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Solving a Crawl Space Water Mystery

Crawl Space Encapsulation Moisture Problem Mystery Gutter Downspout 1

When I started Energy Vanguard in 2008, I didn’t know how it would evolve and had thought early on that I may get back into home performance contracting. I did a couple of jobs, the last one being a crawl space encapsulation for my friends Tony and Gabriella. They had a house over a moldy crawl space, and Gabriella had developed a cough since moving in. When I inspected the crawl space, it seemed an excellent candidate for encapsulation, but on the day I arrived to start the work, I discovered a water mystery that I had to solve first.

The photo above shows a shot of the crawl space. The back corner on the right side was dry when I had done my inspection, but on the day I arrived to start sealing it up, that corner was full of water. It was raining pretty hard outside and had been all night.

With standing water in the crawl space, I couldn’t begin work. You never want to encapsulate a crawl space if there’s a bulk water problem because water under the plastic will find ways to get on top of the plastic. It’s meant as a vapor barrier, not a liquid barrier. Ideally, you get rid of the water by stopping it from coming into the crawl space. If you can’t do that, you need a drainage system and perhaps a sump pump to handle it.

So, we started searching for the source of the crawl space water. My first target was the outside of the foundation wall right there where I discovered the water. It was on the right side of the house. I went outside, dug down into the dirt there, and found that it was dry. The water definitely was not coming through there. Where the heck was it coming from?

crawl space encapsulation moisture problem mystery gutter downspout 6

We walked around the house looking at everything. In the front was the large camellia bush you see below. If you look closely at the photo, you’ll see the culprit. You also can see that it was still raining pretty hard when when I was doing my detective work.

crawl space encapsulation moisture problem mystery gutter downspout 3

Behind the camellia bush was a downspout. The downspout came down to a small strip of soil between the house and where the driveway stopped. Someone in the past had connected a downspout extender but it had come loose, so most of the water was dumping right there in that little strip of soil next to the house. And that strip of soil was dripping with water.

crawl space encapsulation moisture problem mystery gutter downspout 4

The really interesting thing here was that part of the house was on a slab. My sketch of the floor plan below shows the layout.

crawl space encapsulation water mystery floor plan detective

The water was traveling under the slab to get back into the crawl space! The driveway actually had a lot of slope down to the street, but in this case the water—or at least enough of it to cause a problem—found an easier path to the crawl space.

We reattached the downspout extender, and I made sure to screw it securely to the downspout this time. The corner dried out. We finished encapsulating the crawl space. The indoor air quality improved. And Gabriella breathed easier.


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This Post Has 5 Comments

  1. Smart stuff water! We think
    Smart stuff water! We think tracking it’s source should be easy. “Water runs downhill” after all. But; “downhill” means path of least resistance, and it’s often a challenge to identify the pressure source, because that piece can be hidden from sight. Ever seen an artesian well in the middle of a flat field? Or popping up under a house? 
    Please emphasis the point that you investigated to find the cause, then resolved, and verified the result did indeed solve the problem, BEFORE continueing with the original project. 
    How many times have we visited a home, where a contractor (sometimes several) have already “fixed” the problem. In reality, they attemoted to bandaide the symptom, and may have made the problem worse.

  2. Seems that 90-plus percent of
    Seems that 90-plus percent of the time the homeowner is battling water intrusion into the basement, crawl, or downstairs room…it’s no more than a gutter, downspout, drain, or surface grade-adjust issue. The rush to bring in the backhoe for expensive foundation wall treatments and french-draining appears to be an over-used recommendation. Checking, cleaning, and adjusting existing systems reveals so many helpful answers and saves the homeowner so many dollars on “unnecessary surgery”.

  3. I found an interesting water
    I found an interesting water intrusion not long ago involving the masonry weep holes which were actually below ground level. These fill the space between the brick and the foundation to the point that water flowed in a small stream into the crawl space at the door. 
    The same home had a large flower bed which ran along the garage walls, bordered by the sidewalk which had the neatest little brick dam. this held the water during moderate to heavy rain and actually spilled it through a foundation vent which the  
    builder had filled the front soil levels to just a couple of inches below. In that case, a drain had to be installed going under the sidewalk to a safe and lower location for dumping that water.

  4. Any of you guys have any
    Any of you guys have any recommendations as to how to keep fumes from getting into a home from a crawl space.  
    Obviously seal the gaps in the floor, but any other ideas such as specific fans or radon mitigation devices? Anyone ever work on such an issue?  
    The reason I ask is because yesterday I did air quality testing at a home and discovered an unusual chemical odor in the crawl space, and the same odor in the home. I think it was automobile gas related. Once before I found a similar odor in a crawl space and home and testing revealed it to be high levels of auto gas. Someone likely put it in the crawl space years ago to kill bugs, at least that it what an exterminator told me people used to do here in Florida.  

  5. My crawl space is wet. There
    My crawl space is wet. There is standing water. Ppes to hot water heater came apart. Front yard is higher thsn house. How do I direct water away from my house?

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