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The Mystery House Flooding Issue

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After we moved into the 217 Yale house (Oct 2021), the bay area started getting its first serious rains in many years, and our house started randomly flooding.

This is completely distinct from the very bad flooding due to stuff getting left in the sink that the washing machine drained into, which sucked but was not mysterious at all. šŸ˜„

This happened basically every time there was serious rain, which pointed immediately at the pipe that takes rainwater off the roof and through our house. Which is obviously bonkers, but youā€™ll see what they did here in a minute.

We donā€™t have pictures or video of when it got bad, because we were busy freaking out and trying to manage the water, but it got much, much worse than any of these videos show. At its worse, the water was coming in fast enough to be visibly rising.

Hereā€™s some videos of the house layout, because none of this will make any sense if you donā€™t see why the rain on my roof goes through the inside of my house.

And hereā€™s some videos of the flooding itself.

More flood stuff:

Hereā€™s the video from when my sensors under the stairs first went off; no water in the entryway yet

Hereā€™s the entryway, about 5 minutes later

Not shown in any of these is that there was also flooding in the bathroom, which is to the left in the first (under the stairs) video; the entryway is to the right.

Hereā€™s under the stairs some time later, maybe 30 minutes

And hereā€™s the entryway around that same time:

entryway flood

An issue that I believed to be separate was an irregular bad/rotten smell in the downstairs bathroom. It was, it turns out, not separate.

We had several plumbers and a general contractor try to figure this out. No-one did. Special mention to the contractor that was sure they fixed it and yelled at me when I proved them wrong.

We have a video of a pipe inspection of the pipe leading out of my bathroom, and they definitely saw some problems, but nothing that looked bad enough to make them be like ā€œyou need to open up this concreteā€. And, of course, we didnā€™t want to open up the concrete if we could avoid it, but also by the time they found the problem spots they were far away from the place where the water was actually showing up in the house.

It turns out that was the problem spot, and the water was travelling a long way before it came out, as youā€™ll see.

A side effect of all that investigation was that I now had access to the area under the stairs, and eventually I tried recording video under there. I also tried running the water for a long time. This turned out to be enough to actually show the issue. Fun part of this video: watch for the fleeing bugs.

Itā€™s worth noting there that my entire house is on a concrete slab with no basement or crawl space or anything.

The date of that video was 6 Feb 2024; everything else here occurred between then and mid-April or so.

Having seen direct evidence that the water was coming from under the concrete slab, and called up the plumber that I liked best of the plumbers that had tried to solve this problem, and told him I didnā€™t care how much it cost, it was time to open the concrete. Weā€™ll call the plumber SM. He told me to find someone else to demo the stairs if I ever wanted them to be put back, which is when I got my handywoman, weā€™ll call her LH, involved.

Spoiler: SM basically lived at my house for the next month and a half, and LH for much longer than that.

Once LH had opened up the stairs:

the stairs opened to reveal the concrete

, SM and his crew got to work with jackhammers:

the stairs after jackhammering

Fun fact: when you have people jackhammering concrete in your house for weeks on end, everything gets dusty to a level that is almost unbelievable:

Once they got that far, they started running water down the rain pipe, and the problem showed up almost instantly:

water test water test with the direction the water came from circled

Unfortunately, it showed up in a way that made it clear that we hadnā€™t found the actual problem yet, so the kept cutting concrete to follow the pipe. Once we got to the Harry Potter room (the room under the stairs), they had to pool flooring, and it became clear there was a problem:

mold in the Harry Potter room

That black stuff is all mold šŸ˜±.

And hereā€™s the video of what they found when they opened up that concrete:

We lucked out with the exact position of the hole in the pipe. There was all sorts of bullshit happening in the pipes under the stairs and the HP room, but of course most stuff would come out the largest hole, which was right under the HP room. It turns out that both walls of the HP room are foundational, load-bearing walls, which means they have concrete that goes down 2-3 feet further than the slab. This put a hard limit on where the water could go, and it never got so bad, as far as we can tell, that the mud got under the load-bearing walls. This means the HP room and a bit of the space under the stairs is where all the mud was; it did not spread any significant distance.

This meant that it was OK to just fill the space and pour concrete over it; nothing structural was impacted by the giant mud pit.

They eventually removed six full garbage bags of disgusting wet dirt.

The smell in the downstairs during this time period (about a week) was overpowering.

Somewhere around here I called our insurance company. It turns out that because the water was in our pipes, rather than coming in from outside in the usual way, it was covered, and we actually got a payout for about half the (extremely expensive) work! The insurance agent was amazing. It was Travelers, FWIW.

Moving on.

To get to the other end of the rain/kitchen sink pipe so they could replace everything, they had to dig all the way into the play space (downstairs living room), which involved some dirt.

dirt in the garage

And thatā€™s where we found the first real problem: there was a hole the size of a small childā€™s fist in one of the pipes, and thatā€™s how water was getting under the concrete.

It turns out that point was also the point where the kitchen water joined the rest of the pipes, and apparently kitchen grease rotting is very very bad for your pipes.

The red circle is the hole in question, because itā€™s not obvious from the picture. The rest is just general pictures of how full or broken the pipes were.

first set of bad pipes 1/6 first set of bad pipes 2/6 first set of bad pipes 3/6 first set of bad pipes 4/6 first set of bad pipes 5/6 first set of bad pipes 6/5

A pic of the shiny new replacement pipe:

shiny new replacement pipe

It didnā€™t stop there, though. I was not interested in having to do this twice, so I insisted that we check all the connected pipes. Next stop was the pipe heading to the street/sewer.

diggy diggy hole

We stopped to review the entire plumbing layout and the work so far, just so that Iā€™d have video of how the plumbing under the concrete works:

Once weā€™d put concrete back in the garage:

F hand print in concrete K hand print in concrete

, it was time to head towards the remaining pipes, the ones leading to the back yard and the downstairs bathroom:

play space ready play space more ready play space big cut

The pipes there we no good, too.

second set of bad pipes 1/2 second set of bad pipes 2/2

The pipes in my bathroom were also terrible.

bathroom 1/5 bathroom 2/5 bathroom 3/5 bathroom 4/5 bathroom 5/5

The tile got put back much later.

From there we headed towards the back yard. The pipes were also not great. SM said they could last another 10 years. I said rip them out; I donā€™t want to do this again in 10 years.

laundry room 1/3 laundry room 2/3 laundry room 3/3

Itā€™s also worth noting that several of the pipes were incorrectly sloped, allowing water to pool and corrode them from the inside.

In the end, the only pipes under the concrete that we didnā€™t replace were the bits of pipe for each fixture in the downstairs bathroom, about 6 feet of pipe at the back of the house with no known use at all (might be vent pipe, in which case it doesnā€™t need replacing, might just be unused), and about 3 feet of pipe leading to the upstairs bathrooms.

Thatā€™s it.

While we were doing all that, the roof in the lightwell was also known to be bad and needed replacing. It turned out to be way worse than anyone thought and they had to replace most of the wood, too.

This is also how we found out that there was no insulation on one wall of Kā€™s room. šŸ˜‘

roof 1/4 roof 2/4 roof 3/4 roof 4/4

Once all the pipes were replaced, we had to investigate the mold problem. We knew that there had been substantial mold; hereā€™s some more pictures.

mold 1/3 mold 2/3 mold 3/3

And some evidence of bugs, too, but no actual bugs.

bugs 1/3 bugs 2/3

The circled bit here is tile under the floor that was substantially wet once we took up the flooring. LH had to remove that and more, lots of tile was removed.

wet tiles

Se we had a mold person in to test the air. This went very badly; they found substantial amounts of Stachybotrys chartarum, AKA black mold. You know, the bad stuff. Panic ensued.

The remediators wanted me to remove everything in the relevant rooms, which I refused to do, which led to further discussion.

Once Iā€™d moved some things for the mold person to look at, her and the remediators and I were all very confused because thereā€™s no signs of water damage in the walls, no mold smells, etc.

And then she was like ā€œhey umm if they took up all the pipes, they would have had to disturb the dirt, right?ā€, because apparently that kind of mold lives in dirt, and we never really aired the place out between the pictures above and when the mold person came.

ā€œā€¦ Yeah, umm, there was some dirt, yesā€.

So I got an extremely large and expensive HEPA filter and a mold fogger and did DIY remediation based on the assumption that we didnā€™t, in fact, still have a serious mold problem, just a bunch of air that needed purifying.

We eventually got back a good mold readings, and proceeded to start putting everything back together, which is when LH basically moved in. Cutting up moldy walls, replacing them, putting floors back, buying new floors, tiles, moving furniture, so much stuff. As of this writing (15 Aug 2024), weā€™re not quite done, thereā€™s some tiny stuff to do, but we should be done next week or so.