Okay, so have a client who went through all kinds of local pcos before one told her to call us. She had some wildlife entry points back then (last year)
and we resolved those with exclusion, no more noises under the house or foundation, simple structure, flat roof, stucco sides so entry points generally on this
type of home in our area for things larger than mice or rats are roof vents, crawlspace or foundation vents and of course the access panel to the crawlspace outside.

With everything outdoors I never saw something that would be making the noises she was hearing, we actually told her we didn't believe the exclusion outside would
resolve anything other than keeping the skunks and rock squirrels at bay, wasn't related to these strange noises. She still wanted the perimeter secured so we did that.

Periodically she would check in over the last few months to mention still hearing noises. I went out, crawled through both parts of the crawlspace (one dirt, one nice concrete).

Neither had sign of literally anything new or active and lots of mouse and rat traps and bait stations from the old companyies were still there set and missing bait.

She is a nice lady, reasonable, never believed she wasn't hearing something but literally couldn't figure this one out.

So here we are months later (many months) and for her more than a year since she started with these random noises in the night. Finally I went over at night to try to get a listen
knowing full well it wasn't going to happen while i was there which it didn't.

I checked the crawlspace from inside a closet just to look around with the spotlight for eye shine, droppings, digging, etc... Dead mouse in an old t'rex trap. Outdoors all materials for exclusion solidly in place, nothing that shows any form of entry.

She has a small voice recorder she bought when the pest guys were failing to figure it out way back when. Pulls that out and plays it for me and sure enough sounds like "popping" no scratching, no gnawing, "popping."

So here is the rub. I realize sometimes it is a structural component in the home that is making the noise but on this house not sure what it would be. She will get up out of bed and pound on the floor and it will move to the other end of the house (below the floor). I explained that it isn't running on any joist as there isn't a way to do so under the house versus above the ceiling so what on earth is in this house that is "popping?"

Was hoping someone has had a "popping" issue before in a house or structure and has some wild idea. We have mice, rats, squirrels, lizards of all sizes, plenty of insects and on up to the normal skunks etc...

I put cameras out today on the roof, in the yard facing the access panel (though excluded) and another elsewhere, hoping to document something, but literally don't believe this is a biological issue.

Random thoughts appreciated....

Plumbing or heater vent pipe maybe?

You don't mention type of heat, Hot water, Forced hot air, Electric. Noise at night only or daytime to. Had a home with crawlspace, with forced hot air heat, client was hearing sounds at night, but not durning the day, Because nobody was home. Turned out they had heat ducks that were made of that lite aluminum, a couple spots close to the blower were tore or loose, when the blower came on, the aluminum would make a noise & would sound like it was moving around with the speed of the fan blowing. Could be a fitting loose on heat / air cond. unit also.

Good idea about the heater ducts the house itself was old so for this area walls were pumice though the house has been added to. She has forced air heat. She is very convinced it stops or moves when she makes noises back to make it stop. This is the hard part to split off as it seems like an animal running elsewhere versus a utilities (non biological) to her.

Maybe she should have the ducts scoped by an HVAC with the cam?

I've seen plenty of houses including one I renovated where the ducts came loose and fell apart good thought!

air pocket that is released by the pounding? like a vent pipe that has a flap that is getting stuck once in awhile and when it is released it is sending the noise to the end of the pipe as it exits?

What time of day does she hear it? Is it consistent at those times?
Vinyl siding will pop as it warms in the morning sun or cools in the evening, if it was put on too tight.

I've had an electrical primary stretched over a 1" branch of a tree, that when the wind blew, it would send all kinds of sounds into the wall of the house where it was attached. Took me two visits to figure that one out. It worked just like stretching two soup cans on a string (home made kiddie phone back in the day).

I've also had people that are just crazy, senile, or on halucinating meds. Not to mention chirping smoke detectors.

Yeah chirping smoke detectors...lol...had a client down in missouri call me to get squirrels out of attic cause her "handyman" told her that chirping noise was squirrels

Josh, That is a possibility I hadn't thought of in terms of releasing whatever it is by pounding. Apparently vocalizing toward it without pounding as well has made the sound move so I'm not sure how that plays in, but the theory is a good one!

Brian, Time of day is somewhat tricky in terms of her main use of the home is only after hours, she rarely uses the house during the day even on weekends (very driven professional).

The voice recorder definitely has sounds I can hear on it, though I agree as I've had people with phantom mice or rats that were ultimately referred to us after pest guys gave money back and we went looked, found nothing as well and walked away quickly (or slowly without turning our backs - lol). Had a call last year with some of our city work where a guy insisted there was a raccoon inside his reclining sectional chair. Did a whole property assessment where he noted he had activity without finding anything and when myself and my counterpart from the municipality went inside the house he (the owner) mentions he is sure it is inside the chair (tightly upholstered style). I look at the chair under, behind, etc... roll it over, nothing, no chewing no damage, okay so we are leaving... Nope he pulls out a box cutter and starts to say we should dismantle it to which I state, if you want to you can do that, I'm confident there isn't an animal in there, have a good day let us know if you find anything, but we are sure nothing is here. As I'm talking he starts cutting open the chair like something from a movie...

I'm motioning to the counterpart that we need to extract ourselves before we become part of an ID channel segment... Left quickly and honestly one of few times in my life around folks within the continental U.S. that I've felt concerned for my life around!

Okay, sidebar, back to this deal, I'm always thinking water hammer (have had that in my own home), material flapping or pulling (this house is built in the 40's or 50's, single story, small footprint maybe 1200 sq ft max, flat roof, adobe (stucco) exterior, one access point to crawlspace, all trees have been trimmed back from the house to keep the possibility of them flapping against the house or causing issues. All of her vents were screened over before I got there, simple hardware cloth but it is all still in place from the previous companies.

Have had the smoke detectors as well, always a funny look on folks faces when you show them that!

I've got the cameras out till the weekend this week and will report back on any findings or lack thereof. The fact the noise travels below the floor to the other end of the house (40' max) really makes me think it is mechanical or structural, but these ideas from all of you help me give her a laundry list if I don't come up with something so she can pursue further. I mentioned that if the noise is always in one spot within the wall that opening that up may be the only answer.

Other than the dead mouse she has zero sign of any wildlife in her structure including the crawlspace and roof top. Trying to explain to someone losing sleep over noises like this over so long of a time that biological beings leave biological signs is a tough sell at this point, just seems logical to folks that it must be an animal (and who knows maybe it is)...

Thanks for continued thoughts!

Justin

Can't imagine why the sound moves when you bang on the floor, but my house has popping noises that are caused by expansion and contraction. Temperature changes and humidity changes seem to cause them. Every year in the spring and end of summer I hear more than normal popping noises as the house expands as it heats up and contracts as it cools down. After a long period of dry weather if we have several days of wet weather there are popping noises. But they seem to be wall and eave height, not under the floor.

Maybe keep track of outside weather and temp near the house and indoor temp and humidity over a period of time and see if there is any correlation between when the sounds are heard and the data.

Almost exact same thing happened to me. Don't remember what my customer thought was in the chair, but after looking it over like you, he grabs a butcher knife and asks ME to cut it open. I said no of course, so he starts hacking away at the chair. Destroyed the dang thing and asked me to help take it outside. That one was weird for sure.

I wonder if it was the same brand of chair. lol.

Wind getting behind a loose piece of siding can make a slapping "POP" sound. I have that problem right now, AND sometimes the ice maker will catch a cube in the paddles and go "CRACK".

It is bats...in the belfry. If you don't hear it, it ain't there. Bless her heart.

52Carl,

I've had the folks who had slipped from reality before, this lady isn't that scenario, as I mentioned above she has a sleuth of audio recordings and played them for me and the description matches
what she said the sound was like.

She's a top notch pro in her field in this area not that it makes you a sane person, but nothing about this reads off, just that I haven't found what is causing it and may never. Going to have her have her duct work scoped and checking the cameras tomorrow while going out to try to catch a coyote with a foothold that some urban knothead decided to put out in a residential area...

Will update once I look at the cams though I believe this is something structural or mechanical related to the house itself, not biological.

I have had a few jobs that the heat ducts made popping noises at the section joints and would move just like something moving along the vent. I figured out the first time by shear frustration. I asked the customer to turn the heat on. and sure enough with in a few mins the noise started closest to the heater and moved right down the line. each joint only made noise once then the next one the same. Turned the heat off and it came back from the farthest point back to the heater.

X2 what Jonesie said.

a drunk hiding in the basement popping cans of Bud...

Heading toward a firm mechanical or structural diagnoses.

Three cameras (flat roof, side yard facing crawlspace access,
another facing major wall along exterior of house), only witnessed in 5
days and nights, one skunk poking around edge for a few moments, couple of robins during
day and nothing else....

Appreciate everyone mentioning the various duct and pipe ideas. Helping her head that direction to try to
determine the source of possible but finally have her believing we aren't chasing any animals at this point.

Will update if we find the source... This style of house in our state usually has the least vulnerable rating when compared to other types. All vents and the whole exterior are solid or excluded solidly for a long time now. This definitely smells of structure but we'll see...