used Concrobium many times, but never with the fogger.
I have clients who had their attic fogged with it, followed by mold killing paint after it dried, and they report very good results.
The wife had been getting asthma attacks which are now gone.

You can also apply Concrobium with a garden sprayer.

If you're going to make your own bleach/water combo add a couple of drops of dish detergent to each gallon of water. This acts as a surfactant and helps the bleach water stay on the joists longer to do its magic. We do this when we spray houses that have been flooded before we start the rebuilding process.

 

[ckev70]

Moukie,
Curious on they type of fogger you used. My parents house has moisture issue in a crawlspace trying to figure out how to best fog the space. Access is limited.

 

[Jeff Handy]

Home Depot rents a fogger just for Concrobium.
You point it towards one corner of a room at a time and fog each quadrant separately.
But no point in fogging that crawlspace until you get it dried out.

 

[ckev70]

Home Depot rents a fogger just for Concrobium.
You point it towards one corner of a room at a time and fog each quadrant separately.
But no point in fogging that crawlspace until you get it dried out.

Will add a crawlspace vent fan to help dry it out to start. I'll have to pick a moisture reader and investigate crawl space humidifiers.

 

[Moukie]

Agree, i went to Home Depot to look at their Concrobium fogger and then found one on Craigslist for $120. Same thing. I think it is called a triple-jet cold ulv fogger? Ultra-low volume. Plan to spend $300+ if you buy one new.

Hope it works well for you.

Thank you to all for the feedback.
David

 

[soparklion11]

I have a small area of grey-white mold on the sheathing boards of my attic. I fixed my moisture issue and sprayed it with a homemade concrobium mixture (TSP, Sodium carbonate, borax). Its been dry for over a year. The mold looks dead but you can still see some of the grey-white frost. How do I remove the mold remnants? I'm considering sealing myself into my attic with PPE and respirator, then dry brushing it away - possibly with a brush attachment on a drill. The boards aren't smooth, which complicates the situation somewhat.... I'm also considering retreating with the same concrobium solution when it warms up again (Pennsylvania, December). Much of the mold is at the eaves and they are difficult to access. I've already fallen through a ceiling once. This isn't my attic, but in the bad parts, mine looked like the left half of the middle board on the left... so less than 50% affected before treatment. Now those areas are less bright but there is still a chalky grey remnant.

Should I spray with a mold primer? I feel like that any moisture that would enter the wood would be stuck in the wood if one side was sealed.