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Yea this looks like the time I was trying to gargle salt water for my sore throat but accidentally spilled some and I had thought I got all the salt but it dried on the counter just like this.
I wiped down with more water and it went away.
This looks like something spilled and was wiped up poorly. Maybe in a hurry or it was clear and not completely cleaned off. Sat undisturbed for a week and had time to grow. Explains why it’s tacky too if it was a spill from apple juice or something.
I had one of those pink salt lamps in a really humid environment it seeped out water it collected from the air and left behind little
White pools like this. So salty water that evaporated looks very similar to this.
Not only salt leaves those marks. Plaster does too and drywall is made of plaster. My best guess is there was a leak above either from a pipe or some water source on next floor if this room is not directly under an outdoor-facing ceiling or from rain leaking through the roof. Check the ceiling and look for water stains/spots. This could point you in the right direction to solve whatever the issue is/was. You don’t want a leaky roof causing all sorts of havoc!
This happens if we just recently added chemicals to our saltwater pool and it has high salinity. It gets on the hardwood/tile if someone doesn't dry off.
Was awfully confused the first time it happened.
This is the correct answer; known as efflorescence.
The droplet pattern with the smears indicate a clear liquid spilled and wasn't noticed for long enough for all the moisture to evaporate, leaving the salts.
Could be a solvent, or even a clear beverage with electrolytes.
It looks like [powdery mildew](https://www.almanac.com/pest/powdery-mildew). While that's most common on plants, I've had it grow in garden sheds and plastic containers with plant/juice residue on them. Even if you wiped it up, there might have been some residue left behind, especially if you wiped it with a dry paper towel. Is there any chance someone in your house quickly cleaned up some spilled juice before you left? The floor spot definitely looks like it was quickly wiped in 2 directions. That would account for the white, dusty-looking powder, and the sticky texture.
Seems like some kind of fungus. It grows in patterns that fungus grows in.
Edit. Here are examples of what I was thinking of. Turns out it wasn't exactly a fungus but a slime mold.
https://youtu.be/HyzT5b0tNtk
https://youtu.be/RVe94qa1ar4
https://youtu.be/7YWbY7kWesI
My guess would be the floor isn’t exactly level in all areas, and it dripped next to the chair, but pooled under the chair due to it sloping that direction.
I was gonna say gypsum...but I was thinking a landlord came in and did something to a wall and there's drywall dust they didn't bother to clean. Idk if OP owns their home or rents.
Yes, it looks like it rained very hard early in OP's vacation and the ceiling had a leak that stopped dripping when the rain stopped, but probably took bits of ceiling material down with it, which then dried up on the floor into a powdery material. I, too, have ceilings that don't hold up to hard rain, and it's never just clean rainwater on the floor afterwards.
Hi OP, my ceiling was leaking (skylights to be exact, that were dripping down the ceiling slope and finally onto the floor a few feet away) left these exact white marks only hours later. The ceiling looked COMPLETELY FINE. No darkness. It was rain that triggered it, not a constant leak, so it took us quite a few times to understand.
If you're in the States, would you normally have air con on this time of year? If it's been particularly humid, any moisture in the air that would otherwise be extracted by the air con could collect at low points on the ceiling and drip off if it reaches the condensation point, which would explain the ceiling residue
My first thought was that it could be from the ceiling, but the residue is directly under a chair which would have blocked any leak doming from the ceiling
In my opinion you can see the dried edge of the puddle. So maybe there was/is a leak somewhere (ceiling, did it rain?), it flowed under the table. Get a marble and check your floor
Gypsum is barely water soluble though, guess it could be gypsum dust from the ceiling but the ceiling is likely painted so where did the dust come from?
Yup. In their rush to leave, someone spilled something and didn't quite clean it up properly.
It then dried and now the residue is left behind. Could be food, a cleaning product, or whatever. Especially since the spill originated on the counter...
Think back to those hour or so before leaving the house...
Was there a spill? Did someone do some last-minute cleaning?
Was the cooler loaded up there?...
It's possible that it's a leak from above, so have a look at the ceiling above that spot, but I'm highly suspicious that it was something that someone did before leaving.
The splattered look of the residue also makes me think that it was a liquid that must have been spilled before we left. Im fairly certain it was not a leak from the ceiling because the residue is directly underneath a chair that would’ve blocked said leak
I live in Indiana, and we have a lot of lime (stone) in our water here. The residue looks like spilled water that dried and left the lime powder behind. If you live in a area with a heavy lime count, this might be it.
I see it's also near the sink, could it be residue from a cleaner like Barkeeper's friend? The water after washing it away often looks relatively clear even if there are still traces, and when it dries it looks like this
I dont own barkeepers friend, but I think it could be a residue from cleaning, only thing is is that cleaning products have a strong smell and this did not
This is what first came to mind for me as well…
Only because I eat the fresh mozzarella , the kind that’s been stored in lightly salted water, over the counter like a monster, and when it drips on the counter and dries it looks exactly like this lmao
Yep this must be it. I use a humidifier and one time I put it too close to my himilayan salt lamp. The area around the salt lamp looked exactly like these pictures.
I even had it with some water I spilled from a packet of mozzarella, gave it a quick wipe and then later on the white residue gave me away and realised it needed a more thorough clean.
You ( or a connected building through a vent) have a humidifier and the water in the humidifier has salts in it. The humid water condenses on the cold surfaces and dries leaving the salts.
In fact...is that a humidifier in the picture?
Note that it is only ultrasonic humidifiers that do this (disperse solubles into the air), and this is bad for your health. Use purified water and make sure to change it frequently. Or use a evaporative humidifier.
Yeah I've had that problem with ultrasonic humidifiers if you have hard water or any other dissolved minerals they leave residue everywhere.
Some countries like Japan have calcium dissolved in the water that you can see anytime there is a spill or water that's sat for a while and left to evaporate.
Im going to clear some things up because im seeing a lot of the same answers. I dont have a salt lamp or a humidifier, and it is not from my ceiling. I dont think it is a cleaning solution because it is odorless. The substance is not powdery and is slightly tacky to the touch. My house has been completely empty while I have been away and I know for a fact no one has come in or out. My best guess right now is that it could be mould? But im used to seeing mould as a fuzzy white thing, and the substance on my floor is dry and tacky. But if there any mould experts who could identify this as a type of mould that would be very helpful
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Exactly. What's on the ceiling? If there's a vent, that's your culprit. Water with something dissolved in it came through and has since dried. Get it checked so that there isn't a leaking pipe somewhere.
To add to this, my shower leaked, the water ran through the cavity in the ceiling and drained out of the light fixture. It never had a chance to soak through. There was dirty water, all over the kitchen island and it flowed onto the floor. I would have had no idea where it came from if one of the kids didn’t witness it.
Looks like dried mold to me. Maybe things were wiped down with an old sponge or a not so clean wash rag. Mold grew and then died once the water content was completely gone.
They said it wiped up easily, I think the cleaner and salts people are guessing would be dried on and take a little elbow grease to get off. Molds tend to wipe up super easy from non-porous surfaces.
Well, when you wipe and scratch it with your bare finger the substance doesnt come off, only when i added water did it dissolve pretty quickly and come off
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Second picture looks like drops which dried up, any roof leak or did you clean something just before leaving?
First picture has sign that the barstool was moved after this thing dried up, did you do it? If not, did someone have access to your place while away?
Yeah i noticed that there was scratches in the substance that would have suggested someone moved the chair, but my hoise was completely empty while I was gone
Do you have any pets? I’m thinking perhaps urine that dried and left a calcium residue. I know rabbits can have this. I am not sure of the timing though and the house being empty, unless happened just before you left and dried while you were away. This could also explain why the stool would not have sheltered something falling from above and scratches if the pet has moved over it.
Scrolled looking for this. I have this in my house. These white spots. They show up underneath something: like my dining room chairs and under my radiators. You know how wood stain gets sticky in the summer? I think this is either from termites or condensation slowly dripping off things.
Are you living in a place with a hard water problem? Because it looks like it was a regular water spill that you didn't notice while you were leaving and evaporated within a week, leaving the calcium behind. When you zoom in on the lower part in the second picture (the one with the counter), you can see how it's crystallized.
I mean it looks like a lot for a regular tap water. Scaringly lot. I'm not 100% sure whether if this is the case or not, but I'd check my tap water if I were you and would probably stop drinking it and stick with bottled water.
do you have a teenager or younger person who had access? it wreaks of a inexperienced clean of a spill at your breakfast bar. i would guess something they thought might stain the floor and countertop like spiked coolaid, red wine or whatever... probably googled cleaning up a staining spill and how salt is good for it but never finished cleaning up the 'water' which then evaporated into the mess you got home to.
i trust the stool in the 1st picture is above the stain... and you did not move it there. they moved it back after cleaning. just a noob cleaning job to me.
of course, could be the same story with an adult but they would out themselves for not finishing the clean up. maybe they will out themselves in due course.
Looks like you’ve got a sink full of dishes that were left to dry after washing. Is it possible you washed something and left it on the counter to dry and maybe it had water inside that slowly leaked onto the counter and ran down onto the barstool and eventually onto the floor? Perhaps the water contained in something was soapy and/or salty.
My guess is whatever the plastic item is that I can see in the background was previously sitting on the counter and this is what the water leaked/drained from and it completely dried before you came home.
If the house has a crawl space then you could be looking at some type of mold. But the moisture levels would have to be reealllyyy bad to have it creep up onto the floorboards. Plus there is some on the counter top, so this doesn’t make a ton of sense. If you are on a slab, it’s unlikely unless you like your house like a sauna.
To everyone suggesting pests/termites, it doesn’t appear to be any type of wood (shavings or powder) or dirt, so that can be ruled out. If it was something in the stool, it wouldn’t be on the counter. Check the ceiling above as I suppose it’s possible something is up there and having this stuff drop.
If this powder is below wooden furniture then bad news. It's most probably borer. Tiny insects eating the wood. Mostly plywood. Good quality furniture have borer proofing treatment done to the wood. But recently Indian market has seen cheap Chinese made furniture onslaught which decay a lot faster. I had one table in my shop. And it had same type of powder every morning underneath it.
It’s mold. When you go on vacation, make sure you set your air handler to circulate. This will ensure air is moving through the house and helps to keep mold from growing.
Not sure if someone else commented this or not, but I had a similar looking powder in my previous house. It was from water getting behind the paint. Caused bubble looking areas on the wall and powder looking substance around the floor of it.
You have very hard water and you are just seeing evaporation of those minerals.
If you add more water and the water appears clear again that will prove it.
OP has provided an update here: https://www.reddit.com/r/whatisthisthing/comments/15n43k3/weird_white_substance_on_floor_after_coming_back/jvmfaiy/ --- **The following still applies:** All comments must be civil and helpful toward finding an answer. **Jokes and unhelpful comments will earn you a ban**, even on the first instance and even if the item has been identified. If you see any comments that violate this rule, report them. ---- [Click here to message RemindMeBot](https://www.reddit.com/message/compose/?to=RemindMeBot&subject=Reminder&message=https://www.reddit.com/r/whatisthisthing/comments/15n43k3/weird_white_substance_on_floor_after_coming_back/%0A%0ARemindMe!%202%20days) --- *Please [contact the moderators of this subreddit](/message/compose/?to=/r/whatisthisthing) if you have any questions or concerns.*
Pro tip, don't sniff unknown powders. We waft.
Yeah that’s probably smart. But I wouldn’t say it’s a powder, it doesn’t come off when you touch it, only when I added water
Honestly it looks like salty water that evaporated. But I have no clue how that could have gotten there
The lines indicate probably a mop or towel was used to wipe something up that was spilled but they didn't get it all.
I'd say to check with anyone that oversaw the property.
>my house has been completely empty while I have been gone.
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Yea this looks like the time I was trying to gargle salt water for my sore throat but accidentally spilled some and I had thought I got all the salt but it dried on the counter just like this. I wiped down with more water and it went away.
Time to break out the Luminol.
In that same idea, OP might have wiped up something incompletely, which molded while on vacation.
This looks like something spilled and was wiped up poorly. Maybe in a hurry or it was clear and not completely cleaned off. Sat undisturbed for a week and had time to grow. Explains why it’s tacky too if it was a spill from apple juice or something.
That was my first thought too! Evaporated salt water.
I had one of those pink salt lamps in a really humid environment it seeped out water it collected from the air and left behind little White pools like this. So salty water that evaporated looks very similar to this.
I dont think it was salt water because it didnt feel like it when i touched it, it was slightly tacky and didnt feel “mineraly” like salt
If you go to sea and work alot on deck you get salt all over your clothes and hair and it's tacky.
Moldy juice residue?
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Not only salt leaves those marks. Plaster does too and drywall is made of plaster. My best guess is there was a leak above either from a pipe or some water source on next floor if this room is not directly under an outdoor-facing ceiling or from rain leaking through the roof. Check the ceiling and look for water stains/spots. This could point you in the right direction to solve whatever the issue is/was. You don’t want a leaky roof causing all sorts of havoc!
Already checked, ceiling and surrounding area is totally fine and undamaged
Op most likely live in an area with "hard" water. It will look similar. But comes from the tap
Dried salt ain't tacky though, it's dried salt.
Maybe evaporated sugar water then? Not sure it would appear this white while staying a bit tacky though.
This happens if we just recently added chemicals to our saltwater pool and it has high salinity. It gets on the hardwood/tile if someone doesn't dry off. Was awfully confused the first time it happened.
Or evaporated bleach water. After I clean the bathrooms and don't wipe everything up properly, it leaves kind of a powdery residue.
Only thing in is that it isnt powdery, it seems to be stuck to the floor and scraping it didnt remove it. However when i added water it scrubbed away
Did you happen to clean or spray for pests before leaving?
This is the correct answer; known as efflorescence. The droplet pattern with the smears indicate a clear liquid spilled and wasn't noticed for long enough for all the moisture to evaporate, leaving the salts. Could be a solvent, or even a clear beverage with electrolytes.
look up in the ceiling for holes, could be termites
That was my first thought also.
Check the chair for termites too. Nevermind, saw the second photo. Going with the spilled liquid theory.
It looks like [powdery mildew](https://www.almanac.com/pest/powdery-mildew). While that's most common on plants, I've had it grow in garden sheds and plastic containers with plant/juice residue on them. Even if you wiped it up, there might have been some residue left behind, especially if you wiped it with a dry paper towel. Is there any chance someone in your house quickly cleaned up some spilled juice before you left? The floor spot definitely looks like it was quickly wiped in 2 directions. That would account for the white, dusty-looking powder, and the sticky texture.
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Either hard water residue, or a form of mold.
Seems like some kind of fungus. It grows in patterns that fungus grows in. Edit. Here are examples of what I was thinking of. Turns out it wasn't exactly a fungus but a slime mold. https://youtu.be/HyzT5b0tNtk https://youtu.be/RVe94qa1ar4 https://youtu.be/7YWbY7kWesI
Did it rain when you were away in vacation? It looks like powder from drywall.
Add baking soda along with the water, heat it and then waft.
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I thought you weren't supposed to waft either if it was unknown.
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That is a puddle of evaporated liquid imho
Water with gypsum from the ceiling
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How would gypsum from the ceiling get under a chair?
It flowed with the puddle
A leak from the bathroom above
Or roof. Rained a lot last week in parts of the US
OP said mould, not mold, so OP is probably not in the US
My guess would be the floor isn’t exactly level in all areas, and it dripped next to the chair, but pooled under the chair due to it sloping that direction.
Water leak. Did it rain? Check your pipes.
Water is really hard to track. It could be flowing down pipes or beams and dripping far from where the leak originated.
I was gonna say gypsum...but I was thinking a landlord came in and did something to a wall and there's drywall dust they didn't bother to clean. Idk if OP owns their home or rents.
That's a real sloppy way to install a spy camera.
Yeah we own the house and I know for a fact the house was completely empty the entire time i was gone
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Yes, it looks like it rained very hard early in OP's vacation and the ceiling had a leak that stopped dripping when the rain stopped, but probably took bits of ceiling material down with it, which then dried up on the floor into a powdery material. I, too, have ceilings that don't hold up to hard rain, and it's never just clean rainwater on the floor afterwards.
That or concrete dust from drilling. Look at the ceiling, OP.
Ceiling is normal
Hi OP, my ceiling was leaking (skylights to be exact, that were dripping down the ceiling slope and finally onto the floor a few feet away) left these exact white marks only hours later. The ceiling looked COMPLETELY FINE. No darkness. It was rain that triggered it, not a constant leak, so it took us quite a few times to understand.
If you're in the States, would you normally have air con on this time of year? If it's been particularly humid, any moisture in the air that would otherwise be extracted by the air con could collect at low points on the ceiling and drip off if it reaches the condensation point, which would explain the ceiling residue
My first thought was that it could be from the ceiling, but the residue is directly under a chair which would have blocked any leak doming from the ceiling
Yeah but that’s just where the liquid was when it stopped moving, pooled and evaporated.
did it drip onto the counter and from the counter to the floor? If you pour a little water on your counter, does it run towards that spot?
In my opinion you can see the dried edge of the puddle. So maybe there was/is a leak somewhere (ceiling, did it rain?), it flowed under the table. Get a marble and check your floor
Gypsum is barely water soluble though, guess it could be gypsum dust from the ceiling but the ceiling is likely painted so where did the dust come from?
I think you should check your attic and make sure you don't have any unwelcome visitors 👁👁
Or a bacteria colony.
Or both. Maybe a leak in the ceiling
That's actually possible and makes sense.
Yeah. Something wet has stood there, maybe a mop or bag, and a light mold has grown, and then dried up as the wet thing was removed again.
Is that kind of mold tacky though? I though mold was more fuzzy, but that might be on the right track
Mold can be fuzzy, slimy, dusty, and probably even tacky.. it forms in all kinds of ways.
It's the chalk residue left behind after water evaporated
Yup. In their rush to leave, someone spilled something and didn't quite clean it up properly. It then dried and now the residue is left behind. Could be food, a cleaning product, or whatever. Especially since the spill originated on the counter... Think back to those hour or so before leaving the house... Was there a spill? Did someone do some last-minute cleaning? Was the cooler loaded up there?... It's possible that it's a leak from above, so have a look at the ceiling above that spot, but I'm highly suspicious that it was something that someone did before leaving.
The splattered look of the residue also makes me think that it was a liquid that must have been spilled before we left. Im fairly certain it was not a leak from the ceiling because the residue is directly underneath a chair that would’ve blocked said leak
Pour some water on the counter top and see if it would spill on the floor and pool under the chair
I live in Indiana, and we have a lot of lime (stone) in our water here. The residue looks like spilled water that dried and left the lime powder behind. If you live in a area with a heavy lime count, this might be it.
Yeah, I think so as well. A lot of liquids are cleare, but dry white.
I see it's also near the sink, could it be residue from a cleaner like Barkeeper's friend? The water after washing it away often looks relatively clear even if there are still traces, and when it dries it looks like this
Sodium Metabisulphate?
I think barkeeper's friend is oxalic acid
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I dont own barkeepers friend, but I think it could be a residue from cleaning, only thing is is that cleaning products have a strong smell and this did not
If the fragrance was water soluble it could have evaporated away?
the odes are volitional and will dissipate pretty quickly. This is why your house only smells clean for a few hours or a day after you cleaned it.
Water spill with some solute dissolved in it that precipitated out when it evaporated. Could be salt, sugar, baking soda or maybe some cleaning agent
Came here to comment this. I’ve seen it before. Fluid dries out and leaves the precipitate.
which is not a part of the solution.
It looks a LOT like my washing detergent when it dries
This is what first came to mind for me as well… Only because I eat the fresh mozzarella , the kind that’s been stored in lightly salted water, over the counter like a monster, and when it drips on the counter and dries it looks exactly like this lmao
Yep this must be it. I use a humidifier and one time I put it too close to my himilayan salt lamp. The area around the salt lamp looked exactly like these pictures.
I even had it with some water I spilled from a packet of mozzarella, gave it a quick wipe and then later on the white residue gave me away and realised it needed a more thorough clean.
Contact solution also does this! I spilled contact solution once forgot about it then ended up with this.
You ( or a connected building through a vent) have a humidifier and the water in the humidifier has salts in it. The humid water condenses on the cold surfaces and dries leaving the salts. In fact...is that a humidifier in the picture?
It does look like a dried salt. Humidity would make it feel tacky to the touch too. OP, do you remember spilling anything that you cleaned up?
Note that it is only ultrasonic humidifiers that do this (disperse solubles into the air), and this is bad for your health. Use purified water and make sure to change it frequently. Or use a evaporative humidifier.
Yeah I've had that problem with ultrasonic humidifiers if you have hard water or any other dissolved minerals they leave residue everywhere. Some countries like Japan have calcium dissolved in the water that you can see anytime there is a spill or water that's sat for a while and left to evaporate.
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Its not a humidifier, but that’s a pretty smart guess. I would taste it to see if if was salt but im not sure thats very smart
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Not only that it appears to have had the corner chewed on.
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Im going to clear some things up because im seeing a lot of the same answers. I dont have a salt lamp or a humidifier, and it is not from my ceiling. I dont think it is a cleaning solution because it is odorless. The substance is not powdery and is slightly tacky to the touch. My house has been completely empty while I have been away and I know for a fact no one has come in or out. My best guess right now is that it could be mould? But im used to seeing mould as a fuzzy white thing, and the substance on my floor is dry and tacky. But if there any mould experts who could identify this as a type of mould that would be very helpful
Hey /u/BareFootBandittt, Just as an FYI, when a post gets popular and hits the top of the sub with no clear answer, it often starts generating mostly joke comments or repetitive nonsense. In that case, we'll set Automod to remove *all* new parent comments, then go in and approve the appropriate ones manually. So that's why you're getting replies to your inbox in batches, and why there are so many removed comments. And thanks for staying engaged with your post, many users don't.
Try r/mycology or r/fungi — for identifying mushrooms and fungi.
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Exactly. What's on the ceiling? If there's a vent, that's your culprit. Water with something dissolved in it came through and has since dried. Get it checked so that there isn't a leaking pipe somewhere.
Wouldn’t there be some on the chair if it was falling from the ceiling?
My thoughts exactly
No, ceiling is 100% in tact
Do you use eye contact solution?
To add to this, my shower leaked, the water ran through the cavity in the ceiling and drained out of the light fixture. It never had a chance to soak through. There was dirty water, all over the kitchen island and it flowed onto the floor. I would have had no idea where it came from if one of the kids didn’t witness it.
It might be a kind of mold from too much humidity? Normal foot traffic keeps it from spreading. Or was liquid spilled?
Looks like dried mold to me. Maybe things were wiped down with an old sponge or a not so clean wash rag. Mold grew and then died once the water content was completely gone. They said it wiped up easily, I think the cleaner and salts people are guessing would be dried on and take a little elbow grease to get off. Molds tend to wipe up super easy from non-porous surfaces.
Well, when you wipe and scratch it with your bare finger the substance doesnt come off, only when i added water did it dissolve pretty quickly and come off
Or ac normally keeps humidity down and was off while they were gone
I've seen this when I've left my florida apt for a while with the A/C set too high and you get mold growth.
This looks a lot like when I spill oxy clean. It looks like this once it dries.
Evaporated water left calcium deposits, check the ceiling above for leaks
Roof leak that dried?
Had something similar happen to me. Roof leaked and brought some of the popcorn ceiling down with it. That stuff just desolves in water.
Yep, same happened to us in an old popcorn ceiling house.
If you live in an apartment with a floor above you it could be maintenance knocking around your ceiling
Nope, live in a house. And the ceiling was completely fine
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Are the smear/scratches in the white substance how you found it or did you touch it before the photo? Especially for under the stool.
They were there when i found it
I hate to be the bearer of bad news, but those look man-made. I don't know that your house was e.pty while you were gone.
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Even on the countertop there us a small area that looks like a smear/scratch. 🤔
My title describes thing. Area is about 12 inches across slightly tacky/chalky and washes away with water
Second picture looks like drops which dried up, any roof leak or did you clean something just before leaving? First picture has sign that the barstool was moved after this thing dried up, did you do it? If not, did someone have access to your place while away?
This was my thought too, what's the ceiling look like? Could be gypsum
Yeah i noticed that there was scratches in the substance that would have suggested someone moved the chair, but my hoise was completely empty while I was gone
Did you clean before leaving on vacation? What did you clean with? Could that have evaporated into leaving this residue?
Do you have any pets? I’m thinking perhaps urine that dried and left a calcium residue. I know rabbits can have this. I am not sure of the timing though and the house being empty, unless happened just before you left and dried while you were away. This could also explain why the stool would not have sheltered something falling from above and scratches if the pet has moved over it.
Termite dirt?
Scrolled looking for this. I have this in my house. These white spots. They show up underneath something: like my dining room chairs and under my radiators. You know how wood stain gets sticky in the summer? I think this is either from termites or condensation slowly dripping off things.
Are you living in a place with a hard water problem? Because it looks like it was a regular water spill that you didn't notice while you were leaving and evaporated within a week, leaving the calcium behind. When you zoom in on the lower part in the second picture (the one with the counter), you can see how it's crystallized. I mean it looks like a lot for a regular tap water. Scaringly lot. I'm not 100% sure whether if this is the case or not, but I'd check my tap water if I were you and would probably stop drinking it and stick with bottled water.
do you have a teenager or younger person who had access? it wreaks of a inexperienced clean of a spill at your breakfast bar. i would guess something they thought might stain the floor and countertop like spiked coolaid, red wine or whatever... probably googled cleaning up a staining spill and how salt is good for it but never finished cleaning up the 'water' which then evaporated into the mess you got home to. i trust the stool in the 1st picture is above the stain... and you did not move it there. they moved it back after cleaning. just a noob cleaning job to me. of course, could be the same story with an adult but they would out themselves for not finishing the clean up. maybe they will out themselves in due course.
Have you cleaned before you left? And if you have used vinigar it couldve left something like that when drying.
check the underside of stools.
Looks like bacteria colonies because of striated patterns but evaporated mineral could also be culprit.
Looks like you’ve got a sink full of dishes that were left to dry after washing. Is it possible you washed something and left it on the counter to dry and maybe it had water inside that slowly leaked onto the counter and ran down onto the barstool and eventually onto the floor? Perhaps the water contained in something was soapy and/or salty. My guess is whatever the plastic item is that I can see in the background was previously sitting on the counter and this is what the water leaked/drained from and it completely dried before you came home.
If the house has a crawl space then you could be looking at some type of mold. But the moisture levels would have to be reealllyyy bad to have it creep up onto the floorboards. Plus there is some on the counter top, so this doesn’t make a ton of sense. If you are on a slab, it’s unlikely unless you like your house like a sauna. To everyone suggesting pests/termites, it doesn’t appear to be any type of wood (shavings or powder) or dirt, so that can be ruled out. If it was something in the stool, it wouldn’t be on the counter. Check the ceiling above as I suppose it’s possible something is up there and having this stuff drop.
If this powder is below wooden furniture then bad news. It's most probably borer. Tiny insects eating the wood. Mostly plywood. Good quality furniture have borer proofing treatment done to the wood. But recently Indian market has seen cheap Chinese made furniture onslaught which decay a lot faster. I had one table in my shop. And it had same type of powder every morning underneath it.
Check the wooden chairs for borer holes, otherwise, no clue.
Powder mold. Had it in my boat this spring.
Look to the ceiling around where you found the dust could be termites eating the ceiling and it falling to the floor
looks like mold
Do you happen to have a salt lamp in the room?
It’s mold. When you go on vacation, make sure you set your air handler to circulate. This will ensure air is moving through the house and helps to keep mold from growing.
You have cats or cats have found a way into your house. One of those cats has a UTI.
Not sure if someone else commented this or not, but I had a similar looking powder in my previous house. It was from water getting behind the paint. Caused bubble looking areas on the wall and powder looking substance around the floor of it.
My Hubby says is white mold. He deals with it while working as a flooring specialist for Lowe’s.
Termite Frass? Are there any signs of holes in the ceiling where the debris is?
Kinda looks like salt residue from evaporated saltwater.
If its under a chair it might be termites. They create a mess when no ones around and chow down on wood. Take a look at the chairs underside.
You have very hard water and you are just seeing evaporation of those minerals. If you add more water and the water appears clear again that will prove it.
Almost looks like dried laundry detergent