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Weird drain in floor of house I’m working on! Check out what’s inside of it…

A questioner said:
Weird drain in floor of house I’m working on

There is a hinged grate/lid with sheet metal pan and a drain in the laundry room of a house I am working on. The wood on top is pressure treated so I assume it’s intended to get wet. The drain is not connected to the septic nor does it have a trap; it drains out of the foundation under the back deck.

The elderly man that lived there passed away so I can’t ask him what the heck it’s for.There was a rug over it initially and no one knew it was there until we started demo and clearing out stuff. It is on the first floor, in the laundry room, connected to the garage.

We found the drain in the crawlspace and it appears to just go through the foundation wall under the back deck. The flooring around “the pit” is not waterproof and is regular pine flooring. It’s about 12” deep and the sheet metal pan is not heavy gauge. I wouldn’t trust it to support much weight at all.

r/whatisthisthing - Weird drain in floor of house I’m working on

r/whatisthisthing - Weird drain in floor of house I’m working on

r/whatisthisthing - Weird drain in floor of house I’m working on

Some of the answers were:

  1. Is it possible that room was originally not an (interior) room? Maybe a garage with a fake drain (just a hole through the slab) so water could get out?I could see doing something like this (even if it wasn’t due to some remodeling) if that area is treated as a mudroom. Coming in with muddy/snowy boots or back from swimming and dripping wet. Maybe even a place to hose off the dog.Edit: I missed the part about the sheet metal pan. That would make me think more along the lines of a mudroom, as opposed to a relic from a remodel.
  2. I could see a mud room feature. It’s a few steps up from the garage slab. The block foundation does not look like this was added later.
  3. I’m willing to bet the house used to have laundry tubs, rather than those newfangled machines.
  4. The house was built in 1983. Not outside the realm of possibility especially knowing that this was rural farming area up until about 20ish years ago.
  5. a drip pan for a drying rack, for sweaters and such. to keep the floor dry
  6. It’s just a drain for the room. My parents have this in their utility room. If the washer hose snaps or something overflows, it all just drains out instead of ruining everything.
  7. Looks concreted on all sides. Bugs may crawl up a drain if there is no P-trap, but any real drain will have one. If it’s a fake drain, then yeah, insects are a possibility, and I’d look to adding some protections (like a waterless trap seal/one-way drain valve).That being said, most homes are not insect proof anyway, and often have holes large enough for mice, squirrels, and even sometimes possums/raccoons to get in.
  8. Is the location near any mining?
    I’ve seen houses belonging to miners have a shower in the laundry, and accessible from outside.
    Out of the truck and straight into the shower, clothes in the machines.
  9. great idea! wood and wood floor. if its teak very nice. keep it there.
  10. No. the wood allows drainage so none is on the floor area at all. genius idea.
  11. I had a hardwood flooring specialist tell me to consider installing a drain next to my washer. When a plumbing or flood situation happens water has nowhere to go and will just ruin your hardwood floors.
  12. Back in a former life when I installed washer and dryers, it wasn’t uncommon for laundry rooms on upper floors to have a floor pan the washer sits in with a drain built in for that reason.Why you’d put the laundry room on the second or third floor is a question my back never got an answer for though.
  13. If I ever had a need for this, I’m getting a laundry elevator. By the time I’m wealthy enough to own a three-story house, and also too lazy to move laundry anymore, might as well put it down a chute, automate the washer/dryer with a 5$ arduino, and have it shove it back into the dumbwaiter, and send the finished laundry up.
  14. I lived in a 3 story townhouse with the bedrooms on the top floor. I’d rather haul a washer and dryer to the third floor once than infinite loads of laundry down to the basement and back up the the bedrooms.
  15. im guessing bedrooms are on the upper floors? no one likes carrying huge heavy baskets down a bunch of stairs
  16. Washer might of over ran once before. The rest of the floor is real hardwood. That shit will buckle easy if it gets wet. That hole may of solved the problem of the floor buckling and in case the washer ever overflows again you’re good to go. Just a theory.
  17. But it would have to run on the floor in order to get to the pan. The washer doesn’t sit on the grate. And it’s not sealed from the floor to the framing. Makes me believe that whatever it’s intended for would have to be directly above the wood grate.
  18. Yes but the little time it’s wet won’t hurt hardwood if it’s sealed good. Water standing is what ruins it. I’m so serious to man. I had to rip one out once 3500 sq ft. Plumbing line busted while they were out of town. It picked the damn furniture up off the floor. No lie it was horrible. Some places was up to 18” high. Myself personally I had never known hardwood would do that. I thought oak had very little expanding and contracting but not so when it gets flooded.
  19. Any chance it’s near a beach?A slight variation on u/WillyPete ‘s thinking: it reminds me of the drain for an outdoor shower at a beach house I visited when I was a kid. Sand would clog the indoor plumbing, so we had to rinse off outside.
  20. Depending on the location, I’m thinking that an old-style electric washing machine with the wringer mechanism, or as mentioned by others, wash tubs with manual wringers, may have been located here. Both of my grandmothers had the old electric style that they positioned next to the floor drains in their cellars. A lot of water splashed on the floor when using those machines. At one time, the entire wood floor may not have been there, and the washing machine may have been placed on the concrete floor.
  21. It could be for a drip rack, my grand parents had a canning room in their farmhouse that had a floor drain for washing mass amounts of vegetables. That seems a bit odd to stick in the middle of pumpkin pine floors
  22. I’m guessing it’s a dog washing station. Is there a sink to hook up a hose?My bet is it was somebodies idea for creating a dog wash for large dogs.
  23. Basement was previously unfinished with a floor drain, very common. Someone added a raised floor over the original cement but left access to the old drain. This is good.

What do you think it is for? Let us know in the comment!



In the realm of home renovations, surprises often lurk behind every corner, waiting to be uncovered by the keen eye of the renovator. Such was the case for one intrepid individual working on a house project, who stumbled upon a peculiar feature in the laundry room that left them scratching their head in bewilderment – a weird drain in the floor with a hinged grate/lid and a sheet metal pan. As they delved deeper into the mystery, they discovered that the drain was not connected to the septic system, nor did it have a trap; instead, it drained out of the foundation under the back deck. With the previous homeowner, an elderly man, now departed, the renovator found themselves facing a conundrum – what could this strange drain possibly be for?

As the renovator pondered the purpose of the mysterious drain, they were confronted with a multitude of questions and possibilities. Why was there a hinged grate/lid covering the drain? What was the significance of the sheet metal pan beneath it? And most perplexing of all, why was the drain not connected to the septic system or equipped with a trap?

One plausible explanation for the presence of the weird drain in the floor is that it served as a means of managing water runoff or drainage from the laundry room. Given that the wood on top of the drain appeared to be pressure-treated, it suggested that the area was intended to withstand exposure to moisture. This led to the hypothesis that the drain may have been designed to collect water from the laundry appliances, such as a washing machine or utility sink, and channel it away from the interior of the house to prevent flooding or water damage.

The hinged grate/lid covering the drain could have been intended to provide access for cleaning or maintenance purposes, allowing the homeowner to periodically remove debris or buildup that might accumulate over time. Similarly, the sheet metal pan beneath the grate/lid may have been installed to catch any water that seeped through the grate, ensuring that it was directed into the drain and not allowed to pool on the floor.

Another possibility is that the weird drain in the floor served as a point of egress for excess water or moisture that accumulated beneath the back deck. In regions prone to heavy rainfall or high groundwater levels, it is not uncommon for water to collect around the foundation of a house, posing a risk of flooding or water intrusion. By routing the drain to discharge outside the foundation, it may have served as a proactive measure to prevent water from seeping into the basement or crawlspace and causing damage to the structure.

Despite these speculative explanations, the true purpose of the weird drain in the floor remains elusive, its origins and function shrouded in mystery. With the elderly homeowner who installed it no longer available to provide insight, the renovator is left to ponder the enigma of the drain and devise their own theories as to its intended use.

As they continue their work on the house renovation, the renovator remains vigilant for any further clues or revelations that may shed light on the mysterious drain. Whether it be through archival research, consultation with experts, or serendipitous discoveries, they are determined to unravel the secrets of this unconventional feature and uncover the truth hidden beneath the surface of the floor.

In the end, the weird drain in the floor serves as a reminder of the unexpected surprises that can arise during a home renovation project. While its purpose may remain a mystery for now, it stands as a testament to the ingenuity and resourcefulness of homeowners past and present, who have sought innovative solutions to the challenges of maintaining and preserving their homes for future generations.

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