Decks, Gazebos, Porches, Stoops & Mold


Article Summary: Dr. Shoemaker, the leading expert in Chronic Inflammatory Response Syndrome (CIRS) says that outdoor mold isn’t a problem for people that are no longer able to clear biotoxins produced by mold and bacteria. In this article, I discuss a recent experience that proves this wrong. While sunny myself outside one day, I unwittingly inhaled biotoxins from mold. It took days to clear the brain fog, anxiety, and fatigue that followed. With a little sleuthing and using microscopy, I was able to quickly find this mold source and determine if some of the mycotoxins that made me sick were also getting into my house. Read about this process, as well as, how I went about remediating this surprising toxic mold source. May 23, 2015 (updated April 18, 2016)


Sun & Vitamin D

Deck Mold - Overview

A couple weeks back, we had one of the first really warm and sunny days after a typical Wisconsin winter. It was so nice that my wife and I decided to strip down to our briefs and lay out on our southerly facing deck. Having been through two separate remediation projects (more in other articles), furniture is rather sparse in our home and non-existent on the deck. No problem; having lived in “third world” countries, it only took a second for my wife to toss me an old bathroom towel before we were heading out the door onto the deck.

It was beautiful outside. The grass was greening up nicely, white clouds against a blue sky wafted by overhead. The glorious sun warmed our bodies nicely. Having studied about Chronic Inflammatory Response Syndrome (CIRS), I knew that gut dysbiosis, resulting from low levels of a key hormone called Melanocyte-Stimulating Hormone (MSH), often meant vitamin D levels were low in those with CIRS. Since vitamin D is essential to keeping your immune system working, I was glad to be soaking up the sun as the sun’s rays trigger production of vitamin D in our skin. Awesome.

I don’t use sunscreen not only because I know that lotions get absorbed through the skin directly into the bloodstream, but also because many sunscreens actually block UV-B rays. It’s the UV-B rays that are needed to make vitamin D! Some manufacturers are waking up to this fact and now make blocks for the cancer causing UV-A rays instead. Nevertheless, I personally think it’s just better to limit exposures rather than slather a cream all over my body. Within moderation, the sun is very good for us.

When I can’t get enough sun, as is often the case where I live, I supplement with 10,000 IU of sublingual vitamin D drops. This is based upon testing. This level of supplementation brings my levels up to 60 ng/mL. Dr. Ackerley has commented that folks with CIRS typically need 5,000 IU. I like the sublingual drops because folks with gut issues aren’t as capable of absorbing nutrients that are swallowed. By holding the drops under my tongue, much of it is absorbed directly into the blood.

So there we were, laying out on our 5 years old deck soaking up the sun. It felt great. As we flipped from side to side in silence, I lightheartedly wondered if the next time I Google’d our property, I’d see the two of us scantily clad, laying out on our deck in the satellite images. It made me chuckle.

Moldy Deck & Stoop

Spore Trap Overview

Spore Trap Overview

After 30 minutes or so, I was off to do some errands in town. It wasn’t more than hour into my trip when I remember commenting to myself how messed up I felt. I was having a hard time concentrating, my mind was starting to bounce all over the place, and I felt disoriented. It lasted all day. Later that evening, I slept really poorly, sweat profusely, and had bad nightmares. By the time morning rolled around, I knew I’d just been seriously exposed to mold.

After five-plus years into this illness, you’d think I’d be better at recognizing the symptoms. It’s just that it was such a nice day and I really hadn’t deviated much from my usual patterns that it took a while for me to realize what’d happened. I started making a list. I’d eaten a couple different foods. Could they have been that moldy? It had rained the day before and I knew some mold counts would be higher. On the other hand, maybe it was a chemical exposure as I’ve found the symptoms are somewhat similar.

Deck Mold - Joists

And then it dawned on me, it must be the deck! This was really shocking to me because the deck has a southern exposure, uses a PVC railing system with composite decking boards and treated lumber framing below. Not only that, but it stands between 18” to several feet above graveled covered weed-mat as the ground slopes toward the front of the property. As such, it’s really well ventilated. How in the world could conditions be right for mold?

Sure it rains and we get plenty of damp weather. However, that deck bakes in the sun daily. Besides, according to Dr. Shoemaker, outdoor mold isn’t supposed to be toxic for the most part even for folks with CIRS. The argument is that because outdoor mold has to compete with all the other micro-flora along with struggling against the weather, it just doesn’t have the resources to produce many biotoxins. Well, I found out the hard way this isn’t always true.

Deck Mold - Railing

As soon as light broke the following morning, I was outside climbing under the deck. Sure I’d seen some specks of mold and a little green algae growing here and there on the white railing system. However, this is Wisconsin and after all, we do live in a woods. Everything has a little mold on it. It never bothered me that much before. I was surprised what I found.

On the sides of many of the 2×10 treated floor joists was a very light pattern of black colored mold covering about a 3”x6” area. This mold was directly below the cracks I’d intentionally left for drainage between the plastic/wood composite decking boards. Its color was light enough, and I was in the mindset that the deck should be relatively impervious to mold, that it’d gone unnoticed. The fact that my nose wasn’t more than 6” above these patches of mold meant I inhaled a lot of biotoxins. I’m still incredulously shaking my head that I could react that badly to seemingly small and innocuous looking bits of outdoor mold.

Deck Mold - Underside

If you’ve read some of my other articles, you know that I have taught myself how to recognize mold under a microscope and have equipment to take spore traps too. Given that I wanted to try and get a sense of how much of these toxins were getting into my house, I did a scraping that I placed on a microscope slide. I also pulled a 5-minute spore trap between 6-18” off the deck as I heavily walked around on it.

I was trying figure out two things. First, what kind of mold was it? Second, how much of a plume of spores was billowing up between the deck boards where they could contaminate clothing and be tracked into the house.

As an interesting aside, I’d had nightmares before when sleeping in the master bedroom directly adjacent to the deck. On occasion, I’d woken up thinking I had to tear the deck off the house because water must have gotten behind the main deck framing board that attaches to the house – the ledger board. However, being a former builder, I knew all about water management and had built in several layers of protection against just this sort of water intrusion. On top of that, if there is one thing I’ve learned about CIRS, it’s that your mind will come up with all sorts of wild conjecture. To counter this, you have to be methodical and logical to weed through the neurosis of a mind that knows it’s under attack but can’t figure out from where. Thank goodness God gave us reason.

So I’ve always dismissed the possibility that the deck could be the issue. It had expensive copper flashing on top of a heavy bitumen based waterproofing membrane to protect the ledger board connection. It got lots of sun and was well ventilated. It was made of plastics and treated lumber. Given this recent experience, what I’m also learning is to give a little more credence to gut feelings. Something felt wrong about the space between the house and the deck. I should have spent more time trying to look into this.

In the future I plan on marrying my intuition with critical thinking more so. For example, my gut feeling was that there may be something wrong in the area of the deck. Analytically, when this happens in the future, I should consider making a list from the most to least probable sources of mold and then start checking off the list. If I get to the end of the list and still haven’t found any problems, then maybe I need to give the situation more time to become clearer. Its gut feelings tempered with reason. Life is so multi-faceted and I’m so grateful to have recovered enough of my health to be in awe of its intricacies.

Deck Scraping

Deck Scraping

I’ve included two microscope images. The first is showing the scrapings I took right from the moldy floor joists. For the most part, the clumps you see are patches of Chaetomium spores along with a little debris and fungal hyphae. The Chaetomium spores are blue in color. This is because viable spores absorb the Lactophenol Cotton Blue dye I placed on the slide to enhance viewing. Although not in the picture, there are a few groupings of relatively benign Cladosporium here and there too – elongated spores with darkened ends. From the image, you can get a sense of the size and shape of the Chaetomium spores.

Compared to round and more translucent Aspergillus/Penicillium spores, Chaetomium spores are larger, lemon shaped and have pointy ends where they were attached. Chaetomium is commonly found on deteriorating wood and paper-like materials such as drywall that have been very wet. This organism emits a strong musty odor and produces mycotoxins. When it comes to CIRS, it doesn’t matter that much if we’re talking about Aspergillus, Penicillium, or Chaetomium because they’re all quite problematic. “Small and round will knock you down”.

Spore Trap

Spore Trap

In comparison to laboriously trying your best to indentify spores under a microscope, what’s cool about ERMI testing is that it operates on a DNA level. As such, it eliminates a lot of error that’s inevitable when viewing under the microscope. I’m only saying this in case you haven’t read the Mold Testing article where I discuss the pros and cons of various types of mold testing.

If you look at the second microscope image, your job is to count the number of those blue lemon shaped Chaetomium spores in the picture. Although there aren’t that many in the image, it only covers a very small portion of all the spore captured. I’d say there are about 50 in total. In addition there are all sorts of other rather harmless Ascospores and Alternaria mixed in with a good number of more problematic Fusarium and smaller Aspergillus/Penicillium spores. When you do the math, it turns out there were about 2,000 Chaetomium spores-per-cubic-meter of air. For those with CIRS, this is a very high count. I guess it’s no wonder I was flipping out for the next day until I treated with Cholestyramine (CSM) and anti-inflammatory supplements.

What I learned from all this is that decks, porches, stoops, and the like can be serious sources of hidden mold. Furthermore, these structures are the gateways into our homes. If your stoop is moldy, every time you enter the house, you’re tracking in biotoxins. If the wind is right, this amount could be significant. In fact, when I reflect on my recent HERTSMI-2 scores that were OK but still somewhat high, I suspect a good portion of those higher counts were a reflection of the moldy deck and front stoop – the entry to our house consists of several steps and a landing made of the same composite materials as the deck.

Clean Up & Prevention

Deck Mold - Sprayer

After I’d quantified the problem, it was time to go after the mold. I hired a local contractor to pressure wash the underside of the deck. We used a gasoline powered sprayer with a narrow fan pattern – makes a very strong stream of water. Even with this sprayer and tip, he had to take extra care to blast the mold clear.

Before we began, I closed all the windows and doors along with shutting off the heating/ventilation system. Most homes draw in fresh air when the HVAC blower is running. I also set up my 2,000 cfm ventilation fan outside in an attempt to constantly be blowing fresh air on the contractor as he worked. The contractor was fully clothed, wore glasses, ear muff, and the P100 carbon filter mask I gave him.

Deck Mold - Blower

It was quite a project. After about two hours crawling around under the deck, the contractor emerged soaking wet and freezing cold. He took off to warm up and grab a bite to eat. While he was gone, I worked for another 1.5 hours blasting the PVC railing system clean before passing the sprayer back to the returned worker. Being outside, I wore a my lighter duty Silicon Mask (has some plastic parts) with P100 2297 Carbon Filters. He worked another hour spraying the decking boards.

Later that day, I removed some of the composite lumber treads and riser boards on the front stoop steps in order to be able to pressure wash the structure below. Happily, the tread and riser boards were screwed down with FastenMaster Trio deck screws and could be removed without much fuss. By the time we finished, I was amazed how long it took to clean the deck, gazebo, and stoop even with that high-powered sprayer.

In order to minimize re-growth, we also treated these structures with Thieves cleaner. This was done in two steps. First, I mixed up a 5-gallon bucket of water mixed with Thieves cleaner at a ratio of 50:1. This solution was connected to a pick-up on the pressure washer. After blasting a portion of the deck clean, we would swab the tip to a low-pressure nozzle. When this nozzle is installed, solution from the bucket is mixed into the stream of water spraying out of the wand. My thinking was that even though the solution was quite weak (as it was further diluted with the sprayer water), it would still help to minimize re-growth while the deck dried.

Deck Mold - Spraying

A day later when the deck had dried, we followed up with the second step. In this step, I mixed up water and Thieves cleaner at 30:1. My wife then sprayed this solution directly on every nook-and-cranny of the underside of the deck and gazebo using a 2-gallon lawn sprayer that you pump up by hand. I finished by spraying the railing and decking boards. By the way, have I mentioned that my wife is amazing? After traveling all week for her high-powered job, she crawls around under the deck over the weekend to spray Thieves solution so her husband doesn’t get sick. I’m humbled by her love.

I should mention that you need to be careful when spraying the decking boards. If you’re not careful, the deck will look very blotchy by the time you’re done. This is because the water can cut into wood and composite decking boards when using a narrow fan nozzle and a high-powered sprayer. The places it cuts deeply will be lighter in color.

Thieves & Sprayer

Unfortunately, you need to use a strong nozzle to knock off the mold in the gaps between the boards. As such, the solution is to keep the wand moving. In so doing, you get high pressure water into all the grooves long enough to blast off the mold without cutting into the boards.

To do this, use an arching motion back and forth like the pendulum on a clock. The spray starts about a foot off the deck on your far left pointing mostly sideways. You then swing the wand down in an arching motion wherein it’s only about 6” off the deck at its lowest point right in front of you. The motion finishes with the wand at the far right about a foot off the deck blasting mostly sideways. The total length of the arch is about three feet and the motion is completed in a couple of seconds. This motion is repeated over and over again as you transverse the deck. In this way, you’re blending in each successive pass with the previous one. Keep the wand moving quickly. It’s better to go over an area a few times and have it all blended in rather than making one cutting pass that leaves a blotchy finish that you can only remove by sanding the whole deck!

The first step to any remediation project is to contain the area, create negative pressure in the enclosure, and then safely remove the mold. Working outdoors, made this project much easier. Time will tell how good Thieves is at inhibiting mold growth. There is some evidence to suggest it’s good at killing mold and keeping it from coming back.

I remember reading a blurb about a woman that cleaned a portion of their moldy house siding with Thieves before her husband took over and finished the job with bleach. The area she cleaned remained mold free while the rest of the siding re-grew mold. That story always stuck in my head and for the time and effort that went into cleaning the deck, I figured $50 of Thieves cleaner was worth the expense just to see how well it worked. I’ll update this article in about a year and let you know how it turned out.

Update April 18, 2016

WhiteWash Supplies & Deck WhiteWash Supplies WhiteWashed Joists

Spraying a solution of Thieves and water on the deck framing did not work. We started to get mold regrowth by the end of the summer. We now whitewash the framing and this seems to be working well. To do this, we mix 2 cups of salt and 6-8 cups of hydrated lime in a gallon of water. This solution is sprayed onto the framing with a pump sprayer.

The salt helps the whitewash to stick to the wood. A large 40-pound bag of hydrated lime can be purchased at some big-box hardware stores. At 8 cups per gallon of water, the nozzle starts to plug up to the extent that you have to frequently bang the spray wand against the framing to keep the liquid flowing. It’s a bit of nuisance but I like the stronger mix. Make sure to wash out the sprayer tank, wand, line, and valve well after use.

Note: I plan on touching up the whitewash on a yearly basis. I’ve decided the next time we go to spray, I’m going to replace the pump sprayer hose with a 15-foot long braided line. This will allow one person to keep the sprayer pumped up and prevent the person spraying from having to drag the sprayer around while they’re under the deck.

Update End

So on top of a rather long checklist of maintenance items that I perform yearly to keep our home mold free, I’ve now added on deck and stoop inspection. Well, no one ever said life was going to be easy. I’m just glad I found this hidden source of mold and was able to clean it up relatively painlessly. The bright side is that I’m lucky my deck just happen to be higher up and consequently, that I’m able to get underneath it for inspection and cleaning without much trouble. Who knows; maybe now my ERMI scores will drop even lower. That would be another positive.

Take Away

Given what I’ve learned from this experience, I strongly recommend that those with CIRS avoid owning homes with decks, porches, and stoops. For those with UnderDeck Ceiling Systems, I cringe to think about what’s growing between the ceiling panels and decking boards. After having been through this experience, my advice for those with CIRS is to replace outdoor wood and composite lumber structures with masonry equivalents. If this just isn’t possible, plan on inspecting and cleaning these outdoor structures at least once a year.